ENERGY EFFICIENCY EnergyServices FACT SHEET June 2006 Energy efficiency and indoor air quality imiting uncontrolled air leakage in your home is one If you think you have an indoor air quality problem, a of the most cost-effective ways to reduce energy use. two-pronged strategy is recommended. A well sealed home may also eliminate transfer for L First, limit the source of indoor air contaminants. moisture from the interior of the home to the building Reduce or eliminate contaminants from your home. components, reducing the chances of rot or frost damage. A tight building shell can reduce the amount of dust, pollen Second, further reduce the level of indoor air or other contaminants that enter the living space. Most of contamination by providing a consistent and reliable all, a tight home puts the occupant in control of the ventila- level of ventilation. tion of the building. With the right ventilation strategy, the occupant can select when and where outdoor air enters the home. Individual To take advantage of the benefits of house tightening sensitivity without adversely effecting indoor air quality the occupants need to take an active role in keeping the indoor air clean. The air inside a home contains substances that can potentially be either harmful to human health or damaging to the building itself. If one or more of these substances became concentrated enough, the home can have poor Pollutant indoor air quality. By limiting the sources of indoor air source Ventilation contamination and providing an appropriate level of strength ventilation, an occupant can maintain a healthy indoor environment. Air filters effective at removing particulates ilters can be effectively used to remove self-contained units can be effective at capturing particulates from the air. But most filters available particulates in a single room. Filtration units for use in F to homeowners are not effective at removing central heating systems can also be effective. But central other contaminants. While these filters are effective systems need to be sealed exceptionally well to assure at reducing the quantity of pollens, spoors or pet they are not simply bringing more contaminants into dander, they do not work very well for chemicals like the home. formaldehyde or cleaning products. For a complete review of residential air cleaning To be effective, filters must be efficient at capturing equipment read “Residential Air Cleaning Devices: small particles, move relatively high volumes of air Types, Effectiveness and Health Impact” available from and should capture and distribute air widely. Portable the American Lung Association at www.lungusa.org. Ventilation Ventilation is an important part of maintaining indoor air quality. To maintain a healthy indoor environment, it is recommend that at least 35 percent of the indoor air be exchanged with outdoor air every hour. For a typical 1,800-square-foot house, this is a volume R-4 of 85 cubic feet of air per minute. Insulation If a home is not well sealed, wind and temperature differences would ventilate the home naturally. But it would be difficult to control the ventilation rate. In the winter, the home would over-ventilate, leading to high energy bills. When the weather is moderate, as is the case in much of the spring and fall, natural ventilation would not be enough. High quality exhaust fan The source of natural ventilation would also be difficult to control. In leaky homes, the source of new air frequently Ventilation integrated comes from the basement or crawl space where undesirable with a forced-air heating system molds, radon or household chemicals may be present. By adding a fresh air intake to the return air duct of a forced-air heating system, a forced-air furnace can be used Stale air to Fresh air to outside building to provide whole house ventilation. A timer controls the furnace fan motor, as well as an automatic damper attached to the intake duct. These systems use about twice as much energy as simple exhaust fans described above. Heat recovery ventilation Heat recovery ventilation systems can reduce the energy Fresh air from outside Heat Stale air impacts of providing fresh outdoor air to a home. Models exchange from building vary. Some can be integrated with a forced-air heating Heat recovery ventilation system. Others require an independent set of ductwork The recommended strategy for controlling the ventilation to distribute fresh air throughout the home. The simplest rate of a building is to construct a tight building shell and models are much like a window mount air conditioner. Heat provide appropriate ventilation levels. Because opening recovery ventilators are most cost effective in cold climates, and closing windows can not always provide appropriate or when exceptionally high volumes of ventilation are ventilation levels, mechanical ventilation systems are required. recommended. For many homes a mechanical ventilation system may simply be a high-quality bath fan. In homes with Screened fresh air forced air heating or cooling, ventilation can be incorporated intake grille into the ductwork. In cold