Reducing Energy Use
When we conserve energy resources, our nation can enjoy cleaner air and a healthier environment, and we can help protect the climate by reducing green house gases. In 2008, Americans saved more than $19 billion and avoided greenhouse gas emissions equivalent to those of 29 million cars through choices they made with energy-saving measures and energy-efficient homes.
Homeowners can save energy while improving their home's comfort level by adopting energy-efficient building practices. Substantial savings are possible whether building a new home, renovating an existing one, or simply updating some features to improve your home's efficiency. At the same time, homeowners can use green power for their home to reduce further their consumption of energy from fossil fuels and lower their carbon footprint. Energy efficiency and green power are two ways to go green in your home.
- Introduction to Energy Saving at Home
- New Home Construction
- Advanced New Home Construction
- Green Power for the Home
You can save energy while improving your home's comfort and helping the environment by making your home more energy-efficient. In fact, making your home energy efficient is the first step to green. And indeed, energy efficiency will save you money, allowing you to invest in other green technologies to make your home more healthy, comfortable and sustainable.
For basic recommendations, strategies and tips for energy efficiency improvements and products for your home, EPA developed the ENERGY STAR program. ENERGY STAR is the government backed symbol for energy efficiency. An ENERGY STAR labeled product, appliance or building indicates superior energy performance. The ENERGY STAR Program is a great place to begin whether making improvements to an existing home or building a new home. Learn more at http://www.energystar.gov to understand your home and the steps necessary to improve its energy efficiency.
Where to Start
EPA has a wide variety of information, on-line tools and calculators to help homeowners get started on
evaluating energy use in their home and finding cost effective ways to solve problems and make their home
more energy efficient. An assessment of your home may be the best place to start.
Compare your home's energy use to similar sized homes and climates across the country with the Home Energy
Yardstick (home utility bills needed) to see how you measure up with your neighbors.
Find the recommended home improvements to make your home more energy efficient based on the climate where you
live by answering a few questions about your home using the Home Energy Advisor.
Get practical pointers and tips on making a home more energy-efficient using the ENERGY STAR @ Home Tool.
This tool presents energy saving tips to operating your home more efficiently
- If you feel that you need a professional, you can earn about home energy audits to find out how to make your home more energy efficient.
Ways to Improve the Energy Efficiency of Your Home
While a tailored audit for your home will provide specific recommendations to improve your home, there are key
areas of the home that are common trouble spots and frequently contribute to a home's poor energy performance.
These areas and the ENERGY STAR resources that can help you address these issues include:
Seal and Insulate
Your home's envelope - the outer walls, ceilings, windows, doors and floors - may be letting too much air into or out of the home. Hidden gaps and cracks in a home can create as much airflow as an open window, and can cause your heating and cooling systems to work harder. Sealing coupled with insulating your home's shell is often the most cost effective way to improve energy efficiency and comfort. Download the Do-it-yourself Guide to Sealing and Insulating with ENERGY STAR to better understand the importance of air sealing and insulating and key steps to sealing and insulating your home.
Windows can also account for a significant percentage of your heating bill in the winter, as cold air can infiltrate into the home through leaky windows and warm air escapes, making your heating system run more. And during the summer, your air conditioner must work harder to cool hot air from sunny windows. If you are replacing or installing windows, doors or skylights, you can reduce energy costs by installing energy-efficient windows, doors, and skylights in your home. Look for ENERGY STAR Windows, Doors, and Skylights
Heat and Cool Efficiently
Annual maintenance is a must for a well performing heating and cooling system. Clean your filter regularly and schedule annual maintenance by a qualified contractor. Learn how to properly install and use a programmable thermostat to save energy.
