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Updated: 2016-09-01T18:20:05Z


Urban Forestry Video Series New Release!


Trees provide more than just beauty or a source of wood products. Rather, trees provide an assortment of economic, environmental, psychological and social benefits to humans. Energy savings are one such highly valued benefit or service urban trees provide. Did you know that just 17% shade on a building from trees for example can reduce power bills by $10/ month or that urban trees can lower surrounding temperatures by as much as 20° F?  Alternatively, trees can reduce winter heating costs by 15% through wind control. Correct planning, design, and care for urban trees is essential to maximize their energy conserving benefits. The National Urban and Community Forestry Advisory Council sponsored the recent development of a video series demonstrating how care for urban forests leads to energy conservation, in support of the Trees for Energy Conservation eXtension website.  Watch today and learn from national urban forestry experts across a variety of topics, including:      Communities Benefit from Energy-Saving Trees: Urban Forests Role in Heat Reduction Trees for Comfort in Public Places Finding Refuge in the Urban Forest Blending Architecture with the Urban Forest Community Involvement with Urban Forestry      Tree Establishment in the Urban Environment: Establishing Trees for Energy Conservation Staking and Guying Landscape Trees Mulching Trees in the Urban Environment Watering Trees in the Urban Environment Controlling Weeds around Landscape Trees    Communities Benefit from Energy-Saving Trees University of Florida Extension Forester, Robert Northrup, discusses the many benefits of urban forests on energy conservation and human health. In Blending Architecture with the Urban Forest, Florida Extension Forester Robert Northrup discusses how trees create a sense of place; provide a comfortable environment to seek respite in our day-to-day lives; and how well-designed forests lead to notable energy savings. Northrup further explains how the planning and care of trees in the built environment relies on a community of engaged citizens for its success in Community Involvement with Urban Forestry. He points out that “there are costs to the urban forest, but the benefits outweigh those costs, particularly through good, sound management and use of science to guide produce a multitude of benefits.” Urban forests provide a comfortable environment to seek respite in our daily lives. In Finding Refuge in the Urban Forest, Northrup explains how urban forests provide habitat for wildlife, a refuge from the heat and chaos of the city and a source of well-being for city dwellers.   With careful planning, cities can maximize the benefits of urban forests. The video, Trees for Comfort in Public Places, discusses how the city of Tampa has intentionally planned green space in its business districts to encourage people to get outside, which increases shopper foot traffic and boosts worker productivity. He also showcases a “pocket” park where the soil and hardscape has been specially engineered to boost tree growth and longevity, which maximizes shade and comfort. Urban areas tend to be hotter than outlying natural environments, which can impact air quality and human health. Fortunately, urban forests buffer the heat of the sun and cool the urban environment. The Urban Forest’s Role in Heat Reduction describes the urban heating phenomenon and its consequences for people and the environment.   Tree Establishment in the Urban Environment Auburn University Extension Agent, Arnold Brodbeck, demonstrates several maintenance activities that support optimal tree health and energy conservation. Auburn University Extension Agent, Arnold Brodbeck, introduces important tree care practices of mulching, watering, weed control, and support for newly planted trees in Establishing Trees for Energy Conservation. These practices are critical to young tree survival and vigor that maximize energy conservation benefits. In subsequent videos, Bro[...]

Home Energy: Useful tools on the web


Many websites provide tools and information to help home owners, building managers and designers with energy efficiency.  Below is a listing of tools taken from links from Energy Program at  that relate to  energy conservation, alternative energy sources and energy management. Energy Star Home Advisor:  This tool provides consumers with customized recommendations for improving energy efficiency and comfort at home. FEMP Energy and Cost Savings Calculators: for Energy-Efficient Products:  These calculators allow users to enter their own input values (e.g., utility rates, hours of use, etc.) to estimate the energy cost savings from buying a more efficient product. Calculators are available for, but not limited to: compact fluorescent lamps, commercial unitary air conditioners, air cooled chillers, water-cooled chillers, commercial heat pumps, boilers, refrigerators, freezers, beverage vending machines, computers, monitors, faxes, printers, copiers, faucet/showerheads, toilet/urinals, central air conditioners, gas furnaces, electric/gas water heaters, clothes washers, and dish washers. Energy Data and Tools from  This site provides access to a compilation of datasets from multiple Federal agencies (i.e., DOE, EPA, GSA) concerning multiple aspects of energy. Examples of available datasets include data about: Energy Star products; Energy Star buildings; energy use analysis; hydropower generation data; DOE NEPA documentation, and EPA geospatial data. SmarterHouse: This site from the  American Council for an Energy-Efficient Economy (ACEEE) has information to help you make wise investment decisions for maximum energy savings: Planning Energy Improvements and Home Energy Checklists and quick fixes, with information about Appliances + Energy » Cooking, Dishwashing, Food Storage, Home Electronics, Laundry, Lighting; Home Systems + Energy » Building Envelope, Cooling Systems, Heating Systems, Ventilation and Air Distribution; Water Heating Resources » and more. DSIRE: Database of State Incentives for Renewable Energy with links by state to programs like Residential Renewable Energy Tax Credit and PV Incentive rebates.  This is a comprehensive source of information on state, local, utility, and selected federal incentives that promote renewable energy. National Solar Permitting Database:  A free, online database of solar permitting requirements for cities and counties across the country. State and Local Policy Database:  Sponsored by the American Council For an Energy-Efficient Economy (ACEEE), the database includes comprehensive information on energy efficiency policies currently implemented at the state and local level. The database tracks policy activity across multiple sectors, including state and local governments, utilities, transportation, buildings, combined heat and power, and appliance standards. Users can click on a state or city on the database map to learn more about the specific policies that encourage energy efficiency. Users can also look at a particular policy type and compare the approaches of all states or cities to that topic. Utility Data Access Map:  From DOE, this is an interactive Web platform that enables electric utilities across the country to show both residential and commercial customers, in a simple way, the data they can access on their electricity use. The tool highlights local access to electricity data and allows consumers to compare their electricity data access to others in their state and across the country. The data access maps display different features of consumer electricity data including the time period and timeliness of data--informing consumers, for example, whether their utility supplies same-day electricity use information--and the extent to which the data can be shared. [...]

What is a windbreak?


A windbreak is a row or group of trees, shrubs, or structural elements (e.g. fences) that are used to block and direct the wind. Vegetative windbreaks are used in agriculture to prevent wind erosion or damage to field crops. For homeowners, windbreaks can be used to block harsh winter winds around housing. By planting windbreaks, homeowners can realize a savings in heating bills. The U.S. Department of Energy has more information about Landscape Windbreaks for your home.


Is there a specific type of tree that is good to plant for energy conservation?


Different types of trees can help to conserve energy in different ways. Deciduous trees (trees that lose all of their leaves each fall) save energy in summer by shading houses, paved areas, and air conditioners. Small deciduous trees and shrubs, especially those with low, dense branches, also can serve as effective wind barriers.


Large and small evergreen trees and shrubs save energy by slowing cold winds in the winter. They also provide shade, but since they often have branches near the ground, their shade is most effective when the sun is not directly overhead. Both deciduous and evergreen trees save energy in summer by directly cooling the air. This cooling happens as water evaporates from the leaf surfaces, just as our skin is cooled when we perspire.

Urban Forests: Environmental Benefits


Shade is one of many environmental benefits trees provide. Urban forests are made up of the trees that exist in urban or suburban landscapes. An urban forest is comprised of trees in many settings - in residential and commercial landscapes, along streets and other rights-of-way, and in parks, greenways and set-aside natural areas.  Urban forests have great environmental, economic and social value. Urban forests can moderate the impacts of urban air pollutants.  Trees remove particulates, sulfur dioxide, ozone and other air pollutants that are problems in some cities (4).  Like all forests, urban forests remove carbon dioxide from the atmosphere.   The U.S. Forest Service has developed tools to help planners assess the energy conservation and carbon storage value of urban trees (see Climate Change Resource Center). When properly located, shade from urban trees can reduce electricity use from cooling indoor space (2), and trees can provide habitat for birds and pollinators. The economic benefits of urban trees include increased property values (3), reduced electricity use, and stormwater mitigation. Urban forests are also socially important, because in contrast to wilderness or managed forests, they are the forests that the majority of humans experience every day. Under changing climate scenarios, the environmental benefits provide by urban forests will help mitigate future climate conditions. Warming temperatures will likely increase summer energy cooling demands. Some planning entities are recommending increased urban tree retention policies as a means reduce cooling and heating demands (1).  References Cited1. Climate Leadership Initiative. 2011. Building Climate Resiliency in the Lower Willamette Region of Western Oregon. Accessed 2/3/11. 2. Donovan, G.H. and D.T. Butry. 2009. The value of shade: Estimating the effect of urban trees on summertime electricity use. Energy and Buildings. 41:662-668. 3. Donovan, G.H. and D.T. Butry. 2010. Trees in the city: valuing street trees in Portland, Oregon. Landscape and Urban Planning. 94:77–83. 4. Nowak, D.J., D.E. Crane, and J.C. Stevens. 2006. Air pollution removal by urban trees and shrubs in the United States. Urban Forestry & Urban Greening. 4:115-123. For more on Forest Management Types: Forest Wilderness Managed Forests Wildland-Urban Interface (WUI) Plantation Forests Written by Amy Grotta   [...]

Guide wind - Maximize summer cooling



Strategically positioning vegetation in landscapes can maximize energy benefits and save money for homeowners, commercial properties and public facilities. Vegetation can be placed within the landscape to manipulate air movement by

  • obstruction,
  • guidance,
  • deflection, and
  • filtration.

Use vegetation to obstruct or block undesirable winds by arranging dense plantings at a 90º angle to the prevailing winds. Vegetation barriers can be single or multiple rows of trees and shrubs. The air speed is affected by the density of vegetation, the distance the vegetation is from the home or business being protected, and the height of the vegetation.

Wind can be guided during the summer months by designing walls of vegetation to direct air to sites where maximum cooling is desired (figure 1). By directing wind through strategically placed vegetation to constrict airflow, designers create a vortex effect. Wall(s) of vegetation can be used also to deflect wind away from targeted areas. Implementing the same concept of using vegetation as a barrier, the air is guided away from the targeted area rather than blocking it entirely. Additionally, windbreaks can be designed to slow the speed of the wind by filtration when some, but not all is desired.


Figure 1. How to create an effective windbreak. Image Credit: Landscape for life, (used with permission).

The key to using vegetation for energy savings will depend on:

  • Appropriate site analysis
  • Effective design of the area
  • Selection of the right tree for the right place

See additional resources about windbreaks, tree placement and Urban Tree Benefits.


Keep the Happy in Your Winter Holidays: Stay Warm and Safe



Most of us look forward to the fall and winter holidays as times for celebrating, feasting, homecoming, and gathering, connecting with our deepest spiritual roots, saying goodbye to the old year and ringing in the new.

Yet the record shows a season of Menorahs and other celebratory candles igniting the drapes, Butterballs flaming up from their fryers, improperly installed woodstoves and combusting Christmas trees destroying homes.

We’re dizzy with busyness, easily distracted, preoccupied with changes to our normal routines and habits. It’s cold in many parts of the nation, so we’re revving up furnaces, firing up woodstoves, hauling out space heaters. Blizzards and ice storms can bring lengthy power outages, so we’re lighting kerosene lamps, oil lamps and candles.

Kathy Hopkins, a University of Maine extension educator, advises and reflects the concerns of people in cold northern states such as Maine.

“When the price of oil spikes, people often haul out an old space heater or woodstove to supplement their central heat,” she says.

“Space heaters create a real danger when people plug them into an extension cord that can’t handle the load, and they overheat, which can cause a fire.

“Especially for people new to wood heating, we urge them to have the local fire department inspect it to see it’s installed properly and also that they have a safe, working chimney. For wood heat, we also recommend installing a stack (stovepipe) thermometer and learning how to use it,” says Hopkins.

“And of course, with space heaters, woodstoves, and open flames such as candles, it’s also important to keep combustible materials at least three feet away.”

In fact, Christmas week is notorious for generating candle-related house fires. The Allstate Insurance Company notes that the median cost for candle fires is almost $50,000.

And do take special care with those Christmas trees, real or artificial. Allstate data peg the median cost of a claim for a Christmas-tree fire at more than $100,000. In fact, a fire involving an artificial tree resulted in the most costly claim in recent years: $4.4 million.

Learn more:
Home Heating Safety, University of Maine Extension Bulletin
Safe, Efficient Woodburning, Tips from the University of New Hampshire Cooperative Extension
Winter Fire Safety Tips, Good information from the Ohio Committee for Severe Weather Awareness
Allstate Winter Holiday Safety Data & Tips, Interesting data from Allstate’s claims database and a survey of policyholders.


