Elements of Energy Efficient House

elan vital EFFICIENCY AND RENEWABLE ENERGY Elements of an vital force- effectual Ho commit You set just about much to consider when endeavoring and create a new get-up-and-go- in force(p) foretoken, and it lowlife be a ch totallyenge. However, recent technological improvements in construction elements and construction proficiencys similarly allow well-nigh modern energy prudence ideas to be seam littlely integrated into mob designs while improving nurture, health, or aesthetics. And flush though some energy-efficient features ar expensive, in that respect atomic number 18 an otherwise(prenominal)s that m either home buyers stand afford.While design be, options, and styles vary, most energy-efficient homes give way some basic elements in common a wellconstructed and tightly seal of approvaled thermal envelope dominanceled internal respiration mighty DOE/GO-10200-1070 FS-207 July 2000 This ho theatrical role in Illinois has many an(prenominal) energy-effici ent features, including advanced inning techniques, insulated s conflagratehing, and an advanced duc iirk system. It was built by Town and Country topographic points as subprogram of DOEs construction America Program. DEP A NT OF ME EN RT ST A AT E S OF M ER This document was produced for the U. S.surgical incision of slide fastener (DOE) by the National Renewable zipper laboratory (NREL), a DOE interior(a) laboratory. The document was produced by the Information Services Program, under the DOE smudge of Energy Efficiency and Renewable Energy. The Energy Efficiency and Renewable Energy Clearingho practise (EREC) is operated by NCI Information Systems, Inc. , for NREL / DOE. The statements contained herein be based on selective selective tuition known to EREC and NREL at the time of printing. No recommendation or stock-purchase warrant of any product or service is implied if mentioned by EREC.Printed with a renewable-source sign on paper containing at least 50% barbar ianpaper, including 20% postconsumer waste ICA Photo by Sara Farrar, NREL/PIX07134 CLEARINGHOUSE GY ER sized, high gear- cleverness heat and cooling systems and energy-efficient doors, windowpanes, and appliances. Thermal windbag A thermal envelope is everything about the house that serves to shield the living space from the outdoors. It let ins the wall and roof assemblies, breakup, fashion/vapor retarders, windows, and weatherstripping and caulking. Wall and chapiter Assemblies Most builders use traditional wood frame construction.Wood framing is a tried and true construction technique that uses a potentially renewable resourcewood U N IT ED to put up a morphologically blend, long-lasting house. With proper construction and attention to details, the formal wood-framed home can be very energyefficient. It is now even true(a)izable to purchase a sustainably harvested wood. Foundation walls and slabs should be as well insulated as the living space walls. Some of the for sale and popular energyefficient construction method actings include the following Optimum Value Engineering (OVE).This method uses wood still where it is most effective, thus reducing costly wood use and saving space for insulation. The amount of lumber has been determined to be structurally blend through both laboratory and field tests. However, the builder must be familiar with this type of construction to ensure a structurally sound house. Structural Insulated Panels ( imbibes). These sheets atomic number 18 generally made of plywood or oriented-strand jury (OSB) that is laminated to froth board. The foam may be 4 to 8 inches thick. Because the SIP causes as both the framing and the insulation, construction is much faster than OVE or stick framing.The quality of construction is a great manus superior because there are a couple of(prenominal)er places for workers to substantiate mistakes. Insulating Concrete Forms (ICF). Houses constructed in this manner consist of two layers of extruded foam board (one inside the house and one out-of-door the house) that act as the form for a steel-reinforced concrete center. Its the fastest technique and least likely to have construction mistakes. Such buildings are also very strong and easily exceed tag use upments for areas prone to tornadoes or hurricanes. Insulation An energy-efficient house has much higher insulation R-values than required by most topical anesthetic building codes.An R-value is the ability of a material to stand heat transfer, and the lower the value, the faster the heat loss. For example, a typical house in raw York might have insulation of R-11 in the outside(prenominal) walls and R-19 in the ceiling, while the floors and foundation walls may non be insulated. A similar, but welldesigned and constructed house will have insulation levels that range from R-20 to R-30 in the walls and from R-50 to R-70 in the ceilings. Carefully applied fiber tripe batt or rolls, wet-spray cellul ose, or foam insulation will fill wall cavities completely.Foundation walls and slabs should be as well insulated as the living space walls. Poorly insulated foundations have a negative impact on home energy use and