In houses with forced-air heating and cooling systems, ducts distribute conditioned air throughout the house. In a typical house, however, about 20 percent of the air that moves through the duct system is lost due to leaks and poorly sealed connections. The result is higher utility bills and difficulty keeping the house comfortable, no matter how the thermostat is set. Sealing those leaks in the ducts is a must to get better performance from your heating and cooling system. In addition, insulating ducts in unconditioned spaces that get especially hot in summer or cold in winter (such as attics, garages, or crawlspaces) can save significant energy. For more detailed information about the importance of sealing the leaks from your ducts go to http://www.energystar.gov/index.cfm?c=home_improvement.hm_improvement_ducts
If you are looking for new heating or cooling equipment, look for equipment labeled ENERGY STAR. Replacing your old heating and cooling equipment with new, energy-efficient models is a great start. But to make sure that you get the best performance, the new equipment must be properly installed. In fact, improper installation can reduce system efficiency by up to 30 percent - costing you more on your utility bills and possibly shortening the equipment's life. For specific steps to heat and cool efficiently, follow this link to ENERGY STAR's heat and cool efficiently page and download the Guide to Energy Efficient Heating and Cooling.
Ground Source Heat Pumps
The Earth's heat, called geothermal energy, constantly flows outward from its core and can provide a useful supplement for heating and cooling. Unfortunately, many people think you have to live over a hotspring, a geyser or some other intense source of geothermal heat to be able to make use of this source, but this is far from the truth.
You can use geothermal energy-no matter where you live in the United States-to heat and cool your home by using a ground-source heat pump
For more information on the potential for geothermal heating/cooling in your home, go to:
Heat/Cool Portions of Your Home
Heating and cooling only those portions of your house that you use, is one way to heat and cool more efficiently. This can reduce fuel consumption, conserve energy and save you dollars while maintaining comfort. However, in using this strategy there can be potential negative side effects that must be avoided. If there are areas of your house you don't need to use often, you can close vents and air registers to them and direct the heating or cooling to the portions of the home where you spend most of your time. Homes with central heating and cooling can benefit the most from this technique. For example, during the winter consider directing more of the heat to the family or living room if that is where you spend most of your time. If rooms are not used, you can close air registers and doors and confine heated or cooled air to the areas where you need it most. Note in winter, that the cooler parts of your home will still need to be heated to above freezing to avoid freezing pipes. Also, with some HVAC systems, especially those that are already high- performance, efficient systems, closing too many vents or registers may imbalance the entire heating and cooling system and actually make the system run less efficiently. In addition, moisture problems need to be avoided where certain rooms or areas of a house are not getting dehumidified air.
Fresh Air Cooling Strategies
Providing fresh air flow into a house is a low-cost and potentially energy-efficient way to cool a home and maintain good indoor air quality. In good weather, natural ventilation (when air moves through windows or doors) can suffice for cooling. On some days, the air temperature at night is pleasantly cool and letting this air into the house during the night can significantly cool down a house after a warm day. However, there will be times when it is too hot or humid, or pollen levels are very high, and this will not be effective -- or may even be undesirable -- and air conditioning may be necessary. In addition, it is important to make sure windows are closed when they need to be, such as in storms and blowing rain, and if air conditioning is finally used, that the house is closed up tightly for maximum efficiency. It makes no sense to air condition (or heat) a house with a window open! Given this, fresh air cooling takes some attention and diligence to do it right. Natural fresh air ventilation can also be supplemented by a number of low-energy mechanical ventilation devices that can help. These include:
- Ceiling fans are a useful alternative to help keep you cool while reducing or eliminating the need to use air
conditioning. Typically a ceiling fan consumes much less electricity than does a central air
conditioner. A ceiling fan doesn't cool or de-humidify a room - it only cools you through a
wind-chill effect against your skin. Ceiling fans are also inexpensive to purchase. Make sure,
however, to turn your fan off when you leave the room. If you are not there to feel the cooling
air movement on your skin, continuing to operate the fan only wastes energy.