Released December 26, 2013

Source: Kathy Hopkins, University of Maine Extension,

Writer: Peg Boyles, eXtension,


Is mold a health issue inside the home?



Mold in the home can be a health hazard if it's allowed to grow and isn't handled properly.

The type and severity of health effects depend upon:

  • the level and duration of exposure
  • sensitivity of the person
  • the type of mold and toxin it may produce
  • and other factors that can increase the health hazard (such as smoking).

People most likely to experience health problems from mold include:

  • children
  • elderly
  • people with suppressed immune systems
  • people with asthma or allergies

Most molds are allergenic and can trigger asthma attacks in susceptible people. Some molds can emit mycotoxins in certain conditions.  The Centers for Disease Control indicate that for "people sensitive to molds, exposure can cause symptoms such as nasal stuffiness, eye irritation, wheezing, or skin irritation. People with serious allergies to molds may have more severe reactions such as fever and shortness of breath. Some people with chronic lung illnesses, such as obstructive lung disease, may develop mold infections in their lungs."

For more information about mold and moisture, its health effects and ways to eliminate, clean and remove mold, you can also visit The Environmental Protection Agency's site on mold. 


Climate Mitigation by Urban Forests


  Planting trees in urban areas can help mitigate carbon dioxide levels because trees can sequester carbon and offset some energy use for cooling, as some studies have illustrated in California.  The California Global Warming Solutions Act of 2006 (AB32) requires a reduction in greenhouse gas emissions to 1990 levels by 2020. This amounts to a reduction of 173 million metric tons from the level projected for 2020. Aerial photography revealed 242 million potential sites for planting individual trees in the 21 California cities considered (McPherson and Simpson 2003). If 50 million trees were planted, they would sequester about 4.5 million metric tons of carbon dioxide (as 1.2 million metric tons of carbon) every year. If they were planted strategically to shade east and west walls of residential buildings, they would reduce energy use from air conditioning by 6,408 gigawatt-hours, equivalent to reducing carbon dioxide emission by 1.8 million metric tons annually. This assumes a 75 percent survival rate of seedlings after 15 years. Combining the carbon sequestration by trees with the energy savings that strategic planting would allow, the estimated total carbon dioxide reduction is 6.3 million metric tons a year. This amounts to 3.6 percent of the state’s goal of reducing the emissions of this greenhouse gas by 173 million metric tons. That is about the same as would be obtained from retrofitting homes with energy-efficient electrical appliances. The annual cooling related to California’s existing 177 million existing urban trees already provide enough cooling that the annual energy savings would power about 730,000 homes. This includes reducing summer peak demand by about 10 percent (about 5,000 megawatts), which helps to avert potential power outages. References cited: McPherson, G., and J.R. Simpson, 2003. Potential energy savings in buildings by an urban tree planting programme in California. Urban Forestry and Urban Greening. 2: 73-86. Related to Climate Mitigation by Urban Forests: Urban Forests and Climate Change Trees and Local Temperature Urban Forests and Heat Waves Cost-Benefit Approach to Urban Forests Designing Urban Forests Urban Forest Project Protocol Calculating Carbon Drawdown by Trees Urban Forestry and Carbon Storage Preparers: Greg McPherson, Jim Simpson, Dan Marconett, Paula Peper, and Elena Aguaron, Center for Urban Forest Research, Pacific Southwest Research Station. Adapted from: McPherson, E.G.; J.R. Simpson, P.J. Peper, and E. Aguaron. 2008. Urban Forestry and Climate Change. Albany, CA: USDA Forest Service, Pacific Southwest Research Station. .  Adapted by Melanie Lenart, University of Arizona [...]

Time for Trees to Provide Energy Conservation Benefits?


It is possible to plant a tree that within a few years will provide energy conservation benefits. The length of time between planting and energy conservation savings is a function of the following factors: Tree species (fast- or slow-growing) Site (soil qualities such as fertility, moisture, compaction) Desired energy conservation function (windbreak or shade) Size and position of the structure for which energy conservation is desired Some fast-growing tree species, under ideal growing conditions, may begin providing energy benefits (deflecting winds or casting shade) in as few as 5 years.  In other cases, slower-growing species good for long-term energy conservation may take 20 years or more to begin providing benefits. Photo Credit: Raina Sheridan      In general, the faster growing the species, the shorter the lifespan. Hybrid Poplar, for example, is a sterile cross between two Poplus species such as Cottonwood (Populus deltoides) and Black Poplar (Populus nigra). This is a very fast-growing tree that on good soils grows an average of 4 – 6 feet a year (Demeritt, 1981), but may have a typical lifespan of only 10 years before succumbing to disease.  Fast-growing trees such as this could be used to gain more immediate energy conservation benefits, but should be considered temporary plantings. At the same time as planting the fast-growing species, longer-lived species should also be planted in position to take the place of these temporary trees. Species is not everything. The growth rate of any tree is directly related to the overall condition of the site. Ideal soil conditions (optimum fertility, moisture and drainage) will maximize growth rates. While this is true for all trees, some are more sensitive than others to site limitations. For example, red maple (Acer rubrum) is one of the most common species in the United States, partly because it tolerates such a wide variety of sites. Black walnut (Juglans nigra) can be a fast-growing tree when planted on deep, well-drained soils such as a floodplain. If planted on shallow soils, it may survive but grow slowly for many years. Additionally, young trees tend to be very vigorous growers. As an example, oak trees tend to have a moderate growth rate, but as young, newly planted trees, they can quickly grow in height and width on favorable sites. Finally, factors such as the size of the structure for which energy conservation is desired, its position within the landscape, and the conservation function wanted may influence how long a tree needs to grow to begin providing energy benefits. Smaller structures, such as a small house or shop, can begin to receive cooling shade from a tree that is only 10-20 feet high. If this same house is downhill from the trees casting shade, the benefits will be even sooner. Likewise, if windbreaks are desired, there are many fast-growing species that may be able to obtain functional heights in just a few years, even sooner if the topography of the planting area is higher than the structure. For the most part, conservation benefits from trees increase with time, as the tree or trees grow in height and spread. Trees, however, have a limited life span and obviously stop providing energy benefits when they die. As trees approach over-maturity, energy benefits are maximized, but risk of tree/branch failure is also increased. When it comes to reaping energy conservation benefits from strategically placed trees around your home, barn, or business, time is money, but don’t forgo future benefits at the cost of procrastination. Whether the structure you desire to shelter from wind and/or sun is one that you think you’ll “live in” for a long time or not, the time to plant a tree is now. We have made at least a start at discovering the meaning of human life when w[...]

Basic Information to Consider for Home Water Heating


Reviewed and Revised on 01/03/2014 Energy Usage in Home Water Heating  Closed-combustion water heater with power vent fan Water heating is often the third largest energy expense in your home, after heating and cooling. It accounts for 15-25% of your utility bill. It’s not hard to see why --  family of four, each taking a 5-minute shower every day using inefficient shower heads, can use 700 gallons of water in one week. This is enough for a three year supply of drinking water for one person. There are simple ways to reduce the amount of money you spend on heating water including insulating your water heater and pipes; reducing the amount of hot water used by taking shorter showers, washing clothes in cold water, and only running full loads of dishes and clothing; and turning down the thermostat on your water heater to 120 degrees. Other more complicated methods include: Correct Sizing of the Water Heater  A water heater should be of large enough size that it can provide hot water during the household’s busiest times of the day. To determine this, first consider the size of your family. A home with two adults could use up to 30 gallons of hot water in an hour, whereas a family of six may use 70 gallons in an hour of peak use. A water heater that is too small won’t keep up with your family’s hot water demands. However, a water heater that is too large will increase the standby losses (the amount of heat the water heater loses as it stands waiting to be used). Standby losses can vary by model. In addition, evaluate the need for an on-demand water heater. When the current water heater location is a long distance from the source of hot water use, consider an on-demand water heater located at that point of use. The US Department Of Energy's website provides detailed guidance on how to size different kinds of water heaters. Carefully Selecting the Water Heater's Location If building a new home, try to locate the water heater close to high hot water use areas such as bathrooms, the laundry, and the kitchen. This will mean a shorter pipe “run” with less loss of heat through pipe walls and hotter water arriving sooner at the tap. Maintaining Your Existing Water Heater It is important to maintain your water heater to improve it's efficiency. First, you should flush it out quarterly, semi-annually, or annually depending on the water hardness. This will reduce the build up of debris at the bottom of the heater that can reduce heat transfer and shorten the life of the water heater. Next, you can install pipe insulation on the inlet and outlet pipes to reduce standby losses. Lastly, you can insulate the tank, but be careful not to get too close to the vent pipe, restrict combustion air supply, or cover any controls.   On-demand water heater   Finding a New Energy Efficient Water Heater There are many ways to heat water. If you are in the market for a new water heater, first check the U.S. Department of Energy’s (DOE) web site for information on energy efficiency, fuel types, new technologies, and availability. You might also check with your utility company, as they may offer rebates or incentives for certain types of energy efficient water heaters. Keep in mind that your choice of water heater and its fuel source will depend, in part, on where you live and the type and size of space available. When shopping, read the EnergyGuide label, and look for the ENERGY STAR® symbol. Read more about ENERGY STAR products and water heaters. When shopping for an energy efficient water heater, keep in mind your hot water needs. Also, don’t forget to take into account water conservation measures, like installing low-flow shower heads. For additional information go to:[...]

How to Keep Warm and Safe at Home


Reviewed and Revised on 10/15/2013 Home Heating Safety Tips Fires and accidents caused by home heating equipment are largely preventable if you clean, maintain, and use equipment properly. By reviewing general safety tips, including those related to heating emergencies and those specific to electric and kerosene space heaters, wood stoves, and fireplaces, you can avoid heating accidents. Heating devices can be extremely dangerous if you use them incorrectly. Improper use of home heating equipment can cause death from fire, lack of oxygen, or carbon monoxide poisoning. However, home heating equipment accidents are largely preventable if you operate equipment properly, and follow basic safety practices. Safety Tips: Your home should have battery-operated smoke detectors on each floor. Check batteries monthly, and replace them at least annually. Consider an electric operated smoke detector with battery back up for extra safety. Install carbon monoxide (CO) detectors. CO is a poisonous gas that is odorless and colorless. Home heating and cooking devices that are combustion equipment can be sources of carbon monoxide. Know the signs of carbon monoxide poisoning, which include headaches, nausea, stomach pain, dizziness, and burning in the eyes and nose. If you think you have a carbon monoxide problem, open your doors and windows immediately. Leave the area and contact a professional heating contractor to evaluate and repair faulty appliances. If someone has symptoms, is ill, or unconscious, call 911. Photo of a fire extinguisher Keep type ABC multipurpose fire extinguishers on hand and near heating appliances. Make sure that everyone in your family knows how to use a fire extinguisher. Everyone in your home should know and practice a fire escape plan. Make sure everyone knows two ways out of every room. Each year, have a qualified heating contractor inspect, clean, and maintain your furnace, boiler, water heater, vents, and chimney connections. Change or clean the furnace filter at recommended intervals. Make a habit of checking chimneys, flues, and vents for leakage and blockage by creosote and debris. Leakage through cracks or holes could cause black stains on the outside of the chimney or flue. These stains can mean that pollutants are leaking into the house. If a wood stove is used, be certain that manufacturer's requirements for clearances to combustible surfaces have been adhered to. If you have a heating appliance that has a direct vent through the side wall of the house, keep it clear of snow and leaves. All combustion devices need adequate air for complete combustion of the fuel and to safely vent pollutants up flues, stovepipes, and chimneys. Never block combustion air or ventilation openings. Make sure your appliances are inspected for adequate combustion air and proper venting. When exhaust fans, dryers and other devices draw air out of the home, they create negative pressure that can overpower the natural draft of chimneys and vents and pull combustion fumes back into the home from the chimneys and vents. This is commonly referred to as combustion spillage or backdrafting and is potentially a very unsafe condition. If this occurs, it will be necessary to provide for entry of additional outside air in the vicinity of the affected appliance. Never operate more than one heating appliance through a single flue. Flues are usually designed and built for a specific appliance that was originally built into the structure. Do not obstruct heating ducts, cold air returns, or any heat source. Keep furniture away from baseboard heaters. Never use unvented space heaters or hearth products as a heating source. If used for temporary or emergency purposes, you must explicitly follow manufacturers ins[...]

