Elements of an Energy-Efficient House
You have much to consider when designing and building a new energy-efficient house, and it can be a challenge. However, recent technological improvements in building elements and construction techniques also allow most modern energysaving ideas to be seamlessly integrated into house designs while improving comfort, health, or aesthetics. And even though some energy-efficient features are expensive, there are others that many home buyers can afford. While design costs, options, and styles vary, most energy-efficient homes have some basic elements in common: a wellconstructed and tightly sealed thermal envelope; controlled ventilation; properly
DOE/GO-10200-1070 FS-207 July 2000
This house in Illinois has many energy-efficient features, including advanced framing techniques, insulated sheathing, and an advanced ductwork system. It was built by Town and Country Homes as part of DOE's Building America Program.
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This document was produced for the U.S. Department of Energy (DOE) by the National Renewable Energy Laboratory (NREL), a DOE national laboratory. The document was produced by the Information Services Program, under the DOE Office of Energy Efficiency and Renewable Energy. The Energy Efficiency and Renewable Energy Clearinghouse (EREC) is operated by NCI Information Systems, Inc., for NREL / DOE. The statements contained herein are based on information known to EREC and NREL at the time of printing. No recommendation or endorsement of any product or service is implied if mentioned by EREC. Printed with a renewable-source ink on paper containing at least 50% wastepaper, including 20% postconsumer waste
Photo by Sara Farrar, NREL/PIX07134
sized, high-efficiency heating and cooling systems; and energy-efficient doors, windows, and appliances.
A thermal envelope is everything about the house that serves to shield the living space from the outdoors. It includes the wall and roof assemblies, insulation, air/vapor retarders, windows, and weatherstripping and caulking.
Wall and Roof Assemblies
Most builders use traditional wood frame construction. Wood framing is a “tried and true” construction technique that uses a potentially renewable resource—wood—
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to provide a structurally sound, long-lasting house. With proper construction and attention to details, the conventional wood-framed home can be very energyefficient. It is now even possible to purchase a sustainably harvested wood.
Foundation walls and slabs should be as well insulated as the living space walls.
Some of the available and popular energyefficient construction methods include the following: Optimum Value Engineering (OVE). This method uses wood only 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 sound 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 (SIPs). These sheets are generally made of plywood or oriented-strand board (OSB) that is laminated to foam board. The foam may be 4 to 8 inches thick. Because the SIP acts as both the framing and the insulation, construction is much faster than OVE or stick framing. The quality of construction is often superior because there are fewer places for workers to make mistakes.
Insulating Concrete Forms (ICF). Houses constructed in this manner consist of two layers of extruded foam board (one inside the house and one outside the house) that act as the form for a steel-reinforced concrete center. It’s the fastest technique and least likely to have construction mistakes. Such buildings are also very strong and easily exceed code requirements for areas prone to tornadoes or...