Window fans can also help to cool down your house in lieu of running your central air conditioning. A box fan,
or other type, placed in an open window can blow cooler outside air into a room, or set in reverse,
can draw cool air in through other windows and throughout the entire house. This, of course, is
best done when the air outside has cooled down, such as in the evening, yet the air inside the
house is still warm. Humidity conditions, pollen, dust and other factors will need to be
considered when using this approach. A window fan, or portal box fan or fan on a stand can
also be used in a fashion similar to a ceiling fan to blow air against your skin to create a
wind chill cooling effect.
- Whole house fans help cool your home by pulling cool air through the house and exhausting warm air out of the house. Typically these are very large fans installed by professionals in the attic of a home. They are most effective when operated at night and when the outside air is cooler than inside. However, allowing them to continue to run when outdoor temperatures are hotter than indoors, defeats the purpose and will waste energy. Again, humidity conditions, pollen, dust and other factors will need to be considered when deciding to use this approach.
For more information on cooling your home through fresh air ventilation techniques, go to:
ENERGY STAR ceiling fans
Department of Energy ventilation systems Information
Look for ENERGY STAR Products
Almost half of your home's energy use is from products you plug into the wall. You can find ENERGY STAR qualifying products for many of these products as products in over 60 different product categories now qualify for the label and offer significant savings over typically purchased products. You can start making improvements by simply purchasing energy efficient lighting and appliances labeled as ENERGY STAR. The following web pages provide additional information
ENERGY STAR lighting bulbs and fixtures - Learn about energy efficient light bulbs,
fixtures (across a range of technologies), and decorative light strings (holiday lights).
ENERGY STAR Appliances - Learn about energy savings from clothes washers, dehumidifiers, dishwashers, refrigerators & freezers, room AC, and room air cleaners.
ENERGY STAR Home Electronics - Learn about energy saving battery charging systems, digital-to-analog converter boxes, cordless phones, combination units, DVD products, external power adapters, home audio, televisions, and set-top boxes.
ENERGY STAR Office Equipment - Learn about energy saving computers, copier and fax machines, digital duplicators, notebook computers/tablet PCs, mailing machines, monitors/displays, water coolers, printers, scanners, and all-in-Ones.
ENERGY STAR Water Heaters - Learn about various energy efficient water heater technologies and the ENERGY STAR specification for each water heater type.
Consider a Whole House Retrofit
Some homeowners, frustrated by high energy bills and uncomfortable homes, undertake a comprehensive solution to their energy efficiency problems. Rather than focusing on a single component, such as replacing single-paned windows, an old air conditioning system, or leaky ductwork, a qualified contractor will examine how improvements to all of these components can work together to provide greater comfort and lower utility bills. By focusing on the whole house as a system the contractor can provide the most cost-effective recommendations to improve the home. For example, a contractor may air seal and insulate a home. If this is done properly, the home will not require as large of a heating or cooling system, saving the homeowner money if replacing the system. Added benefits occur if the ducts are sealed and energy efficient windows are installed. The contractor, using special diagnostic tools, can recommend the right set of improvements to achieve the most energy savings for the least cost.
EPA, in conjunction with the Department of Energy, oversees a comprehensive retrofit program called Home Performance with ENERGY STAR. A video of Home Performance with ENERGY STAR to see what to expect from a whole house assessment may be viewed at http://www.energystar.gov/index.cfm?fuseaction=mesa.showLogin
What else can you do?
There are several additional ways to improve the energy efficiency of your home.
Over 90 percent of the roofs in the United States are dark-colored. These low-reflectance surfaces reach temperatures of 150 to 190°F (66 to 88°C) during hot weather and contribute to increased cooling energy use and higher utility bills. In contrast, lighter-colored "cool roofs" with high reflectance and emissivity can stay up to 70°F (39°C) cooler than traditional materials during peak summer weather. Benefits of cool roofs include reduced building heat-gain and saving on summertime air conditioning expenditures. By minimizing energy use, cool roofs do more than save money they reduce the demand for electric power and resulting air pollution and greenhouse gas emissions. An ENERGY STAR qualified roof decreases the amount of heat transferred into your home
You can increase the energy efficiency and reduce the climate impact of your home by taking advantage of the natural light windows and skylights can bring in, often referred to as "daylighting." Daylighting is simply the use of natural sunlight to brighten up and warm a home's interior. Today's highly energy-efficient windows, as well as advances in lighting design, allow of windows to reduce the need for artificial lighting during daylight hours without causing heating or cooling problems. The more natural light available, the less we have to rely on energy to run light fixtures. Daylighting also helps improve your home's aesthetic feel. Using light-colored wall paints can also help brighten up a room and reflect more daylight throughout the space.