Energy Efficient Home Freestanding Stoves/Ranges


Reviewed and Revised on 11/07/2013 Energy efficient, multifunctional, and stylish freestanding stoves/ranges Since the kitchen is generally the hub of the home, consumers want it to offer an uplifting feeling of optimism. Energy efficient lighting, cabinetry, colors, and appliances combine to create the perception of comfort, security, and that overall good feeling offered in the kitchen environment. Smart consumers also want eco-friendly, energy efficient appliances, not only saving for themselves, but also for future generations. Today’s manufacturers, responding to consumer demand of freestanding stoves or ranges, have expanded lines to offer energy efficient, stylish models with a wide variety of colors, sizes, and surface materials. Although they are not ENERGY STAR rated, ranges are continually appearing on the market that can save energy, money, and time. Stove tops can include six or more burners, a warmer, a grill, a non-stick griddle, and hybrid types such as radiant/induction heat. They can have optional back panels. However, select only the features that you need and will use to avoid excess material use and energy use. Select an oven size that is suited to most of your needs; larger ovens generally will use more energy. Gas stoves Image of Gas Stove/Range Gas stoves consume less energy than electric stoves, but must be used with a vent hood drafted to the exterior through the roof, eaves, or wall to remove carbon monoxide, other combustion pollutants, as well as cooking moisture and odors. There are three types of gas burners: conventional burners with standing pilots, conventional burners with electric ignition (the most common) and sealed burners, where the burner is fused to the stovetop. Sealed burners are easier to clean. Electronic ignitions, rather than pilot lights, are more energy efficient and eliminate the continuous low-level pollutants from pilot lights. Operation and maintenance issues may include lack of enough air to burn fuel properly, maladjusted burners, and misuse as a room heater. Look for a certification label such as CSA group label. Call your appliance service representative or local utility company to adjust the burner if there is a lot of yellow or orange in the flame. Although a blue flame is typically considered an indication of efficient combustion, occasionally it may be producing excess carbon monoxide. Electric stoves Photo of a freestanding electric stove/range in a kitchen Electric stoves, in addition to exposed coils (the most common), are available with an easy clean, smooth glass-ceramic cook surface. Radiant heat or halogen heat elements provide heat under the glass-ceramic surface, which in turn heats the cookware. To save energy, turn off the burner a few minutes before the end of cook time. The burner, still hot until it cools off, will continue cooking the food in a covered pot. Stove tops with induction elements under a glass-ceramic surface use about half the energy of a typical electric stove with coils. Induction heating is the transfer of electromagnetic energy to directly heat iron and steel cookware, so it does not directly heat the smooth top surface. The surface is cooler to touch than all other type range tops, which is a safety benefit. Induction burners cannot heat aluminum or ceramic cookware unless they have an iron content layer, so hybrid stovetops with both radiant and induction heating offer the flexibility of energy-saving, cool, safer induction burners along with burners that can use non-iron content cookware. Like gas ranges, electric stoves should also be vented to the outdoors to remove moisture and other cooking pollutants. Other options In convection ovens, hot, circulat[...]

Phantom/Standby Energy Use by Home Electronics and Appliances


Reviewed and Revised on 11/04/2013 Consumer electronics and appliances amount to about 15% of a home’s utility usage. Did you know these modern conveniences can cost you a lot of money even when they are turned off, but still plugged in?   Today an average American home is brimming with consumer electronics and appliances- televisions, DVD players, stereos, kitchen gadgets, etc. Most of the times these appliances stay plugged in, and are just turned off (but not unplugged) when not in use by a homeowner. They draw power however because they are not unplugged. The power so drawn is called “phantom,” "vampire," "leaking energy," or "standby" energy use. Products with clock displays, remote controls, and other features also draw phantom power 24 hours a day when plugged in. A simple way to figure out if your appliance is drawing power is to touch the plug (transformer). If warm to the touch, it is drawing power. The amount of power drawn by an individual product may not be much (a few watts to up to 40 watts), but since a typical American home could have about such 40 products which draw phantom power, cumulatively they call can be responsible for up  to 10% of the power bill. Here are several ways to reduce the phantom energy consumption of appliances: Use a high quality power strip as a central power supply for clusters of computer, video (TV, DVD, video games, etc.), or audio products (receivers, amplifiers, etc.), so everything can be switched off with one action when the equipment is not in use. Do not overload a circuit with too many items plugged in, as it is dangerous. Most circuits in a home are 15 AMPs, but only use 75%, which is about 11 AMPs. Look at the amount of AMPs that each item uses. Heating products use more AMPs than the products. Contact an electrician or your local utility company if you need more information about AMPs. Photo of power strip Sometimes it is not possible or convenient to keep on turning off the power strip when the plugged in appliances are not in use, say at work when stepping out for a few minutes, thinking of a problem or discussing something with a colleague etc. In such situations Smart Power strips can be very useful to help turn off the plugged in equipment. Smart Power strips are of three kinds-  timer equipped, occupancy sensing and current sensing (Energy Star, 2013).  Timer Equipped: As the name suggests the power outlets of these strips are controlled by programmable timers. One can set times of day or night when one would like the plugged in devices to be automatically turned on/off. Occupancy Sensing: The power outlets in these strips are sensitive to motion. The plugged in devices automatically gets turned off in response to motion sensed after a certain period of elapsed time. Current Sensing: These strips have a master power outlet and rest of the outlets are controlled by this outlet. Depending upon if the device plugged in master outlet is turned on or off the other devices get automatically turned on or off. For e.g. if the computer plugged in the master outlet is turned off, the printer or scanner plugged in controlled outlets automatically get turned off. Unplug chargers for cell phones and power supplies (the black cubes that convert AC power to DC) when the equipment is fully charged or not in use. Enable power management features on your computer, monitor, and other office equipment. Avoid using a screen saver on your computer’s monitor; allow the monitor to switch to “Sleep” mode, "Power-down" function, or turn it off when it's not in use. Reference: Energy Star. (2013). More IT Energy Saving Tips. Retrieved on November 05, 201[...]

How to Increase the Efficiency of Your Home Refrigerator


Reviewed and Revised on 11/07/2013  Even if you aren't able to replace your existing refrigerator with a new model, there are some things you can do that can help your refrigerator run more efficiently.   Even if you aren't able to replace your existing refrigerator with a new model, there are some things you can do that can help your refrigerator run more efficiently. Below are some energy saving ideas: Check the temperature For energy savings and food safety, experts state that ideal home refrigerator/freezer temperature is 37-40 degrees for the refrigerator and 5 degrees for the freezer. If you have a separate freezer, it should be 0 degrees. Allow for air circulation To allow air to circulate around the condenser coils, leave a space between the wall or cabinets and the refrigerator or freezer and keep the coils clean. This is very important as dust accumulation blocks heat release and makes the compressor run longer. Inspect the door seals Loose seals allow for air leakage. Refrigerators without magnetic seals can be checked for tightness using a dollar bill. Close the refrigerator door on a dollar bill so that it is between the seal and the unit. If the bill slides out easily, or falls out, your seal isn't tight. Be certain to check at the top, sides and bottom of the door. Door seals can be replaced. Consider the unit's location Position your refrigerator away from heat sources such as a heating vent, an oven, a range, a dishwasher, or direct sunlight from a window. The extra heat will make the compressor work harder. More importantly, there must be adequate circulation around the compressor and condensing coil so that heat can escape. Defrost regularly Manual defrost models use less energy than automatic defrost; however, in order to keep them running at maximum efficiency they should be defrosted regularly. When ice builds up inside the unit, it causes the compressor to run longer in order to keep the unit cool. This increases energy use. Minimize openings Opening and closing the refrigerator and freezer door allows cool air to escape. Know what you are going to get out of the refrigerator/freezer before opening. Help children make decisions as well. Consider food storage A full freezer operates more efficiently than one that isn't. When storing foods, make certain they are in tightly covered containers and allow foods and liquids to cool before putting in the refrigerator/freezer. Drinking water Use your water feature instead of drinking bottled water. It will save you money and help the environment at the same time. Rethink the second refrigerator Many families have a second refrigerator, usually located in a utility room, basement, or garage. While a second refrigerator may come in handy on occasion, it can be expensive to run -- especially if it is an older model. Think carefully about what you store in this refrigerator and determine if the extra storage for the items is worth the additional yearly cost ($100 or more) of running the unit. Other related articles you might be interested in:How to Recycle Your Old Home RefrigeratorBuying Energy Efficient Home Refrigerators and Freezers See all Home Appliances and Electronics articles. [...]

Using Landscaping Vines and Structures to Reduce Home Energy Costs


Reviewed and Revised on 10/17/20

Vines, shrubs, and some trees can be used as espaliers (plants trained to grow flat against walls) can be used to protect home walls from heat and cold. The plant foliage provides a sort of insulation against summer heat and cold winter winds. It can also help to reduce noise. Vines like English ivy are not recommended because they cling to masonry and wooden surfaces and can damage your house. Vines that twine and that will cling to a trellis placed near the house are generally a better choice since they don’t damage the structure. The trellis also allows for an air space of cooler air. Leaving an air space next to the house by planting vines on a trellis is especially important in humid climates to prevent moisture buildup. Fast growing vines such as morning glory or moon vine can provide needed summer shade.

Arbors, slatted wooden structures, and awnings can be effective on the east and west sides of the house. Arbors with deciduous vines growing on them provide additional shade over an outside area while blocking the sun's rays from hitting sections of the house. In the winter months the leaves will drop off the plants and more light and warmth will reach the house.

Adapted from: Landscaping for Energy Conservation by William C. Welch, Extension Landscape Horticulturist, Texas Agricultural Extension Service. Accessed October 14, 2009

This article was reviewed by Gail Hansen, Environmental Horticulture Department, University of Florida

Compact Fluorescent Lighting -- CFL


Reviewed and Revised on 11/13/2013 How much can I save by switching to Compact Fluorescent Lamps/Light bulbs? On an average lighting represents 10-15% of a home's electricity bill. Switching from incandescent light bulbs to compact fluorescent lamps/lightbulbs (CFLs) is the simplest way to save on this bill.  A CFL bulb uses only 1/4th of the energy used in a incandescent bulb and last 10 times longer. It does cost about $2 or more in comparison to incandescent bulbs however, if bought at a regular retail store. If bought in bulk from ware house clubs (Costco, Sam's ), which are present all over the U.S., depending upon the wattage, these can be as low as 50 cents a piece. Thus, one can easily save the initial cost of the bulb several times over its entire life time.  On an average, each CFL bulb can save more than $30 in electricity costs over its lifetime, and prevent more than 450 pounds of greenhouse gas emissions in the atmosphere.For the biggest energy savings, replace incandescents or halogens with CFLs in the rooms you spend the most time in, such as the family room, living room, and kitchen. It is estimated that if every household in the U.S. changed just one incandescent light bulb with an ENERGY STAR qualified CFL, the nation would save enough energy annually to light more than 2.5 million homes, and prevent greenhouse gases equivalent to the emissions of nearly 800,000 cars. What’s different about ENERGY STAR CFL fixtures? CFL lamps and bulbs that have earned the ENERGY STAR label combine quality and attractive design with high levels of energy efficiency for homes. All qualified fixtures: Use one-fourth the energy of traditional lighting. Last at least 10,000 hours (about seven years of regular use). Distribute light more efficiently and evenly than standard fixtures. Come in hundreds of decorative styles including portable fixtures—such as table, desk, and floor lamps—and hard-wired options such as front porch, dining room, kitchen ceiling and under-cabinet, hallway ceiling and wall, bathroom vanity fixtures, and more. Deliver convenient features such as dimming (to be dimmable, the fixture must have a dimming ballast) on some indoor models and automatic daylight shut-off and motion sensors on outdoor models. Can be found at most home centers, lighting showrooms, and specialty stores. Carry a two year warranty—double the industry standard. How do “regular” light bulbs work? Incandescent bulbs, or “regular” bulbs, consist of finely coiled wire filaments in a glass bulb filled with an inert gas. The wire’s resistance to the flow of electricity causes it to become hot enough to glow. About 90% of the energy used by an incandescent bulb becomes heat and only 10% becomes light. How do fluorescent lights work? A fluorescent bulb has a phosphor coating on its inner surface that converts ultraviolet energy into light. Over time, molecular vibrations inside the tube cause the phosphor coating to vibrate off. When the phosphor is used up, the tube won’t light. Why do fluorescent bulbs use less energy? More of the energy of a fluorescent bulb is converted into light and less into heat. By producing less heat (about 75% less heat for an ENERGY STAR qualified CFL), fluorescent bulbs also save on air conditioning costs. You save twice! What is a ballast? A ballast is the part of a fluorescent bulb that excites the phosphor molecules. Depending on the bulb, it can either be attached, as it would be in CFLs, or it can be part of the fixture, as it would be with fluorescent tubes. Ballasts[...]