comfort, curiously if the family uses the lower parts of the house as a living space. Also, appliances such as domestic hot pee heaters, washers, dryers, and freezers that supply heat as a byproduct are often located in the basement. By guardedly insulating the foundation walls and floor of the basement, these appliances can assist in warming system the house. While most new houses have good insulation levels, it is often poorly installed.In general, gaps and compaction of insulation reduce its effectiveness. Photo by Craig Miller Productions, NREL/PIX02452 Air/Vapor Retarders Water vapor condensation is a major threat to the structure of a house, no matter what the climate. In cold climates, pressure differences can drive warm, moist indoor origin into out(prenom inal) walls and Workers install a structural insulated panel. 2 This house in Arizona features a passive solar design with overhangs above the atomic number 16 facing windows. The best windows are fair weatherblind and casement styles because these styles often close tighter than slide types. ttics. The walkover condenses as it cools. The same can be said for Confederate climates, just in reverse. As the humid outdoor give vent enters the walls and encounters ice chest wall cavities, it condenses into liquid pissing. This is the main reason why some buildings in the South have chores with mold and rotten wood after theyre retrofitted with aura conditioners. A vapor retarder is a material or structural element that can be used to inhibit the movement of water vapor, while an tune retarder can inhibit airflow, into and out of a houses envelope.How to design and install vapor retarders depends a great deal on the climate and on the chosen construction method. However, any wa ter vapor that does manage to get into the walls or attics must be allowed to escape. irrespective of climate, water vapor migration should be minimized by using a carefully designed thermal envelope and sound construction practices. Systems that control air and water vapor movement in homes rely on the nearly air-tight installation of sheet materials on the interior as the main roadblock. The Airtight Drywall Approach (ADA) uses the drywall already being installed along with gaskets and caulking to relieve oneself a 3 ontinuous air retarder. In addition, seams where foundation, sill plate, floor joist header, and subfloor meet are also carefully sealed with appropriate caulk or gasket material. name your local building codes mangleicial on the best vapor retarder method to use in your area. Windows The typical home loses more(prenominal)(prenominal) than 25 part of its heat through windows. Even modern windows insulate less than a wall. Therefore, an energy-efficient house i n a modify-dominated climate should, in general, have few windows on its northern, eastern, and western sides.Total window area should also not exceed 8 to 9 percent of the floor area for those rooms, unless the intriguer is gived in passive solar techniques. If this is the case, then increasing window area on the southern side of the house to about 12 percent of the floor area is recommended. This is often called solar tempering. A properly designed roof overhang for south-facing windows will help prevent heat in the summer. North, east, Photo by Sara Farrar, NREL/PIX08155 and west windows should have low solar Heat Gain Coefficients (SHGC).South windows with properly sized overhangs should have a high SHGC to allow winter sun (and heat) to enter the house. The overhang blocks the high summer sun (and heat). If properly sized overhangs are not possible, a low SHGC glass should be selected for the south windows. At the very least, you should use windows (and doors) with an Energ y Star distinguish, which are twice as energy efficient as those produced 10 years ago, according to regional, climatic guidelines (note houses with any mannikin of solar tempering have other guidelines).The best windows are awning and casement styles because these often close tighter than sliding types. In all climates, window glass facing south without overhangs can cause a problem on the cooling side that far exceeds the benefit from the winter solar gains. when compared to other houses of the same type and age. You can accomplish most air close by using two materials caulking and weatherstripping. Caulking can be used to seal areas of potential air leakage into or out of a house. And weatherstripping can be used to seal gaps around windows and exterior doors. visualizeled Ventilation true(p) air sealing alone may reduce utility be by as much as 50 percent. Since an energy-efficient house is tightly sealed, it needs to be ventilated in a controlled manner. Controlled, mechan ical airing prevents health risks from indoor air pollution, promotes a more comfortable atmosphere, and reduces air moisture infiltration, thus reducing the likelihood of structural damage. Furnaces, water heaters, habilitate dryers, and bathroom and kitchen outsmart fans expel air from the house, making it easier to depressurize an airtight house if all else is ignored. notwithstanding natural-draft appliances may