For more information on daylighting, go to:
Supplemental Heating Sources
You can increase the energy efficiency and reduce the climate impact of your home by taking advantage of the natural light windows and skylights can bring in, often referred to as "daylighting." Daylighting is simply the use of natural sunlight to brighten up and warm a home's interior. Today's highly energy-efficient windows, as well as advances in lighting design, allow for windows to reduce the need for artificial lighting during daylight hours without causing heating or cooling problems. The more natural light available, the less we have to rely on energy to run light fixtures. Daylighting also helps improve your home's aesthetic feel. Using light-colored wall paints can also help brighten up a room and reflect more daylight throughout the space.
A wood stove can be a significant source of supplemental heat in your home and another way for you to save money on your energy bills. Today's wood stove models feature improved safety, efficiency and lower emissions. If installed and operated correctly, they produce almost no smoke, minimal ash, and require less firewood than older models. They can be sized to heat a family room, a small cottage, or a full-sized home.
However, woodstoves take time and effort and a steady supply of wood for fuel. If you buy it, firewood can be expensive in some locations and a chore to store and transport into the house. Wood stored inside the house can lead to insect problems. Wood stoves need considerable attention to ignite and operate correctly and the ashes need to be carefully cleaned out periodically, which can be a messy job. If not operated correctly, wood stoves can generate smoke and other pollutants that can lead to poor indoor air quality.
If you are willing to take on these challenges, a wood stove may be a good choice for you to help reduce your traditional heating costs.
For more information to help you choose an EPA certified wood stove or fireplace insert, or another cleaner burning hearth appliance (e.g., gas or pellet stove), go to: http://www.epa.gov/burnwise/woodstoves.html
You should never smell smoke in your home when using a wood stove. Also, any smoke that escapes from your wood stove unburned is wasted fuel that will stick in your chimney as creosote or be released as air pollution. The odor of smoke in your home indicates that your wood stove is not operating efficiently or safely and may lead to indoor air quality problems.
For more information about wood burning efficiency and safety, go to:
Fireplaces are not very energy efficient. Although a fire in an open fireplace may provide ambience, an open fireplace typically draws more heat out of a house than it provides. To save energy, keep your fireplace damper closed unless a fire is going. Keeping the damper open is like keeping a window wide open during the winter; it allows warm air to go right up the chimney. When you use the fireplace, turn down your thermostat for the rooms warmed by the fire.
Water heating is one of the largest energy expenses in your home, after space heating and cooling, which are the first and second largest expenses, respectively. You can reduce your monthly water heating bills by selecting an efficient water heater for your home or pool-such as tankless, heat pump, or solar hot water heaters-and by using some energy-efficient water heating strategies.
For more information on energy efficient hot water heaters, including how they work and whether one might be right for your home, go to:
Water Heating Strategies
One of the easiest ways to cut your water heating bills is to insulate your older hot water heater and your hot and cold water pipes.
For more information on hot water heater and pipe insulation, go to:
EPA, through its ENERGY STAR Program, offers homebuyers a comprehensive solution to energy efficient
new construction that delivers better performance, greater comfort, and lower utility bills to homeowners.
EPA estimates that an ENERGY STAR qualified home saves between 20% to 30% more energy than a home built to the
national energy code. Take a tour "Behind the walls"
to understand how energy efficient technologies and the comprehensive approach delivers energy savings to home
buyers. Also, an ENERGY STAR qualified home uses tried and true technologies and easily applied construction
processes for builders.