Types of Building Systems for New Home Construction


Reviewed and Revised on 10/29/2013 Below are brief descriptions of alternative building systems used in residential construction. Important energy related features are specifically mentioned. Standard Framing. Most homes in the USA are wood framed with 2x4 lumber spaced 16 inches on center. Typical practices include using extra studs at corners to support wallboard, double top plates, uninsulated headers made from double 2x10 lumber over all windows, doors, and other traditional methods. OVE/Advanced Framing. Optimum Value Engineering spaces and aligns floor, wall, and roof framing at 24 inches on center (2-ft. modules) and uses framing techniques that eliminate lumber not necessary for load-bearing purposes. Examples include two-stud corner framing, single top plates because of the aligned framing, and insulated headers sized for the load-bearing need. OVE reduces materials and labor. It also improves energy efficiency by displacing lumber with insulation, and it reduces construction waste. When using 2x6 lumber, advanced framing provides space for higher insulation levels (R-19 to R-21) and meets standard building codes; however, some OVE framing techniques could be excluded by some locally established codes, in high wind zones, or if it’s unfamiliar to local building officials.   OVE Advanced Framing (Adapted with permission from Builder's Guide: Hot-Humid Climates by Joe Lstiburek, Building Science Corporatation)   SIPS. Structural Insulated Panel Systems combine structural framing and insulation into one product. They consist of rigid foam insulation sandwiched between two exterior structural panels, or skins, adhered to the foam. The skins are most commonly oriented strand board (OSB) panels, but they can be plywood, metal, a fiber-cement, or other materials. SIPS are available in 4x8 feet and larger panels, up to 24 feet long and 4-12 inches thick. They can be cut on site, but are usually ordered from the factory as a package, ready to assemble with all window and door openings precut, and channels through the foam core for wiring.   SIPS have high strength characteristics and can be designed to withstand winds up to 160 mph. They have excellent energy efficiency performance because of the nearly uninterrupted R-15 (4.5 in. panel) to R-48 (12.25 in. panel) insulation and airtight construction that can result when using SIPS for both walls and the roof or ceiling. With precut panels, installation time can be less than half that of stick framing, with little construction waste.   Structural Insulated Panel System (SIPS)       Masonry Construction. Masonry wall homes (built with steel-reinforced concrete blocks or bricks, cast-in-place concrete, or pre-cast tilt-up concrete panels) are uncommon in Louisiana, but common in Florida and other hot, humid climate areas. “Brick homes” are usually wood frame with a brick veneer, so are not actually masonry construction. Masonry walls are sometimes combined with wood or steel framing for some parts of the building, depending upon the cost and availability of skilled labor. Masonry walls are typically insulated on the inside with rigid foam insulation and have a stucco exterior finish. Since this is a barrier and “reservoir” or water storage building system, both the interior and exterior should be vapor permeable. Masonry is insect and fire resistant. AAC. Autoclaved Aerated Concrete is a pre-cast concrete that has been chemically expanded (with gas bubbles) and steam cured under pressure in an autoclave to form building blocks or panels. This [...]

Tips for Energy Savings by Installing Home Window Treatments


Reviewed and Revised on 11/13/2013 Window treatments can help improve the energy efficiency of windows in your home. However, other improvements such as: caulking, weatherstripping, air sealing,  insulating attics can have a higher impact on reducing your home energy use and should be done before considering window treatments. Window treatments are generally especially helpful, If there are problems with solar heat gain (sun's heat travelling through a window and heating the inside of a home), feeling cold from losing body heat (feeling chilly in front of windows) and with drafts through the window. Some window treatments will reduce heat losses through the glass only, while other block drafts as well.  Roman shades help trap air In cold weather:   window treatments need to have insulating properties to reduce the U-factor (increase the R-value) of the windows. The U-factor is the rate of heat loss from the window, so in this case, you want to keep heat from being lost from the inside of the home to the outdoors. In hot weather:  window treatments are needed to reduce the solar heat gain. For exterior applications these could include sunscreens and awnings; and interior treatments - window films, white/light colored shades, blinds, and shutters. Additional options could be draperies, insulative panels, high-reflectivity films, mesh window screens and storm panels. In order for a window treatment to achieve the intended insulative value (i.e. R-value which measures the ability of that insulation to resist heat travelling through it) a tight seal all around the window treatment is needed to trap air. Multiple layers of shades and/or drapes, and shutters can help to achieve this effect. A tight fit close to the window is needed as well. Cornices or shelves at the top of the window treatment help trap air and reduce convection air currents. Convection is the naturally occurring process in which warm air rises and cool air sinks. Draft stoppers or cloth tubes filled with sand help block drafts at the bottom of the window treatment. Some treatments can be fit into metal or plastic tracks for a tight fit. Select window treatment materials that trap air. Using firmly woven heavy fabric reduces air passing through the fabric. Adding a white or light colored lining either as a separate lining or with the window treatment helps reduce heat loss in the winter and heat gain in the summer. Inside casement mount White or light colored window shades hung inside the window casement or frame rather than on the window trim or frame are more effective in reducing heat gain (in summer) and heat loss (in winter). Insulated Roman shades filled with fiber batting and layers of fabric mounted inside the window frame are also energy efficient. Open weave fabrics, reed, or bamboo shades or treatments filter direct sunlight, but have little insulation value. Window blinds with multiple slats allow air movement, thus providing little insulative value. However, blinds are effective in reducing solar heat gain. Things to be careful about when buying/installing window treatments: 1. R-value: Pay attention to the R-value of the window treatment. Ask how this was determined, under what types of testing conditions, and if it is for the total treatment or at the center of the treatment. Ask if it is an estimate, or tested in a laboratory. Installation and management of the treatment will impact its energy insulating effectiveness. 2. [...]

Tree Planting for Lower Power Bills


Whether it is winter or summer, trees can help you save energy at home.    Shade for Savings   Did you know that only 17% shade over your house during the day translates to a savings of 10 dollars a month on your power bill? Additionally, increasing that same shade to 50% will decrease your power bill by an additional $20 per month.  For those without trees, it takes time to plant a tree and generate this shade.  However one study estimates that within 5 years of planting you can realize a 3% energy savings and by 15 years that savings can increase to 12%.   So whether you have shade or are looking to generate some tree shade, read-on to learn the key to success:  Put the right tree in the right place. The Cooling Effect of Trees: Trees naturally cool the environment.  Through the process of transpiration, similar to that of evaporation, trees lose water vapor from their leaves.  This allows not only for minerals and water to move throughout the tree, but also has a cooling effect on trees and their surrounding environment.  It is similar to our process of perspiring and how it cools our skin.  One study estimated that the net cooling effect of a young healthy tree would be equivalent to 10 room-size air conditioners running for 20 hours a day.  By contrast concrete, asphalt and other impervious surfaces in the urban environment absorb heat, causing for this heat to build up and dissipate even well after dark. As a result cities tend to be several degrees warmer than the surrounding countryside.  This is referred to as the Heat Island Effect.  However, there is hope for the urban environment by introducing trees and putting them to work.  Urban trees can not only mitigate higher urban temperatures but reduce cooling and even winter heating bills. Planting Trees for Summer Shade: Radiant energy from the sun heats home surfaces such as walls, roofs and windows forcing air conditioners to work harder.  This drives energy consumption and power bills up.  While good insulation will help mitigate this problem, shade from surrounding trees can further conserve energy, especially for older homes with outdated or limited insulation. Selecting deciduous trees, or trees that lose their leaves during winter, is ideal for energy conservation.  These trees will provide shade during hot summers and only minimal shade during cold winter months when the sun’s heat is desirable.  The key to maximizing energy conservation is carefully placing trees to provide shade to the home from morning and afternoon sun.  To protect from morning and afternoon sun plant trees to shade east and west facing walls and windows. For both east and west plantings select a combination of small and large trees.  Small trees will providing shade during early morning and late afternoon when the sun’s angler is low on the horizon.  By contrast the larger trees with a mature height of 25 feet or more will provide coverage in both late morning and early afternoon when the sun is higher in the sky.  Trees should also be located on the south and southwest sides of the house to provide summertime roof shading.   These trees should have high spreading crowns capable of shading the roof.  Avoid smaller trees or trees with excessive lower branches in this location as it will cause excessive shade during winter months, even if deciduous. Planting trees to shade the air conditioner unit can also conserve energy.  Trees and their branches should be at least several feet away from the units to allow for easy airflow.  R[...]

Thermostat Settings for Conservation and $$ Savings in Home Energy



Reviewed and Revised on 11/12/2013



Closely managing your thermostat is an easy way to increase your energy and $$ savings.

  • In the summer, set the thermostat as high as you can while still maintaining comfort.
  • In the winter, set the thermostat as low as you can while still maintaining comfort.
  • If you have central air conditioning and heating, keep the fan switch on “auto.” The exception is for multistory homes where temperature stratification is a problem between the upper and lower floors; leaving the air handler running can reduce the temperature difference, and let you use less heating or cooling energy while keeping all parts of the home comfortable.
  • (image)
    Image of a programmable thermostat
    For heating and cooling systems other than heat pumps, manually set the temperature even higher (in summer) or lower (in winter) if you are going to be away from the residence for four hours or more. The longer the temperature adjustment period, the more you save. It will not take long to heat or cool your house or apartment back to your preferred temperature when you return.
  • If you are in a hot and humid climate, you may not want to raise the temperature setting too much, because humidity problems may occur. The air conditioner helps remove moisture from the air.
  • Instead of manually adjusting the thermostat, you may decide to install a programmable thermostat. A programmable thermostat will allow you to set different temperatures at different times of the day. The temperature will automatically adjust during the times you are home and the times you are away. This will save you money. A heat pump requires a specific type of programmable thermostat.
  • For each degree you raise your thermostat (in summer) or reduce (in winter), you may be able reduce your heating or cooling costs on average by 2-3%.

For more information on programmable thermostats consult the link Thermostats and Control Systems.  You can find additional information on thermostat settings at Energy Savers.

Selecting Energy Efficient Windows for Homes


Reviewed and Revised on 11/13/2013 Why Energy Efficient Windows? The Costs and the Benefits.  Your windows typically provide you with a view, ventilation, shelter, and light. They may also be costing you loss of energy, hard earned dollars, and comfort. Inadequately insulated windows and doors can cost up to 30% a homes' energy dollars. Many old U.S. homes have single-glazed (one glass layer) windows. These homeowners may choose to add storm windows, or replace them with new double or triple glazed windows having high performance glass to get better energy performing windows and save their energy dollars. While it may take several years for new windows to pay off in energy cost savings, the additional benefits in terms of added comfort, reduced body heat radiation to cold glass, airflow, and improved functionality may make the investment worth it to you. That said other energy improvements - adding insulation, weatherstripping and caulking, air sealing, insulating duct work, and an energy audit - typically reduce energy use and provide better returns for the dollar spent. It is thus very important that you do the basic home weatherization before replacing the existing windows.   Photo of man installing windows Irrespective of whether your new window purchase is to replace the existing leaky ones or for a home being built, here are some considerations which can help you choose energy efficient windows. General Features Windows should have weatherstripping at all moveable joints, be made of strong, durable materials, have interlocking or overlapping joints, and warm-edge spacers between the window glazings. Select new windows with low air leakage ratings. High-performance windows have at least two pieces of glass and a low-e (low emissivity) coating. Low-e storm windows are an energy-saving alternative to replacing windows. National Fenestration Rating Council logo Look for the ENERGY STAR® label and the National Fenestration Rating Council (NFRC) label. For specific window ratings go to the NFRCs Directory Search. The NFRC is an agency that standardizes window testing and ratings. They verify the window performance using computers and lab testing. Manufacturers voluntarily submit their windows for performance tests. Know what the performance measures mean before shopping for windows. Performance Measures U-factor: The U-factor is a measurement of the rate of heat transfer or heat loss through a product. The lower the U-factor, the lower the amount of heat loss, and the better the product is at insulating. U-factors typically range from about 0.20 to 1.20. Look for windows that provide the value for the total window and not just the center of the glass. R-value: The R-value is a measurement of a product’s resistance to heat loss or conductivity - higher R-value materials are more energy efficient with greater resistance to heat flow and higher insulative values. The R-value is the inverse or reciprocal to the U-factor. Solar heat gain coefficient: Low solar heat gain coefficients (SHGCs) reduce solar (sun) heat gain and are a priority in warm and hot climates. The SHGC scale is between 0 and 1. The lower the SHGC, the better the product or window is at blocking unwanted solar heat gain, which is important in hot summers. The SHGC measures the incident solar radiation admitted through a window, both directly transmitted and absorbed and released inward. [...]