climates, sophisticated heat Insulated duct recovery ventilation systems may be desirable. Heat recovery ventilation systems can provide prescribed volumes of Damper ventilation without significantly increasing the winter heating requirements of the home. Ventilation systems provide appropriate volumes of fresh air to the home regardless of the weather. This puts the homeowner in control of indoor air quality. Air return side of heating system Exhaust fans 24-hour timer with A new generation of high-quality bath fans is now available. on/off switch wired parallel to furnace They are quiet, use less energy and are rated for continuous fan and damper operation. As well as keeping the moisture out of the bath, they Furnace can be run for much of the day to provide whole house ventilation. Ventilation integrated Timers or other automatic controls operate the fan eight hours or with a forced-air furnace more each day to provide the desired ventilation level. 2 Major household pollutants Moisture Particulates Moisture is not typically viewed as an indoor air Particulates are particles (both solids and liquids) contaminant, but it does have an effect on indoor air suspended in indoor air in varying sizes and of various quality. It can influence the emission rate of some other composition. Both organic and inorganic materials are pollutants, for example, formaldehyde. In addition, found in the air, including pollens, spores, microbes, condensation on building surfaces can sponsor the asbestos fibers, insect debris, food remnants and pet growth of fungi and promote microbial contamination. dander. Those particles small enough to be inhaled are Dust mites grow most readily in moist environments. known as respirable suspended particulates and are of To reduce indoor moisture, make sure bath, kitchens particular importance. Some are harmful in themselves. or other sources of moisture are well vented to the Others can carry harmful substances, such as radon outdoors. If your home has a crawl space, make sure the progeny, into the lungs. Measurement is relatively ground is covered with a black, 6-mil plastic sheet. difficult. You can control particulates through source control, specialized filtration and air cleaning. Radon Radon is a radioactive gas continuously being Combustion products created by the radioactive decay of radium, a naturally Combustion products can enter the indoor air from occurring metallic element that exists in all soils in unvented or improperly vented combustion appliances, varying concentrations. Radon sources can include such as unvented kerosene heaters, gas ranges, furnaces, soil, ground water and earth- or rock-based building water heaters, woodstoves and even cigarettes. The materials. Radon lasts just a few days before it decays major products of concern are carbon monoxide, into other radioactive elements which are solid particles. nitrogen oxides and RSP. Carbon monoxide is an These radon “progeny” can be breathed into the lungs, odorless, colorless gas that impairs the blood’s ability where they are likely to attach to the lung lining and to carry oxygen. Carbon monoxide is lethal at higher decay again, exposing the lungs to radiation. Radon concentrations. Nitrogen dioxide is a colorless gas with a is associated with lung cancer. The Environmental pungent odor that can damage the lungs and cause lung Protection Agency estimates that radon causes about disease. To control these pollutants, you must properly 14,000 lung cancer deaths each year. You can easily install, use and maintain vented appliances. Unvented measure radon concentrations in the home and combustion appliances are major pollutant sources. You effectively reduce them using radon proof construction should use them with caution only in well-ventilated methods. Radon is not found in all geographic locations. areas. Check with your local health department to see if radon is a problem in your area. Organic compounds Hundreds of different organic compounds are found Formaldehyde in household products, and the full range of potential Formaldehyde is a very reactive chemical used in health effects is very large. Health effects range from eye, many household products, including particleboard, nose, throat and skin irritation to an increased risk of hardwood plywood, furniture, drapes, carpet pads and cancer. Some products may cause headaches, dizziness urea-formaldehyde foam insulation. Formaldehyde or nausea. Pesticides, aerosol sprays, carpets, synthetic outgases from these and other materials for many years, plastics, adhesives and cleaning agents are a few though the amount of outgassing decreases over time. examples of organic compounds. To control potential In gaseous form, it is very pungent and an irritant to problems, learn more about the chemical composition eyes, nasal passages, lungs and skin. Formaldehyde is of products substitute less hazardous products and use currently classified as a potential carcinogen. Control and store these products as instructed. Limit their effect strategies include source removal, source reduction and on indoor air quality by ventilation.