Features of an ENERGY STAR qualified home include:
- Effective insulation
- High performance windows
- Tight construction and Ducts
- Efficient heating and cooling equipment with proper home ventilation
- Efficient Products (water heating, lighting, and appliances)
- Third party verification that the home was built correctly
Passive Solar Heating
While home construction can incorporate many technologies to help homeowners save energy, there are additional
measures you can design into your home to take advantage of solar energy without installing solar collectors
on your roof. Some existing homes can also take advantage of passive solar heating. Buildings that use
passive solar design need fewer or smaller-scale active technologies to meet the remainder of their heating
and lighting needs (i.e., smaller mechanical heating systems). Because the sun's energy is free, maximizing
use of passive solar techniques before adding active technologies can significantly reduce your energy bills.
Work with your architect to incorporate the following into your blueprints.
Design elements of passive solar heating (and cooling) include:
- House orientation (south-facing windows)
- Vegetation/trees for shading and wind breaks
- Another simple strategy is to plant deciduous trees near south, east, and west-facing windows,
which will provide needed shade in the summer, but let in the sun's heat during the winter
(when the leaves have fallen). Also, evergreen trees on the north side of your home can
help buffer winter winds.
- Use the sun's heat - During the heating season, open curtains on your south or west-facing windows
during the day to allow sunlight to naturally heat your home, and close them at night to reduce
any chill. (During the cooling season, keep your window coverings closed during the day to
prevent solar gain.)
- Thermal mass materials - These materials retain or store heat produced by sunlight or other sources.
They are typically dense materials such as stone, concrete, or metal, and are often an important component
of solar heating systems and other high efficiency systems
- When building a new home or planning a major addition, consider orienting windows to the south. You can also use roof overhangs to help reduce energy use by providing shade from the sun in the summer and solar heat gain in the winter
For more information on passive solar heating and how it works, go to:
Because building codes continue to increase in stringency and housing technology continues to improve, the specifications for ENERGY STAR continue to move to more stringent specifications. While the following technologies are not required for an ENERGY STAR qualified home, the role of these technologies may increase to make ENERGY STAR homes even more energy efficient in the future. EPA has developed a program called Climate Choice that incorporates advance new home construction into homes that can save approximately 50 percent more energy than a home constructed to the model energy code (2006). These are the next generation of technologies that will help those home owners reaching for a carbon neutral home. These technologies are described in more detail at http://www.epa.gov/cppd/climatechoice
Super Insulation Wall Systems
Insulation is typically described in terms of R-value. However there is much more that goes into effective insulation including zero tolerance installation, a complete air barrier and the elimination of thermal bridging through the walls. The following technologies are important components of a super insulated wall system.
Conventional Framing with Rigid Insulation Sheathing
This wall system uses conventional framing and insulation between the studs, but with a complete air barrier formed on the outside with rigid insulation.
Double Framed Walls
Two sets of conventionally framed walls are constructed with offset vertical framing. This framing eliminates thermal bridging except at the top and bottom plates. This type of framing allows room for additional insulation for increased R-Value.
Structural Insulated Panels
Structural insulated panels (SIPs) are prefabricated insulated structural panels for use in building walls, ceilings, floors, and roofs. They provide superior and uniform insulation compared to more traditional construction methods (stud or "stick frame"), offering energy savings of 12-14 percent.
Insulating Concrete Forms
Homes built using an insulating concrete form (ICF) system literally have the insulation built into the walls as part of the structure. This system creates walls that have a high thermal resistance, with R-values typically above R-17. Even though ICF homes are constructed using concrete, they can look just like traditional stick-built homes.
Super Efficient Windows
High Performance windows today feature soft-coat low-E coatings, inert gas in a vacuum sealed air gap, warm edge spacers and more efficient frame technology. The results are windows that block over 70 percent of the solar heat gain and provide overall R-3 thermal resistance. The most efficient windows today enhance performance further with one or two additional low-E glazing layers, gas filled insulating gaps and more efficient framing
Air-Tight Air Handlers with High Efficiency with High-Efficiency Variable-Speed Fans
Research indicates that approximately half of duct losses occur in the air handler because these products are very leaky. Manufacturers of air-handlers are beginning to offer air-tight cabinets by sealing joints and using gaskets at access door panels. High efficiency speed fans would further increase the overall efficiency of the system.