Questions and Answers about Caulking and Weatherstripping Your Home


Reviewed and Revised on 10/10/2013    In a well-insulated home, air leaks are the greatest cause of wasted heating and cooling energy. Caulking and weatherstripping are effective ways to rid your home of costly drafts. Questions and Answers about Caulking and Weatherstripping Your Home In a well-insulated home, air leaks are the greatest cause of wasted heating and cooling energy. Caulking and weatherstripping are effective ways to rid your home of costly drafts. Keep in mind that heat always moves toward cold areas. Therefore, in hot, humid climates the biggest concern is hot air coming into air conditioned homes. However, during winter the opposite occurs - heated homes leak warm air to the outdoors through cracks and crevices. How do I check a home for air leaks? When looking for drafts around your windows, check the outside for any sign of caulking that has cracked or peeled. Check inside for leaks safely using a lit incense stick or a simple draft-checker, made with a piece of tissue paper or threads and a metal clothes hanger. On a windy day, move the draft-checker around windows, doors, electrical outlets, ceiling fixtures, attic hatches, and other locations where there is a possible air path to the outside. Air movement around these spots could mean there's an air leak that may need caulking, sealing, or weatherstripping. Infra red imaging can also be used to detect air leakages.  This article by U.S. Department of Energy highlighting 19 spots/areas in a home which are generally leaky could be a good starting point for a homeowner. Where should I caulk and seal? Photo of a person caulking around a window In addition to the window and door areas, you should caulk and seal air leaks where plumbing, ductwork, fans, or where electrical wiring penetrates through exterior walls, floors, and ceilings. This is a lot easier to do in new construction. Also with new construction, reduce exterior wall leaks by caulking or taping the joints if exterior sheathing is used. With new or existing homes, install rubber gaskets behind outlet and switch plates on exterior walls. Inner walls may also need gaskets when the wall cavity is open, or air leaks into the attic from the wall cavity. Use a paintable caulk to seal around the window frames and door frames where the interior frame meets the wall. On the exterior, seal around the window where the frame meets the siding. Do not seal the exterior window weep holes shut, as these allow any water or moisture that does get into the window area to get out. Because caulking is time consuming, use a high quality caulk or sealant suited to the materials and location. Caulks are available for higher temperature areas (e.g. chimneys). Caulks are used when the crack is less than ¼" wide. For cracks wider than ¼", use materials suited for the area or gap such as metal, wood, rope caulk, backer rod, or other materials that will supply a base. Then caulk the area.  When do my doors need weatherstripping? Let’s look at an example. If you have a pair of 6' 8" exterior doors in your home that don’t have weatherstripping, you can easily have an opening of ¼" all along the edge where the doors meet. This ¼" gap adds up to a 20-square-inch opening to the outside. If you saw a hole this big in your wall, wouldn’t you want it fixed? Weatherstripping around exterior doors can be checked with a flashlight. Outside the closed door, move the flashlight slowly around [...]

Why is Home Ventilation a Concern


Reviewed and Revised on 10/15/2013 Reasons for Home Ventilation In days past, energy was cheap and energy efficiency was not a concern. As energy prices increased, homeowners sought to reduce costs by insulating attics, walls, and basements, which reduced large-scale heat transfer and energy loss. Recently, due to high energy costs, better materials, and better information, homeowners and builders are reducing the air leaks to reduce energy loss and and costs. In some homes, the home natural air exchange (replacement of indoor air with outdoor air) may happen every four to 10 hours, compared with every 30 minutes 40 years ago. Although an airtight home saves energy, this reduction of outside air entering the structure can cause problems with indoor air quality. Two of the most common quality issues are excess of humidity and pollutants. Relative Humidity Relative humidity is the ratio of the amount of water vapor in air compared with the maximum amount of water vapor the air may hold at a particular temperature. Dew point is the temperature at which the relative humidity is 100% and condensation forms. Warm air has the capacity to hold more water vapor than cold air. As the air cools, the temperature gets closer to the dew point, or the point where the water vapor begins to settle out of the air in the form of condensation. Roughly, a 20°F drop in temperature cuts the water-holding capacity in half and doubles the relative humidity. Photo: Hygrometers (measure humidity)     In tight homes, human activities such as showers, drying clothes, and cooking raise the relative humidity to problematic levels, leading to condensation on windows and high humidity that may lead to mold growth. The recommended relative humidity for people is around 40-60% for health and comfort. When warm, moist air comes in contact with cool surfaces, moisture condenses on the surface if it is below the dew point. Just as water condenses on a glass of ice water, condensation will form on cold surfaces in a home. This can happen on windows, doors, floors, and even inside walls. Sustained wet conditions may cause structural damage and associated problems with rot and mold. Pollutants Different pollutants exist in different levels in different homes. Examples include carbon monoxide (CO), and other pollutants from combustion appliances and back drafting of chimneys or flues, radon gas from the soil under foundations, formaldehyde and other fumes from building materials, mold spores, dust mites, insect residue, smoke, and particulates. Controlling pollutant sources is the most important strategy for good indoor air quality, but some fresh air ventilation is still needed to dilute what cannot be avoided. Filtration systems are the third and last strategy for good air quality. For additional information see Pollutants in Homes. As mentioned above having a leaky house is not a solution to having ventilation.  Instead, the ideal is to "build tight, and vent right" with controlled, mechanical fresh air ventilation that is ducted in from a planned, clean location and filtered.  More energy can be saved with special equipment such as a heat or energy recovery ventilator to exchange heat between the outgoing and incoming air. ASHRAE has set the standard for minimum ventilation standards in homes. Care must be taken when reducing the natural ventilation in your home, so the indoor air quality[...]

Cary Weiner, Colorado State University Extension




Cary Weiner is Clean Energy Specialist for Colorado State University Extension.  He holds a Master of Public Administration from the University of New Mexico.  His previous experience includes being Renewable Energy Planner for the City of Santa Fe, New Mexico and both a budget analyst and environmental educator for the State of New Mexico.  In his current position with CSU Extension, Cary develops and delivers statewide energy programming to consumers, volunteers, teachers, and agricultural producers.  He has published and peer reviewed numerous fact sheets and decision tools on energy efficiency and renewable energy, presents at workshops and invited events on energy topics for the agricultural community and the general public, and has developed a number of successful programs for teachers, volunteers, and agricultural producers to help them make environmentally and financially sound energy decisions.  

Contact Information

Cary Weiner
Clean Energy Specialist
(970) 491-3784 office
(970) 980-9201 cell

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Connie Neal, University of Missouri Extension



Connie was born in Missouri and raised on a farm in Iowa. She has lived in Missouri for the past 40 years. She earned her bachelor’s degree from Northwest Missouri State University in Family and Consumer Science Education with an emphasis in interior design and a master’s degree from the University of Missouri Kansas City.  She taught at both the high school and college level mostly in the area of housing.  While teaching at the high school level, she combined her housing program with the Building Trades program and they built a turn-key home each year with 5 of those being Universal Design homes.

Connie joined the University of Missouri Extension in 2011.  She has earned a Healthy Homes certification through the National Environmental Health Association.  She has worked with flood victims during the 2011 flood along the Missouri River.  She provides programming on a wide variety of topics including energy, water conservation, weatherization, mold & mildew mitigation, green cleaning, sustainability, H.O.M.E. (Home Ownership Made Easier), Rent Smart and universal design.  She has partnered with other agencies to provide a workshop on universal design for those in the building industry as well as citizens in need of that information.  She was asked by her MU Extension colleague, Housing & Environmental Design Specialist, Marsha Alexander to join her in serving as primary authors for the 2013 Home IDEA Book developed by the Mid-America Regional council (MARC) of Kansas City focusing on communities, homeowners and renters in the Metropolitan Kansas City area.  She also serves 19 counties in the Northwest region.

Contact Information

Connie Neal, M.A., H.H.S.

Housing & Environmental Design Specialist

University of Missouri Extension – Nodaway County



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What is a perm rating?


It is a standard measure of the water vapor permeability of a material. The higher the number, the more readily water vapor (in the gaseous state) can diffuse through the material. A perm rating of less than 0.1 is considered a Class I impermeable vapor retarder (which is also considered a vapor barrier); perm rating between 0.1 and 1 is considered a Class II semi-permeable vapor retarder; a perm rating between 1 and 10 is a Class III permeable vapor retarder; and a perm rating greater than 10 is highly permeable and not considered to be a vapor retarder.. The U. S. Department of Energy's has more information about vapor barriers and vapor retarders .

Questions and Answers about Energy Efficient Home Heating Systems for a Warm Climate


Reviewed and Revised on 10/15/2013 The following terminology can help one understand the energy efficiency of common Home Heating Systems. Annual Fuel Utilization Efficiency (AFUE) The efficiency of a gas (natural or propane) or oil furnace or boiler is measured in terms of its Annual Fuel Utilization Efficiency (AFUE), which describes the heat produced from the energy used. This rating takes into consideration various losses that may be involved such as from pilot lights, heat out of the exhaust stack, start-up, and stopping. AS As an example, a furnace with an AFUE rating of 80 converts 80% of the fuel it burns into usable heat. New furnaces usually rate in the mid 70s to low 80s for non-condensing furnaces and low to mid 90s for condensing furnaces, whereas older furnaces will be in the 50s or 60s. ENERGY STAR ® qualified oil and gas furnaces have annual fuel utilization efficiency (AFUE) ratings of 85% and 90%, or higher, making them up to 15% more efficient than standard models. Keep in mind, however, the AFUE does not consider the unit’s electricity use for fans and blowers. Heating Season Performance Factor The Heating Season Performance Factor (HSPF) applies only to heat pumps. HSPF is the ratio of heat provided in Btu (British thermal unit) per hour to watts of electricity used. This factor considers the losses when the equipment starts up and stops, as well as the energy lost during the defrost cycles. The higher the HSPF, the higher the efficiency of the unit. Typical values for the HSPF are 6.8 for standard efficiency, 7.2 for medium efficiency, and 8 for high efficiency. Variable speed heat pumps have HSPF ratings as high as 9, and geothermal heat pumps have HSPFs over 10. The higher the rating, the more efficient the heat pump. ENERGY STAR qualified heat pumps have a higher seasonal energy efficiency ratio (SEER) and HSPF than standard models, which makes them about 20% more efficient than standard new models. The HSPF averages the performance of heating equipment for a typical winter in the United States, so the actual efficiency will vary in different climates. Coefficient of Performance The Coefficient of Performance (COP) is an older standard used prior to HSPF to measure the efficiency of heating systems. However, the COP is still used to measure the energy efficiency of geothermal heat pumps in the heating mode. By definition, all electric resistance space heaters have a COP rating of 1 (generally considered the most expensive method of heating). A unit with a rating of 3 means that the unit is 3 times more energy efficient than electric resistance heating. Another important question to understand for Home Heating Systems is if  the fuel type being used by the systems can make a difference in the home energy costs? The answer to this is Yes! Homeowners must make it a point to check with their local utility before replacing an existing system. Many utilities have an entire department dedicated to energy conservation and/ or efficiency. They can advise not only on the types of fuel available in your particular location, but also on new technologies that make the most of the fuels available to you. Keep in mind that fuels are measured and sold in different units such as gallons of oil, therms of natural gas, or kilowatt hours (kWh) of electricity, so c[...]

Designing Energy Efficient New Homes for a Warm Climate


Reviewed and Revised on 10/25/2013 Designing for the Climate In warm climate regions such as the Gulf where temperatures are high year round, designing for the climate means designing to reduce heat gain is the first priority. Orientation (direction a home faces) and careful planning of available home space are "free" ways available at the designing stage of new homes which can help to cut energy costs upfront and make a home comfortable and highly functional.   Image of seasonal sun paths Landscaping for energy savings: Even with roof overhangs, a great deal of solar heat gain on the west, east, southwest, and southeast sides of a house can occur from the rising and setting sun. Cooling demand can be greatly reduced by providing shade structures, trees, and shrubs on these sides of a house. Deciduous trees (trees that loose leaves in winter) are preferred to provide shade in the summer and let in the winter sunlight.   Image of an energy-saving landscape plan Pavement reflects and radiates heat that it absorbs from the sun. Avoid unshaded pavement near the house. Small shrubs, ground cover, and non-reflective mulches keep the area around the house cooler and reduce reflected heat. In winter it can be helpful to deflect cold north winds over or around the house with an evergreen barrier. Overall house design: The more surface area the building envelope has the more is the heat gain and loss. As compact the plan is to a square (or circle), the less exposed surface area there is for the same living area. Space-efficient design with open planning can help save energy by reducing the overall size of a house. Open planning saves on room clearance and pathways while making areas appear and feel larger. Kitchens and laundry rooms typically have house heat-producing appliances, so don’t place them on the west side to avoid compounding the afternoon heat buildup. Locating kitchens and living areas for northern or southern exposures can provide a lot of natural daylight without a lot of heat gain. Placing the washer, dryer, and freezer outside of conditioned space can reduce cooling loads even further. Supplement a compact house design with porches, patios, or other planned outdoor areas to extend the living space outside the conditioned space. The ideal is to include a shaded area on the north side for summer use and an area on the south side for winter use. Additional informational about exterior architectural design impacting energy efficiency is available here. Design to minimize solar heat gain: West- and east-facing glass can have nearly five times the solar heat gain of north-facing glass, and more than triple that of south-facing glass. Although the amount of radiant heat at west and east exposures is the same, west is most important to protect, because it occurs during the hottest time of the day. Design to minimize west and east glass and wall surface, and shade it. Try to place most of the home’s glass area within 20 degrees of due south or north.   Image of solar heat gain Orientation of a house for solar control Skylights are not generally recommended, because they receive too much sun and are difficult to shade. Light tubes (domed glass roof fixture[...]