be back-drafted by tucker fans, which can lead to a lethal buildup of toxic Weatherstripping and Caulking You should seal air leaks everywhere in a homes thermal envelope to reduce energy loss. Good air sealing alone may reduce utility costs by as much as 50 percent Ceiling light fixture Electrical wires perspicacious vapor barrier reefers at attic hatch Vents from bathroom and kitchen Joints at interior partitions Joints between wall and ceiling Joints at windows Electric time Electrical service entrance Electrical panel Electrical outlets and switches quantify sta ck penetration Chimney penetration of ceiling Holes through air-vapor barrier Joint between bottom plate and floor Cracks around doors Joint between joists and basement wall Service entrance for cable TV, telephone, fuel, and so forth Air leakage can occur in many places throughout a home. 4 Heating and Cooling Systems Stale room air return Specifying the correct sizes for alter and cooling systems in airtight, energy-efficient homes can be tricky. Rule-of-thumb sizing is often inaccurate, resulting in wasteful operation.Conscientious builders and heating, ventilation, and air-conditioning contractors size heating and cooling equipment based on careful consideration of the thermal envelope characteristics. Outside air inlet Fresh air supply air-to-air heat exchanger Exhaust air Heat recovery ventilation. Generally, energy-efficient homes require relatively small heating systems, typically less than 50,000 Btu/hour even for very cold climates. Some require nothing more than sunnine ss as the primary source of heat along with auxiliary heat from radiant in-floor heating, a standard gas-fired water heater, a small boiler, a furnace, or electric heat pump.Any common appliance that gives off waste heat can also contribute significantly to the heating requirements for such houses. If an air conditioner is required, its often a small whole and sufficient for all but the warmest climates. Sometimes only a bragging(a) fan and the cooler evening air are needed to make the house comfortable. The house is closed up in the morning and waistcloth cool until the next evening. Smaller-capacity heating and cooling systems are usually less expensive to buy and operate.This helps recover the costs of purchasing more insulation, and other energy-efficient products, such as windows and appliances. Al right smarts look for the Energy moderate label on heating and cooling equipment. The label will rate how efficient it is as compared to others acquirable on the market. In climate s where summer cooling requirements dominate, light-colored materials and coatings (paint) on the exterior siding and roof can help reduce cooling requirements by up to 15 percent. Carefully selected and placed vegetation in any climate also contributes to reduced cooling and heating loads. ases in the house. For this reason, sealed conflagration heating appliances, which use only outside air for combustion and vent combustion gases directly to the outdoors, are very important for ventilation energy efficacy and safety. Heat recovery ventilators (HRV) or energy recovery ventilators (ERV) are ontogenesis in use for controlled ventilation in airtight homes. These ventilators can ease about 70 percent of the energy from the stale exhaust air and transfer that energy to the fresh air entering by way of a heat exchanger inside the device.They can be affiliated to the central forced air system or may have their own duct system. Other ventilation devices, such as through-the-wall or tr ickle vents, may be used in conjunction with an exhaust fan. They are, however, more expensive to operate and possibly more uncomfortable to use because they have no energy recovery features to precondition the incoming air. awkward incoming air can be a serious problem in northern climates and can create moisture problems in humid climates. Therefore, this ventilation strategy is only for arid climates.Other systems pull outside air in with a small outside duct on the return side of the furnace. Generally, energyefficient homes require relatively small heating systems. 5 Energy-Efficient Appliances Higher efficiency appliances provide a measure of insurance against energy prices and emit less air pollution. Appliances with relatively high operating efficiencies are usually more expensive to purchase. However, higher efficiency appliances provide a measure of insurance against increases in energy prices, emit less air pollution, and are attractive selling points when the home is re sold.Home buyers should invest in high-efficiency appliancessuch as water heaters, clothes washers and dryers, dishwashers, and refrigeratorsespecially if these appliances will be used a great deal. Because all major appliances must have an EnergyGuide label, read the label carefully to make sure you buy the most efficient appliance. To help you choose wisely, major appliances with an Energy Star label exceed the national governments minimum efficiency standards by a large percentage.Energy-efficient lighting helps keep energy bills down by producing less heat and reducing cooling requirements. Fluorescent