Solar Domestic Water Heating System, De-superheater, or Heat Pump water Heater
These advances in water heating will become increasingly important as heating and cooling loads decrease with advance new construction components.
Super High Efficient HVAC Equipment
Commercially available super efficient heating and cooling equipment include SEER 18 cooling, 9.0+ HSPF heat pumps and 95% AFUE furnaces. When heating and cooling are substantially minimized with advanced wall systems, more expensive but highly efficient geothermal heat pump systems can become cost-effective.
Active Solar Heating
When passive solar heating is not enough, supplemental heating can be provided by active solar technologies.
Small scale solar space heating systems often use a solar collector that concentrates heat in either a liquid or
in the air which is then distributed throughout the home.
Active solar heating systems are cost-effective when they are used for a large part of the year, that is, in cold climates with good solar resources. They are most economical when displacing more expensive heating fuels, such as electricity, propane, and oil heat. Certain tax credits are also available for solar home heating technologies.
For more detailed information on these technologies, go to:
Additional information maybe found at:
Your home's purchased electricity use can be a significant source of air pollution and greenhouse gas emissions. Using green power, a subset of renewable energy, can help reduce your home's environmental impact while also providing a number of other valuable benefits. Green power is electricity produced from a subset of renewable resources, such as solar, wind, geothermal, biomass, and low-impact hydropower.
Homeowners can purchase green power through three options:
Green Power Utility Product
Homeowners can check with their local electricity service provider to see if they offer a green power product. Currently, more than 850 utilities, or about 25 percent of utilities nationally, offer green power products to customers. These products allow customers to purchase some portion of their electricity from renewable resources-almost always at a higher price, but sometimes offered with price-hedging benefits.
Renewable Energy Certificates
Regardless of whether a homeowner's utility offers a green power product, any consumer in the U.S. can buy green power through renewable energy certificates, also known as RECs. RECs are the environmental benefits associated with renewable energy generation and are sold by renewable energy certificate marketers and are separate from your existing electricity service.
Homeowners can use EPA's Green Power Locator to find a list of local utilities and renewable energy certificate marketers that sell green power products in their state.
A homeowner can also investigate the option of installing an onsite energy generation system on their residence. On-site energy generation systems include such systems as photovoltaic (solar panels), wind generators, and other types of renewable energy technologies. Combining on-site renewable energy generation with energy efficiency improvements that reduce a home's energy load helps ensure that an installed system is properly sized. Further, the energy cost savings produced by energy efficiency improvements can be used to offset the purchase and installation costs of renewable energy generation systems and thus shorten payback periods.
On-site renewables provide advantages of reliability and price stability. In addition, when on-site renewables generate more power than is needed on site, many states allow the excess power to be returned to the electric grid for credit from the local electric utility. This process is known as net-metering. A variety of tax credits are available for on-site generation systems at the federal level; additional incentives are available from some states and localities.
Organizations and homeowners can learn more about these green power options by downloading "The Guide to Purchasing Green Power," from the EPA Green Power Partnership Web site. The guide helps explain the buying process as well as the benefits of each product option.
EPA strongly encourages homeowners who want to purchase green power to purchase green power products that are certified by an independent third party as a matter of best practice. Certification helps ensure the quality of green power products, and also helps build consumer confidence in the marketplace.
For more information on green power for your home and incentive programs, go to:
EPA Green Power Partnership
EPA Green Power Locator
Database of State Incentives for Renewables and Efficiency
Solar Energy Industry Association's FindSolar.com tool: Homeowners can use this tool to estimate their system need and identify local developers
Department of Energy's Energy Efficiency and Renewable Energy