Passive Solar Heating for Homes


Reviewed and Revised on 11/19/2013 A passive solar heating system uses "building components to collect, store, and distribute solar heat gains to reduce the demand for space heating" (NIBS, 2012). It reduces the load on the home heating systems and could even possibly eliminate their need to be installed in the first place, by letting the home to get heated by the natural means.   The amount of passive solar heating possible (sometimes called the passive solar savings fraction) depends on the area of glazing (windows and skylights) and the amount of thermal mass. The glazing area determines how much solar heat can be collected. The amount of thermal mass determines how much of that heat can be stored. The amount of thermal mass and glazing varies by climate. The thermal mass is usually concrete, stone, brick, or other dense masonry materials on the floors and sometimes walls in the home interior. It is important to coordinate the thermal mass with the locations of the sun's rays, so that the sun shines directly on the thermal mass and overhangs, furniture, rugs, and other parts of the exterior and interior are not shading the thermal mass too much. The three major types of passive solar heating systems are: direct gain, trombe wall (indirect gain), and attached sunspace (isolated gain). Direct Gain Direct gain is the simplest and most common passive solar strategy. Sunlight enters the house through south-facing windows. The sunlight then shines on the thermal mass, which absorbs and stores the solar heat. The surfaces of the thermal mass (floors and sometimes walls) are typically a dark color, because dark colors usually absorb more heat than light colors. At night, as the room cools, the heat stored in the thermal mass convects and radiates into the room.   Illustrated example of Direct Gain Passive Solar  Trombe Wall (Indirect Gain) A Trombe Wall (sometimes called indirect gain) passive solar home has the thermal storage in a wall between the south-facing windows and the living spaces. The wall consists of a thick masonry or concrete wall on the south side of a house. A double or triple layer of glass is placed a few inches or less in front of the wall surface. Solar heat is absorbed by the dark-colored outside surface of the wall and stored in the wall's thermal mass, where it radiates into the living space. The Trombe Wall distributes or releases heat into the home over a period of several hours. Solar heat migrates through the wall, reaching the inside surface typically in the afternoon and early evening. When the indoor temperature falls below that of the thermal mass, heat begins to radiate and transfer into the room. In some homes, the Trombe Wall has small openings at the low and high points of the wall. These vents create air movement in the room, as cold air is drawn into the Trombe Wall in the lower vents, then warmed up inside the space between the wall and glazing. The warm air is then released at the openings in the higher part of the wall. This effect creates natural air circulation in the room.   Illustrated example of a Trombe Wall   Attached Sunspace (Isolated Gain) A sunspace, also known as a solar room or solarium, can be built as part of a new home or as [...]

Passive Solar Energy for Homes: Daylighting


Reviewed and revised on 11/15/2013

Natural light can contribute to energy savings inside the home by reducing the need for artificial lighting powered by energy sources. Structures with a long east-west axis and a concentration of windows on the southern exposure receive the maximum benefit from daylight. Windows with low-emissivity (Low-E) glass provide the opportunity for optimum natural lighting while reducing heat gain in the summer and heat loss during the winter months.

Recommendations for the amount of southern windows vary by region. Assuming that the structure is well insulated, non-south windows should be limited to approximately 10-15% of the total window area, providing a balance between energy loss through window openings and effective natural lighting of rooms.

Well placed deciduous trees that loose leaves during the winter can shade southern exposures to reduce summertime heat while allowing natural light to enter the home. Roof overhangs, eaves, and dormers also provide shade while admitting natural light inside. Light colored finishes and building materials allow daylight to bounce off of surfaces and penetrate deeper into rooms.

Design strategies for daylighting include clerestories, monitors, deep well skylights, solar light tubes, and light shelves. Clerestories rise above the roof of the rest of the structure and include windows that admit daylight to the interior. Monitors are similar to clerestories, but include glazing on multiple sides.

Deep well skylights provide an opportunity for incoming daylight to be diffused and reduce heat gain from direct sunlight. The depth of a skylight well is an important part of the overall daylighting strategy of a home.

Solar light tubes are clear or tinted domes coupled with a reflective tube, resulting in diffused natural light that enters the home with little solar heat gain. Light shelves are horizontal structures that extend beyond the surface of the building, shading glazing and evenly distributing light and reducing glare. Light shelves, when properly sized, aid in the deeper penetration of natural light into interior spaces while reducing glare by blocking the occupants’ view of the sky.

When determining the furniture layout of rooms, consider placing items required for tasks in places that allow you to take advantage of natural light. For example, locate reading chairs, desks, or sewing machines near windows where people performing those tasks can most benefit from daylighting.

Passive Solar Design for Homes


 Reviewed and Revised on 11/15/2013 Passive solar design uses the sun’s energy to heat a home in the cold days of the winter, and wind (breezes) to cool a home in the warm days of the summer. You can benefit by incorporating both passive solar heating and cooling in a home design in order to save on energy bills and to reduce the impact of the home on the environment. Passive solar design often doesn’t require the use of mechanical pumps, fans, or electrical devices in order to work. Homes designed for winter sun and summer breezes use the natural movement of heat and air to keep the home comfortable. Many of these design strategies have been in homes for hundreds of years, and the basic principles are easy to understand and can be incorporated into any style or size of home. Passive solar homes are sometimes called climate design homes, because they use the weather and environment to heat and cool the home. In some climate zones, all heating and cooling can be from the sun and wind resources available, while other climate zones will permit a percentage of the total heating or cooling required throughout the year.   Photo of a Passive Solar Home in Missouri Before starting to design and build for passive solar, document the following for the future location of the project: 1. Winter and summer sun altitudes (angles): The winter sun angles help to locate windows and overhangs, so that maximum sunlight enters the house for heating. The summer sun angles help to locate windows, overhangs, and deciduous trees, so the same windows are shaded to avoid heating rooms when cooling is needed. The summer sun angles are much higher from the horizon than the winter angles. 2. Location of prevailing wind breezes in the winter and summer: The winter wind directions help locate wind breaks or wind barriers (e.g. fences) to block these winds. The summer wind directions help locate operable windows to make it easier to use breezes for summer cooling. 3. Average daily temperature and humidity swings (low and high) for each month of the year: Typically, passive solar heating is needed when the indoor temperature drops below 68 degrees, and passive cooling is needed when the indoor temperature rises above 78 degrees. Temperatures between 68 and 78 degrees are generally considered comfortable and require little, if any, heating or cooling. Good resources for local sun, wind, and temperature information: Sun angles: SUN ANGLES Wind directions: WIND DIRECTIONS Average daily temperature: AVERAGE TEMPERATURES Basic Passive Solar Design Principles In order to fully utilize the sun and wind for heating and cooling, these 4 principles should be incorporated into a home: Orientation of apertures (windows) A passive solar home uses south facing windows to let the sun shine in and heat up a thermal mass (see below). These windows should be within 30 degrees of due south and should not be shaded by trees, buildings, or fences, from 9am-3pm on cold days when home heating is needed. In most climates, a passive solar home should be elongated in the east-west axis, so that the south wall is the larger wall area and available for placement of windows. Absorbing thermal mass A the[...]

Passive Solar Cooling for Homes


Reviewed and Revised on 11/19/2013 Passive solar cooling of homes involves combination of several different techniques to help lower cooling costs of the home in an environmentally friendly manner. The techniques used should depend upon the climate of the region. They could range from natural ventilation through breezes and thermal mass to carefully designed and built roof, windows, window overhangs etc. Such homes are easily able to stay cool and comfortable, during the summertime, without much use of an air conditioner. This article primarily discusses ventilation as a passive cooling strategy.  Cross-Ventilation  Cross-ventilation increases the amount of air flow through a room, carrying heat away. As air moves around a building, high pressure areas occur on the windward side, and low pressure areas occur on the leeward side. Good cross-ventilation strategies place air inlets on the windward side and air outlets on the leeward side of the home. Windows, vents, and doors are primary ways to create inlets for windward air, and should be located towards the prevailing wind. If this is not possible, landscaping and “wing” walls can redirect incoming air flow toward the inlets. The best way to incorporate natural cooling is to place operable (openable) windows or vents on two sides of a room to pull air throughout and allow warm air to exit. While open windows directly opposite one another allow for the most air flow, opening windows on any two walls will help air move through the room. Open doors to all rooms to allow air to move throughout the house. Areas allowing inward air flow should be approximately one-half to equal in size to areas where warm air exits the home.   Illustrated example of cross ventilation Stack Ventilation Stack ventilation takes advantage of the natural tendency of hot air to rise above cold air in a room or a house. A common home example of stack ventilation is a chimney, where cold air is drawn into the fireplace, and warm air rises through the flue and exits the home at the roof. Properly designed stack ventilation pulls air from the exterior through a strategically placed opening (typically a window or vent), on the low side of a wall. Cool air is pulled throughout the home while warmer air rises above the cool air to exit through an opening near the top of the structure. The warm air exits the house through a high window, skylight, dormer, or vent placed high on a wall. Installing overhangs or plantings that shade and protect windows and doors can cool the air being pulled in from the outdoors. This results in even more comfort when using stack ventilation strategies. Areas allowing inward air flow should be approximately one-half to equal in size to areas where warm air exits the home.   Illustrated example of stack ventilation   Ceiling fans can assist with both cross and stack ventilation. Consult the manufacturer about reverse switches that allow the fan to push heated air down during the winter months and pull cool air up during the cooling season. Passive cooling strategies can sometimes add humidity to the indoor air, which may not be [...]

Geothermal Heat Pumps


Photo taken during the installation of a ground source heat pump. Introduction A heat pump can be an efficient alternative to the standard home heating system. Moreover, during the cooling season, its function can be reversed as it acts as an air conditioner. Heating and cooling buildings using ground source heat pumps (also known as geothermal heat pumps) is becoming more popular. The Basics To understand how a heat pump works, think for a moment about a refrigerator. This appliance extracts heat from the interior, cools it down, and dumps the extracted heat to the area around the refrigerator. The mechanical device that performs this function is a heat pump, although refrigerators do not have the ‘reverse’ function that is available for home heating and cooling. Heat pumps heat or cool a building basically by moving heat from one location to another. In the winter, they move heat from the air, ground, or a water source into a building where it is concentrated to provide heating. In the summer, the process can be reversed and the heat from a building is removed, cooling the building. For purposes of this article the information will concentrate mainly on the heating aspects of ground source heat pumps. There are two types of heat pumps: air source and ground source. An air source heat pump typically extracts heat from the air, concentrates it (even when that air is cool) and transfers it to the indoors or outdoors depending on the season. These units are better suited to mild climates for heating, since their capacity is limited. A ground source heat pump extracts heat from the earth or a body of water, and the home is heated from this source. These units are often equipped with a desuperheater, which utilizes excess heat to produce domestic hot water. In all heat pumps, a water antifreeze mixture is used as the transfer medium between the heat source (the ground) and the heat pump. The heat pump then concentrates the heat and disperses it into the home. Household air is never in direct contact with the heat source (air, soil, or water). Ground source heat pumps generally require three main components: the heat exchanger(ground loop), a heat pump, and a distribution system such as air ducts or in-floor tubing. The heat exchanger, or loop, is simply a length of tubing placed underground and used to transfer the heat from one location to another. The heat pump moves water through the loop and passes it through a condensing unit which utilizes refrigerant to concentrate the heat. In the winter, that heat is then released through the buildings air ducting systems or in-floor hot water (hydronic) heating system. The process can be reversed for cooling in a home. Other names Geothermal energy and ground source heat pumps are often confusing terms. Geothermal simply means "earth heat" (geo- earth, thermal– heat), so geothermal energy is energy produced from an Earth-based heat source. Ground source heat pumps do not create energy, but simply move heat energy from one location to another. Even though many in the scientific community consider it technically incorrect to use t[...]

