Of all energy consumed in the United States, approximately one-fifth is expended on the heating and cooling, lighting, and appliances of homes. The $100 billion spent each year for household energy can be minimized, sometimes with simple changes or alterations of energy usage practices.
The largest amount of energy is used for heating and cooling houses; therefore, it is a wise economic practice to determine and correct all energy losses from your home. This can be done by conducting a home audit yourself or through a professional audit.
The Manual J Load Calculation for residential winter and summer air conditioning is a procedure used during a professional audit. This method calculates heat loss and gain in homes and determines the correct load calculation which is the primary consideration in planning and installing residential heating and air conditioning systems. The Manual J Calculation was jointly developed and adopted by the Air Conditioning Contractors of America and the Air Conditioning and Refrigeration Institute.
Homeowners also can conduct a do-it-yourself audit with a moderate amount of time and effort to correct most problem areas. These areas can be found during a careful walk-through of your home. To help prioritize problems, take notes as you carefully inspect each area.
Correcting Air Flow Problems
The first determination is to discover if and where air leaks are occurring. This is one area alone that can save up to 30% in energy savings, if corrected properly. The indoor areas to check are gaps along baseboards and floor edges, and ceiling and wall junctures,. Other areas to check for drafts are window frames, electrical outlets and switch plates, weather-stripping around doors and windows, fireplace dampers, attic hatches, gaps around pipes and wires, foundation seals, and mail slots. Keep in mind that weather-stripping may need to be reapplied from time to time.
When inspecting windows and doors there are some obvious signs of leakage, such as, if they rattle or if you see daylight around their frames. Storm windows should be checked as well for breakage and fit. Windows and doors have had considerable efficiency improvements made to them in recent years and replacing old ones is often the best practice. If this, however, is not feasible, using weather-stripping and low-cost plastic sheets over windows can be very helpful.
Keep in mind that indoor air quality is also a very important issue. Although sealing openings to prevent undue loss of energy is one factor, there is also a consideration concerning "backdrafting." This happens when a home's exhaust fans and combustion appliances compete for air. Exhaust fans may pull back combustion smoke into living areas making air quality unsuitable and even unhealthy. It is important for appliances supplying heat with fuels such as natural gas, fuel oil, propane or firewood, to have an adequate amount of air. The general rule is one square inch of vent opening for each 1,000 Btu of appliance input heat. This determination should be determined by an energy professional, local utility company, or ventilation contractor.
A home's exterior should be inspected as well. Give close attention to cracks and holes in areas where two different building materials meet such as corners where brick meets with chimneys or sidings, and also at foundations. Openings around faucets, pipes, electric outlets, and wiring should be sealed with the proper material. Routine checking of the exterior caulking around doors and windows is important to maintain its effectiveness.
The insulation level in your ceiling and walls determines to a great degree the amount of heat loss in your home. The recommended minimum for your home at the time it was built may not be the current recommended amount. The amount of insulation is determined by the climate, type of heating used by the home, and the area to be insulated. The following areas should be checked:
- Examine the exposed structural frame/ceiling joists, as well as openings around pipes, ductwork, chimneys, and the hatch. Each of these areas should be insulated or caulked with the proper material. The hatch, especially if it is constructed over a conditioned space, should be insulated, weather-stripped and tightly closed. To prevent fire hazards, recessed lights should not be covered, but instead a three-inch space allowed around each light fixture (unless the fixture is rated as insulation covered). If there are electrical boxes located in the ceiling's floor, they should be sealed with flexible caulk and covered with insulation.
- Determine whether or not there is a vapor barrier with the attic insulation. The barrier should be under the insulation and can be tar paper, Kraft paper which is attached to fiberglass batts, or plastic sheeting. A vapor barrier is important to prevent moisture from passing through the ceiling. Moisture will reduce the effectiveness of insulation and even promote structural damage. If necessary, moisture can be reduced by painting interior ceilings with vapor barrier paint. It is important to vent the attic using ridge, soffit, and/or gable vents and wind-driven or electrically powered fans. Take care, as well, not to block the vents with insulation to keep air flow open.