lighting, both formal tube and compact, is generally the most energyefficient for most home applications. always through before. They may need more training if they have no experience with these systems. Building and Buying Before you start a home-building project, the building commit and its climate should be carefully evaluated to determine the optimum design and druthers fo r the house.There are energy-related computer software programs that can help with these evaluations. The design should accommodate appropriate insulation levels, moisture dynamics, and aesthetics. Decisions regarding appropriate windows, doors, and heating, cooling and ventilating appliances are central to an efficient design. Also the cost, ease of construction, the builders limitations, and local building code compliance should be competently evaluated. Some plans are relatively simple and inexpensive to construct, while others can be super complex and, thus, expensive.An increasing number of builders are participating in the federal governments Building America and Energy Star Homes programs, as well as local home energy rating programs, all of which promote the construction of energy-efficient houses. Many of these builders construct energy-efficient homes to differentiate themselves from their competitors. Construction costs can vary significantly depending on the materials, construction techniques, contractor dinero margin, experience, and the type of heating, cooling, and ventilation system chosen.Because energy-efficient homes require less money to operate, many lenders now offer energy-efficient mortgages (EEMs). EEMs typically have lower points and allow for the stretchability of debt-to-income ratios. State and local government energy offices can be contacted for study on region-specific financing. In the end, your energy-efficient house will provide you with superior comfort and lower operating costs, not to mention a higher real estate market value. The building localise and its climate should be carefully evaluated to determine the optimum design. Advantages and DisadvantagesHouses that incorporate all of the above elements of energy efficiency have many advantages. They feel more comfortable because the additional insulation keeps the interior wall at a more comfortable and enduring temperature. The indoor humidity is also better control led, and drafts are reduced. A tightly sealed air/vapor retarder reduces the likelihood of moisture and air ooze through the walls. They are also very quiet because the extra insulation and tight construction helps to keep exterior noise out better. But these houses also have some potential disadvantages.They may cost more and take longer to build than a conventional home if theres a lack of builder familiarity with new construction techniques and products available on the market. Even though the houses structure may differ only slightly from conventional homes, the builder and contractors may be unwilling to deviate from what theyve 6 Resources The following are sources of additional selective instruction on energy-efficient houses The Energy Efficiency and Renewable Energy Clearinghouse (EREC) P. O. Box 3048 Merrifield, VA 22116 1-800-DOE-EREC (1-800-363-3732) email doe. emailprotected om sack up site http//www. eren. doe. gov/consumerinfo/ EREC provides free general and tech nical information to the earth on many topics and technologies pertaining to energy efficiency and renewable energy. Lawrence Berkeley National lab Building Technologies division MS 90-3111 Berkeley, CA 94720 USA squall (510) 486-6845 telefax (510) 486-4089 sack site http//eetd. lbl. gov/btp/btp. html Provides information on past and received research in buildings energy efficiency. National Renewable Energy Laboratory The Center for Buildings and Thermal Systems 1617 Cole Blvd.Golden, CO 80401 meshwork site http//www. nrel. gov/buildings_thermal Provides information on energy-efficient buildings. Organizations American Solar Energy Society, Inc. (ASES) 2400 Central Avenue, G-1 Boulder, CO 80301 knell (303) 443-3130 Fax (303) 443-3212 E-mail emailprotected org network site http//www. ases. org A national advocacy organization dedicated to the use of solar energy in buildings. oak Ridge National Laboratory (ORNL) Buildings Technology Center P. O. Box 2008, MS-6070 oak tree Ridge, Tennessee 37831-6070 Phone (865) 574-5206 Fax Number (865) 574-5227 Web site http//www. ornl. ov/ORNL/BTC/ Provides information on research in buildings energy efficiency. Building America U. S. Department of Energy Office of Building Systems, EE-41 1000 Independence Avenue, SW Washington, D. C. 20585-0121 Web site http//www. eren. doe. gov/buildings/ building_america/ Works with the home building industry to produce quality homes that use up to 50 percent less energy without costing more to build. sustainable Buildings Industry Council (SBIC) 1331 H Street, NW, cortege 1000 Washington, DC 20005-4706 Phone (202) 628-7400 Fax (202) 393-5043 E-mail emailprotected org Web site http//www. bicouncil. org Promotes the use of energy-efficient and passive solar building design and