Tips to Maintaining Energy Efficient Home Electrical Systems


Reviewed and Revised on 01/03/2014 Photo of a home electric meter Electricity is uniquely unforgiving—even the smallest mistake can cause fire, injury, or death. This article is an introduction to your home’s electrical system, but is by no means inclusive. Contact a licensed electrical contractor for more information about your home’s specific electrical system and what changes, if any, should be made. Common terms An amp, short for ampere, measures the amount of electricity moving through a wire. Amps give electricity its "shock." A volt is the “pressure” that pushes electricity through wires. This is how electricity gets from the power plant to your house. The amount of power a device consumes is termed watts, or wattage. Wattage in most cases is determined by multiplying the amperage by the voltage. Electrical use is measured in kilowatt-hours (kWh)—wattage multiplied by time, divided by 1000. Electrical current is carried in wire from the point of generation to the point of use. Wire is sized according to the amperage it is designed to carry; codes specify the maximum current carrying capacity that is safe for wires of different diameters. Tips 1. When the price of copper soared in the early 1960s, manufacturers responded by making residential electrical wires out of aluminum. Between 1962 and 1972, nearly 2 million homes were wired with aluminum, and many of these have not been upgraded. Consult a licensed electrical contractor if your home was built during this time period, or if you think you have aluminum wiring, as corrosion can lead to fire hazards. 2. Receptacles (also known as outlets) supply power to electrical equipment used in houses. Up until the mid-1960s, ungrounded receptacles were installed in most homes, but grounded receptacles are now the rule. Grounding ensures that if a short circuit occurs, electrical current flows through the ground system and trips a breaker or blows a fuse. A grounded outlet has three holes for each plug; the rounded slot is the ground connection. Make sure all receptacles in your home have 3 holes, if not get them changed to a 3 hole one. 3. Look at your home’s service panel—a fuse box or circuit panel, usually located in a metal box. This panel serves two functions—as a master switch for turning off all of the power in the house, and to direct utility-supplied electrical power into branch circuits to safely distribute power throughout the house. Each fuse or switch controls the electricity flowing through a specific area of the home and serves to cut off the power when a circuit is overloaded. Without adequate protection, overloaded wires heat up, which can lead to a fire. It is a good idea to “map” your service panel. That is, label each fuse or switch with the room or area it serves. The National Electrical Code (NEC) lists the specific fuse/breaker size and the wire gauge that it is meant to protect. When a fuse blows or a breaker trips, it means there is something wrong. The problem could be from outside of your home (e.g. a power surge during a l[...]

Using Greywater for Home Gardening


Reviewed and Revised on 10/17/2013

What is greywater and how can it be used?

Greywater is the domestic wastewater from all sources except the toilets. As per the EPA wastewater sources can include water from:

  • laundry

  • shower/bath

  • washing machines

  • dishwasher

  • kitchen sinks

Greywater can be used for home gardening and landscape irrigation. This can have two major benefits.

  • It reduces the need for fresh water and hence is a great way to conserve water as well as energy. Large amounts of energy are used in intake, treatment and transportation of water to residential homes. All that energy gets conserved. 

  • Reuse of waste water which otherwise would have entered first the sewers and then the waste water treatment plants reduces the amount of water entering into these streams. This again prevents the energy, which would have otherwise been used in treatment, to be used and hence gets conserved.

Greywater should not be confused with Blackwater. The term Blackwater indicates wastewater from the toilets. 

Greywater does not need extensive treatment before reuse. It however needs to be used carefully as it contains contaminants such as grease, hair, detergents etc. and hence may not be suitable for all garden uses.Also, all greywater must be used within 24 hrs of its production. To utilize greywater in a household the home plumbing must have separate drains for blackwater and greywater sources, which is easier to do in new constructions than the existing ones. There are however a number of ways it can be achieved in the older homes.

In most states, the Department of Health regulates the installation and reuse of greywater and onsite systems. Details may also be found in your Building Code. It is also recommended to consult your local water authority or council for advice on greywater use regulations.

Additional information on greywater can be found here.

No to Low Cost Actions to Save Home Energy and Money


Reviewed and Revised 01/03/2014 Simple tips designed to help you save energy in your home with little or no out-of-pocket costs. Heating Set thermostats no higher than 68 ºF when people are home.  Lower the thermostat when you sleep or not at home. Lowering the thermostat by 10 to 15 degrees for 8 hrs can help you save  5-15% annually on your heating bill. website states that if the setback period is 8 hrs or longer than savings of as much as 1% for every degree setback can be achieved.  To ensure the heat gets to where it is supposed to go, use mastic or foil-faced tape to seal the seams and any cracks in air handling ducts. Have the heating system serviced each year to ensure efficient operation. Clean or replace furnace filters. Dirty filters reduce the efficiency of the furnace or heating system and waste valuable fuel. Clean or replace the filter(s) as directed by the manufacturer. Do not place furniture and curtains over or around the heat registers or in front of cold air returns. These items will block the airflow. Put on a sweater or warmer clothing for comfort, and lower the thermostat even more. Layer clothing. Closed or tighter cuffs and collars help to retain body heat. Never use the stove for additional heat. It is dangerous. Besides causing a fire hazard, fumes given off by combustion from gas appliances can result in increased carbon monoxide levels. On sunny days, open blinds, shades, and curtains, especially if your windows face south. At night, close the blinds, shades, and curtains to help keep heat in your home. Cooling During the day, keep window shades or blinds down and closed, especially on east and west facing windows. In the evening and early morning, open windows if the temperature and humidity are lower. The recommended thermostat setting for air conditioning is 78 ºF when people are at home. This setting should be turned up to higher temperatures when no one is home to help reduce the energy use. If you have a window air conditioner, place it in a window that is shaded or on the north side. This will help it perform more efficiently. Weatherstrip around the air conditioner. When the cooling system is operating, close and lock all windows and doors. Close exterior sliding storm windows. Locking doors and windows creates at tighter seal and reduces air leaks. During less humid warm days, open the windows in the mornings and evening to allow fresh air to help cool the home. Correctly positioned shade trees and awnings reduce the heat gain in the home during the warm and hot days. Use towels or a draft stopper to block air coming in under doors that lead to the outdoors, or buy a door sweep. If the door leaks around the entire frame, install foam weatherstripping between the door and the frame. Use blinds, shades, and lined curtains or draperies to block heat gain during the summer. If your curtains or draperies aren’t lined, use a sheet, or purchase[...]

Understanding Dissimilarities in Different Kinds of Homes: Mobile, Manufactured, Modular, and Factory-built, for Home Energy Efficiency


Reviewed and Revised on 01/03/2014 All kinds of homes- mobile, manufactured, modular, and factory-built, are built in a factory. The difference lies in how much construction occurs at the factory and how much assembly occurs at the actual home site. When more work is done at the factory, less labor and work is needed at the home location. Energy efficiency issues and solutions for all these homes could be similar or vary depending upon the construction process and other issues. This article is meant to provide the readers with an overview about the basic differences in the different kinds of homes to help them in turn understand the energy issues in their particular home type.  Mobile and Manufactured Homes Photo of Mobile home The term “mobile home” refers to factory built homes built prior to the establishment of HUD code in 1976. Mobile homes are now known as manufactured home and are federally regulated by this HUD Code, which provides design and construction requirements for the complete production of the home in a factory plus the permitted modifications for its on-site completion. The HUD code supersedes all state and local codes in the country and is the "only" federally regulated code applicable on national level.  Manufactured HUD code homes are built entirely at a factory, have a chassis for transporting, and usually require only hook-up of utilities, anchoring, and certain appliances upon delivery. New technology has made available high ceilings and steep roof pitches through hinged roof systems and two-story homes, so they may look like site built homes. These homes may be installed on a temporary or a permanent foundation. When installed, a mobile home’s wheels and axles could be removed, but the chassis must stay in place. article by Department of Energy provides information on energy related issues for manufactured homes. Modular Homes Photo of Modular home A modular home is one that is built in sections (modules) at a factory and then assembled on site. It may consist of fully factory finished modules that need only a site built foundation and finishing of the seams where modules connect. Sometimes, the modules are not completely factory finished and may require finishing work (e.g. carpet, paint, appliances) at the home site. Modules may be stacked to form multiple stories.  A modular home must be designed, permitted, built, and inspected in accordance with the local building codes for the site where it is installed. It must also have a permanent foundation designed and built specifically for that home. Factory-built homes “Factory-built” is a broad term that includes manufactured HUD code homes, modular homes, and homes assembled with factory-built segments. Panelized and precut homes may be considered “site built,” but are distinguished from “stick built” homes that are framed on site with ind[...]

Mike Vogel, Montana State University Extension Service





Mike is Professor and Housing and Environmental Health Specialist with Montana State University (MSU) Extension Service since 1982. Since 1997, Mike has also served as MSU Extension Family & Consumer Sciences Program Leader.

Mike’s primary responsibility is directing and developing housing education programs and resources for Montana consumers and tribes.  Since 1977, he has been involved with energy-efficient construction and training with the U. S. Department of Energy.  In 1977 he authored one of the first consumer-targeted books dealing with home energy conservation - The Home Energy Primer.  While at West Virginia University (1977-1982), Mike conducted extensive research on the feasibility of passive solar applications for existing homes and developed a passive solar retrofit decision-making model for selecting solar suitability of an existing home site.  To demonstrate energy-efficiency, solar applications and alternative building systems for home retrofit applications, Mike served as Center Director of the WVUTechnology Education Research and Demonstration House from 1980-1982. 

While at Montana State University, Mike has contributed to six books, produced dozens of technical training manuals, research/technical reports, and consumer oriented bulletins and fact sheets dealing with housing and environmental health. Much of Mike’s work has focused on the development of nationally used environmental health training programs. 

In 1992 Mike established the Montana Weatherization Training Center at MSU.  In partnership with the Montana Weatherization Assistance Program, the Center provides comprehensive, hands-on training, technical assistance and certification to contractors dealing with all aspects of weatherization and health and safety.  A unique focus of the Center has been the production of the national weatherization training video series, WxTV –   Mike was an initiating partner and co-led for the eXtension Home Energy Community of Practice initiative providing the leadership for content dealing with improving the energy-efficiency of existing homes.

Contact Information

Michael P. “Mike” Vogel, Ph.D.
Professor, Montana State University Extension
102 Taylor Hall, Bozeman, Montana 59717
(406) 994-3451

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Home Energy Efficiency

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Sarah Kirby



Dr. Sarah Kirby is an Associate Professor, Housing Specialist, and Department Extension Leader in the Department of 4-H Youth Development and Family and Consumer Sciences at North Carolina State University. Dr. Kirby directs the E-Conservation Residential Consumer Energy Education and provides leadership for the national eXtension Home Energy Community of Practice. She is a member of the Home Energy eXtension Community of Practice and the Family Caregiving Community of Practice. Dr. Kirby serves as the North Carolina Cooperative Extension state coordinator for the Healthy Homes Program focused on improving the health and safety of children in homes by reducing housing hazards that cause injury and disease.

Contact Information

Sarah Kirby


Meet all of our home energy experts

Milton Geiger, University of Wyoming Extension


Milton currently serves as the energy extension coordinator for the University of Wyoming Extension and School of Energy Resources. In this role, he works with renewable energy (large and small-scale), energy efficiency, conservation, and the community impacts of fossil fuel development.  Before joining UW Extension, Milton worked for USDA Rural Development-Wyoming, serving as the rural energy coordinator, where he administered the Rural Energy for the America Program (REAP). 

Milton is a graduate of Colgate University (B.A. Environmental Economics) and the University of Wyoming (M.S. Agricultural/Applied Economics and Environment/Natural Resources).  Previously, Milton held certification as an International Ground Source Heat Pump Installer. Currently, he is certified by the Green Building Certification Institute as a Leadership in Energy and Environmental (LEED) Green Associate. Additionally, he holds certification from the Association of Energy Engineers (AEE), as both a Renewable Energy Professional (REP) and a Certified RETScreen User (CRU).