- When determining the level of insulation of walls, choose an exterior wall and turn off the circuit breaker or inactivate the fuse for any outlets on that wall. (Test one of these outlets to make certain it is not active.) After assuring that the electricity is turned off, remove the cover plate and carefully probe the interior of the wall with a long, thin object. When some resistance is felt during the probe, it should indicate the presence of insulation. Another method to determine the presence of insulation is to make a small hole in an unobtrusive place on the wall which also should allow you to see what kind of insulation is present. Wall cavities opening into the basement or attic should be filled tightly to prevent convective loops that lose heat and cause moisture problems.
- Unheated basements should be insulated. A minimum level of R-25 under the living area flooring is recommended for most area climates. The top of the foundation wall and living area perimeter need a level of at least R19 insulation. If the basement is heated, the minimum recommended insulation for the foundation walls is also R19. Furnace ducts should be insulated; and since water heating is the second largest consumer of home energy, care should be taken to insulate water heaters and hot water pipes as well.
Electricity costs for lighting account for approximately 10% of your bill. There are many factors to consider to reduce these costs; see our document Energy Efficient Lighting for detailed information. The Alliance to Save Energy also has an excellent web site: www.ase.org/programs/residential.htm.
The Professional Energy Audit
During a professional home energy audit the auditor will conduct an examination of the outside of the house and each internal space, as well as assess past utility bills. To prepare for the audit you should do several things: 1) list existing problems or concerns you have with any part of your home, such as drafts, condensation, etc.; and 2) copy or summarize your home's energy bills for the past several years. Utility companies can provide these. The energy audit will take into consideration the structure's features such as its size, the number of windows and doors, seasonal thermostat settings, each room's amount and time of use and many other related factors. Benefits of a professional audit include accuracy and possible immediate energy conserving measures at the time of the audit.
Professional auditors may conduct a blower door test to find a home's air infiltration rate. A strong fan mounted into an exterior door's frame pulls air out of the house. This lowers the air pressure inside and causes higher outside air pressure to flow through all unsealed openings and cracks. This useful information is used to correct air leakage, moisture condensation, drafts, and possible indoor air pollution problems. If you have a blower door test, request that the auditor use a "calibrated" rather than an "uncalibrated" door. The calibrated blower door uses several gauges to quantify the air pulled by the fan and the air sealing effectiveness. The uncalibrated blower door locates leaks only and does not determine the tightness of the home.
A thermographic inspection or infrared scanning test may be used to determine thermal defects and any air leakage in your home. This is done with use of an infrared video and still cameras which see light in the heat spectrum. Thermography can determine whether or not insulation is needed or if it has been installed correctly.
If you want or need information concerning residential energy efficiency, there also are organizations which can be helpful. The Residential Energy Services Network is dedicated to the promotion of residential energy efficiency through home energy rating programs which contain financing for energy efficiency improvements. It is a broad spectrum membership national organization comprised of various housing, consumer, and financial entities working to promote residential energy efficiency and affordability. One of their most important contributions to the residential energy efficiency field is the development of voluntary national guidelines to standardize home energy rating methods.
Other organizations such as the Energy Efficient Building Association (EEBA) and Affordable Comfort, Inc. should be good resources for consumers nationwide to find qualified residential energy auditors. Affordable Comfort, Inc. and the Energy Efficient Building Association promote residential efficiency through the dissemination of information and training, and both should be good sources for contacting technically reliable residential energy auditors.
There are some preliminary steps that should be taken before contracting with any company for the audit:
Contact at least three references for each company you consider. Ask about the auditor's work and the home owner's level of satisfaction.
Contact the Better Business Bureau and local utility regarding any records, complaints, etc. of the company's reputation.
Insist that the auditor use a calibrated blower door for the most accurate and effective assessment.
- Ask for a thermographic inspection. In some instances, it may be necessary to contract another company for this.
These precautions should allow an effective and very helpful determination of your home's energy efficiency needs. You can expect new energy efficiency procedures to contribute toward both money saved and comfort enjoyed.
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The MEA has a quantity of booklets entitled, "ENERGY SAVERS: Tips on Saving Energy & Money at Home." If you would like a copy, e-mail firstname.lastname@example.org or call 1-800-72-ENERGY.