construction. Web Sites Building Energy Software Tools U. S. Department of Energy Office of Building Technology, State and Community Programs Web site http//www. eren. doe. gov/buildings/tools_ directory/ Describes many energy-related software tools for buildings, with an emphasis on renewable energy, and energy efficiency. Efficient Windows Collaborative Alliance to Save Energy 1200 18th Street NW, Suite 900 Washington, D. C. 20036 Phone (202) 857-0666 Fax (202) 331-9588 E-mail emailprotected rg Web site http/ /www. efficientwindows. org/ Provides unbiased information on the benefits of energy-efficient windows, descriptions of how they work, and recommendations for their selection and use. Cool Roof Materials Database Lawrence Berkeley National Laboratory Web site http//eetd. lbl. gov/coolroof/ Assists with the selection of roofing materials that reflect instead of absorb the suns radiant energy. Energy Star U. S. Department of Energy and U. S. environmental Protection Agency Phone (888) STAR-YES (1-888-782-7937) E-mail emailprotected gov Web site http/ /www. nergystar. gov/ Provides lists of Energy Star-qualified products, including appliances and windows, as well as information on its energyefficient homes program. color Buildings Center of Excellence for Sustainable Development Web site http//www. sustainable. doe. gov/buildings/ gbintro. htm Provides information and links on energy-efficient buildings. (Continued on scallywag 8) 7 Continued from page 7 The Residential Energy Efficiency Database Web site http//www. its-canada. com/ reed/ Provides a wide-range of information on energy-efficient houses, including house plans.The Passive Solar pattern and Construction Handbook, M. Crosbie (ed), J. Wiley, 1997. Available for purchase from ASES (see Resources). Residential Windows A Guide to New Technology and Energy Performance, J. Carmody, S. Selkowitz, and L. Herschong, Norton Professional Books, 1996. Phone 1-800-233-4830 http//www. wwnorton. com/npb/. Insulation Fact Sheet, U. S. Department of Energy Office of Energy Efficiency and Renewable Energy, 1997. Available from ORNL in PDF and HTML at http//www. ornl. gov/roofs+walls/insulation/. Print version is available from EREC (see Resources). vitality Code Insulation Database Oak Ridge National Laboratory Web site http//www. ornl. gov/roofs/Zip/ZipHome. html Provides information by zip code on the most economic insulation levels for new or vivacious homes. Reading List The following publications provide further information about energy-efficient home elements. The list is not exhaustive, nor does the mention of any publication construct a recommendation or endorsement. Periodicals Energy Design Update. Published by Cutter Information Corporation, 37 Broadway, Arlington, MA 02474-5552 Phone (800) 964-5118 or (781) 648-8700 Web site http// www. utter. com. This monthly newsletter contains information for professionals interested in energyefficient building technologies. Product reviews appear regularly. Environmental Building News. 28 Birge Street, Brattleboro, VT 05301 Phone (802) 257-7300 Web site http//www. BuildingGreen. com. This bimonthly newsletter covers a wide variety of topics. The ledger of Light Construction. Published by Builderburg Partners, Ltd. , 932 West Main Street, Richmond, VT 05477 Phone (800) 375-5981. This monthly journal often features articles on energy conservation techniques for the home builder.Home Energy Magazine. 2124 Kittredge Street, 95, Berkeley, CA 94704 Phone (510) 524-5405 E-mail emailprotected org, Web site http//www. homeenergy. org/. Its a source of information on reducing energy economic consumption in the home. Solpan Review. Published by Drawing-Room Graphic Services, Ltd. , P. O. Box 86627, North Vancouver, BC V71 412 , Canada Phone (604) 689-1841. This bimonthly newsletter features articles on energy conservation for the building industry, including information on new products and energy-efficient practices in residential construction. Books, Pamphlets, and ReportsBuildings for a Sustainable America Case Studies, B. Miller, ASES, 1997. Available from ASES or SBIC (see Resources). Building Green in a Black & Whit e World, D. Johnston, Home Builder Press, 2000 Phone (800) 223-2665 http//www. builderbooks. com. Consumer Guide to Home Energy Savings, A. Wilson and J. Morrill, American Council for an Energy-Efficient Economy, 2000 Phone (510) 549-9914 http//aceee. org/. The Efficient House Sourcebook, R. Sardinsky, obdurate Mountain Institute. Available from SBIC (see Resources). Energy Savers Tips on Saving Energy and funds at Home, U.S. Department of Energy. Available in PDF and HTML at http//www. eren. doe. gov/consumerinfo/energy_ savers/ or print version from EREC (see Resources). Fine Homebuilding Energy-Efficient Houses, Fine Homebuilding magazine. Available from SBIC (see Resources). Moisture Control Handbook Principals and Practices for Residential and Small Commercial Buildings, J. Lstiburek and J. Carmody, Van Nostrand Reinhold Co. , 1993. Available from the Building Science Corporation at (978) 589-5100 (phone) (978) 589-5103 (fax) or http//www. buildingscience. com. 8