Contact Information:

Milton Geiger, Energy Extension Coordinator

University of Wyoming Extension/School of Energy Resources

Laramie, WY 82071


Ph: (307) 766-3002


Questions and Answers about Home Insulation


Reviewed and Revised on 11/13/2013    Photo of Batt insulation Properly insulating your home will not only help reduce your heating and cooling costs, but also make your home more comfortable. How does insulation reduce heat transfer? Insulation is rated in terms of thermal resistance, called R-value, which indicates the resistance to heat flow per square foot of cross-sectional area perpendicular to the direction of heat transfer. Heat transfer is accomplished by conduction, convection, and radiation. Conduction is the transfer of heat from molecule to molecule, such as in a solid. Convection is the transfer of heat by the movement of a fluid. Radiation heat transfer is the transfer of heat by electromagnetic energy such as light. R-value, as listed for most building materials, is a measure of the resistance to heat transfer by conduction. It is measured in such a way as to reduce or eliminate heat transfer by convection and radiation. If the insulation is an opaque solid, conduction is the only mode of heat transfer. Much fiber glass insulation is of open construction in which some heat transfer by convection or radiation is possible. Convective transfer within the insulation is helped by long vertical installations, by heating from below or on one side, and by large temperature differences—a knee-wall between a conditioned room and an attic combines all of these. Radiation heat transfer within the insulation occurs when the radiative energy travels in a direct line-of-sight path through the air spaces, or is reflected by the glass fibers through the air space. The magnitude of the radiation transfer is highly dependent on the temperature of the source of radiation. Radiation and convection within the insulation can reduce its expected resistance to heat transfer. If the radiative or convective heat transfer within the insulation is reduced, the insulation’s resistance to heat transfer increases. For example, you may have heard that foam sheets applied to a wall assembly increase the effectiveness of the fiber glass insulation in the wall cavity as well as providing insulation on its own. This is because the foam insulation reduces the convective and radiative heat transfer within the fiber glass insulation. Insulations, such as radiant barriers, may be advertised as having an effective or equivalent R-value. This means that for the particular situation that the equivalent R-value was determined, the insulation is as effective as a comparative insulation–usually unfaced fiber glass—in reducing the heat transfer. It does not mean that it will produce the same results as insulations with the same rated R-value in installations other than that for which it was compared. R-value measurement standard assumes no air leakage through the insulation. Air currents in standard density fibrous batts and loo[...]

How the Exterior Architectural Features of a Home, Built in a Warm Climate, Affect its Energy Efficiency


Reviewed and Revised on 11/13/2013 The shape and exterior structure of a home play major roles in determining its energy efficiency. Building elements included in the shape are - height, width, and depth. These are also called building footprint. The exterior structure, which is also called building envelope, comprises of the walls, roof, windows, doors, and cladding. The footprint and envelope of a home can either enhance its energy efficiency or cause higher energy consumption. Homes having simple or uncomplicated shapes are typically more efficient to heat and cool than the homes with complex or irregular shapes. There are a few important things to understanding how shape of a home affects its energy efficiency. Firstly, heat gets transferred through a building envelope at different rates depending upon the efficiency of the materials used. Heat moves only when there is a difference in temperature between two objects that are in contact, and it always moves from the warmer to the cooler object. Heat continues to “flow” until all touching materials of the building envelope reach the same temperature. To be comfortable inside a home, we usually want the inside to be at a different temperature than the outside. Depending upon the climate, the shape of the home and the materials used in the building envelope are important determinants of energy required to heat or cool the house and for residents to feel comfortable. In hot and humid climates, the shape of a home should be such that it has minimum solar heat gain, thus requiring minimal energy to cool the house to comfortable temperatures. Compactness of a home Compact homes, when properly designed, are more energy efficient than irregularly-shaped homes. They gain less heat in the summer and lose less heat in the winter since a smaller surface area means less exposure to the outside elements of sun, rain, and wind. Also, compact homes use fewer building materials, and simplify the length and complexity of mechanical duct runs and plumbing pipes. As a simple example, the figures below show 2 designs that have approximately equal floor areas (2062 square feet and 2095 square feet respectively), yet significantly different wall areas (1817 square feet vs. 2639 square feet, assuming exterior walls are 10 feet). There is over 45% more wall area in the 2nd irregularly shaped home. The 1st compact design home has less surface area exposed to the outside, thus allowing less heat gain in the summer and less heat loss in the winter. Two story homes are generally more efficient than one story homes, because of the reduced footprint and roof area, and because the summer sun is higher in the sky and a smaller area of the wall gets exposed to the direct sun. Siting and Orientation of the home Along with building shape and envelop[...]

Importance of Air Tight Construction in Providing a Continuous Air Barrier in New Homes


Reviewed and Revised on 11/13/2013   Construction gaps and resulting air leakages can increase heating and cooling costs, create comfort and moisture problems, draw in pollutants, reduce fire safety, and serve as an entry for rodents and insects. Windows, doors, and outside walls can contribute to air leakage, but the greatest losses occur in gaps and holes that are hidden from view and cause a continuous air exchange between the interior and the attic, crawl space, and outdoors. Homes should have a continuous air barrier system that surrounds all conditioned space — a combination of materials linked and sealed together to create an air tight building envelope with little air leakage. In a warm climate, an exterior air barrier (outside the insulation) is preferred. In a cold climate, having both interior and exterior air barriers is advantageous. Note: It is important to distinguish between an air barrier and a vapor barrier. They are not the same things. Consistent and stringent quality control during construction helps to create and preserve a continuous air barrier in any newly constructed home.In fact, all new ENERGY STAR® qualified homes must follow a Thermal Bypass Checklist. Air sealing is always the most important first step to achieving air tight construction and high energy efficiency. Insulation is the next step, which is able to perform at its rated level only when the home construction is air tight. Common areas often neglected in a home for air sealing  1. Bypasses: There are several hidden areas in a home that bypass the building envelope to create major pathways for unwanted air exchange with the attic, crawl space, or other unconditioned areas. Common neglected bypasses include soffit (underside area of a structure) areas of kitchen cabinets, the return air plenum (path from the air filter to the air handler unit), the area around a fireplace chimney, plumbing stacks, unfinished areas behind tubs and showers, dropped ceilings, chases for duct work, exhaust vents with no dampers, and even insulation. Illustration of sealed bypasses and penetrations 2. Penetrations: Holes in the building envelope and air barrier system commonly left unsealed include holes for plumbing, electrical boxes, exhaust fan housings, air registers, attic access doors, and wiring. Airtight electrical boxes with gaskets are available; regular boxes should have wiring holes caulked and should be sealed to the drywall. Illustration of an airtight electrical box 3. Recessed light fixtures: Standard recessed lights put a leaky, un insulated hole in the worst place of all - the insulated attic floor. It’s best to avoid them altogether, and choose surface-mounted fixtures. If recessed lights are used, specify “airtight” models rated[...]

Considerations for Selecting Energy Efficient Windows for Homes in Different Climates


Reviewed and Revised on 11/13/2013 It is very important that you consider your climate when selecting energy efficient windows to reduce home energy use. One size or type does not fit all homes and climate zones. Window energy efficiency criteria for different climates In temperate climates with both heating and cooling seasons, select windows with both a low solar heat gain coefficient (SHGC) and a low U-factor to maximize energy benefits and savings. For cold or very cold climates where home heating is the major energy use the focus should be on finding a window with a low U-factor. U-factors of 0.35 are recommended and often required in building codes, but U-factors may be as low as 0.15. In addition, select windows with spectrally selective coatings to reduce heat gain and windows that are gas filled with low emissivity (low-e) coatings on the glass to reduce heat loss. According to the U.S. Department of Energy (DOE), moderate solar gain low-e coatings of 40 to 55 typically are selected for northern and mixed climates where winters are cold and summers moderately hot. In cold climates, the low-e coatings are applied in the window space to the glass surface facing the living area. Obtain information on specific window characteristics recommended for your climate zone when selecting windows for efficiency. For south-facing windows, US DOE suggests a solar heat gain coefficient (SHGC) of 0.60 or higher to maximize solar heat gain during the winter. East and west facing windows should have a lower SHGC and be shaded. In cooling-dominated or warm to hot climates, look for a low SHGC at or below 40%. Buy products with low SHGCs to reduce unwanted heat gain. The U.S. DOE recommends windows with low-e coatings on the glass to reflect some of the sunlight, keeping your rooms cooler. Windows with low-e coatings, especially spectrally selective coatings, reduce summer heat gain and air conditioning costs without reducing visible light. For hot climates, the low-e coating is applied to the interior of the outside glass (glass facing outdoors) and are used especially on east and west facing windows and unshaded south facing windows. Apply sun-control or other reflective films on south-facing windows to reduce solar gain when there are no extended awnings or exterior shading. Select quality energy efficient windows in any climate Windows should have weatherstripping at all movable joints, be made of strong, durable materials, have interlocking or overlapping joints and warm-edge spacers between the window glazing. Low-e storm windows save even more energy. Select windows with air leakage ratings of 0.3 cubic feet per minute or less. Look for the ENERGY STAR® label and the National Fenestration Rating Council’s label to h[...]

Proper Installation of Home Insulation for Energy Efficiency


Reviewed and Revised on 11/12/2013   Proper Installation of Home Insulation is very critical to ensure that the desired Home Energy Efficiency gets achieved. Installation: Compressing (squeezing) of insulation erodes its R-value and should be always avoided. Batt and roll insulation should be slit and trimmed to fit around wiring, electrical boxes, etc. If using paper-faced batts, staple the paper on the ends, not inside, the studs. Insulation should be trimmed to fit into voids around rough openings, chimneys, etc. Even a 2% gap makes a difference in the rating of a home, and the compression of insulation can make it almost useless. In climate zones 1 and 2 (hot, humid), un faced friction-fit batts are recommended. Continuous coverage to reduce thermal bridging: Non-insulation materials, even wood framing, create a thermal bridge that allows greater heat flow through the wall. Materials that are good conductors of heat (e.g. metal framing) can substantially erode the effectiveness of insulation. Building systems that reduce thermal bridging, provide a continuous “thermal blanket” surrounding the conditioned space and therefore preserve a higher “whole wall R-value” include: using insulating foam sheathing in addition to wall cavity insulation, OVE (24 inches on center), SIPS and ISPS (foam core panels), ICF (foam forms and concrete) and AAC (insulating concrete). Image of a raised top plate       Attic insulation should extend over the top of exterior walls without blocking air flow from the soffit vents. This can be done with a raised top plate or raised heel truss to increase the roof height at the eave. In hurricane zones, check to make sure this raised top plate assembly is wind code compliant.   Exterior walls with headers over door and window openings should be framed to include insulation in the headers; double header lumber can be placed on the exterior side to leave space for rigid insulation on the interior side. Various methods have been developed to provide continuous insulation in exterior wall corners and at T-walls (where an interior wall intersects an exterior wall), which are normally blocked by framing lumber. [...]

Tips For Mechanical Air Filters to Improve Home Energy Efficiency


Reviewed and Revised on 10/30/2013 Images of air filters (Left-clean; Right- dirty).  Studies have shown that dirty filters on the return air grille of your heating and cooling systems greatly reduce the efficiency of your system, wasting energy as well your money. Dirty filters can also reduce living comfort by restricting air circulation and not capturing dust particles, allergens and pollutants in the indoor air. Your equipment may have to work harder and its life can get shortened. It is thus important to change dirty air filters before they begin to create problems. This articles discusses only the mechanical air filters, electronic air filters are also available in the market for removing pollutants from indoor air. Since, filters need frequent inspection and cleaning/change it is best to have a monthly preventive maintenance program, say on the 1st of every month. Inspect the filters on the prescheduled day. If dirty replace them. You may also choose to follow manufacture recommended schedule for replacement.  Normal recommendation is to change the filters once every 3 months. A more frequent change may be in order if furry pets, smoke,and/ or dusty conditions exist in the home. MERV (minimum efficiency reporting value) is a standardized rating system for filter efficiency, developed by ASHRAE. MERV values range from 1-20. Higher the MERV, higher is the filter efficacy in capturing and holding smallest sized dust and pollutant particles. Different kind of filters are available in the market today. The disposable ones are pleated and non-pleated. The flat non pleated disposable filters have a MERV of 1-4. They can protect the HVAC equipment from dirt buildup on fan motors and coils, but are not considered good for indoor air quality. Because of low MERV value, these have low efficiency on small airborne particles, and medium efficiency on larger particles, as long as these particles remain airborne and can pass through the filter. Several small particles found within a house include viruses, bacteria, some mold spores, a significant fraction of cat and dog allergens, and a small portion of dust mite allergens. It is important all of these get removed from the indoor air of a home to ensure healthy indoor living environments for the occupants as well as pets, if any. It is thus important to pay attention to MERV rating when buying air filters. Image of a pleated air filter Pleated filters have more surface area, and can capture more particles with less restriction to airflow. They are recommended over basic, flat filters, and are available in a range of filtration efficiencies. Medium efficiency filters with a MERV of 5-13 [...]