Walls and Roofs

This page provides information on insulation, weatherization, and other technologies designed to minimize energy loss through the building envelope.

The building envelope includes everything that separates the interior of a building from the outdoor environment: walls, roofs, foundation slab, ceiling, windows, doors and insulation. Walls and roofs come in direct contact with the elements, and form a thermal barrier between the people inside and the weather outside.

The average home wastes up to 30% of the energy used for heating and cooling due to leaks in the building envelope, many of which are usually present in the walls and roof. There are many techniques for building an energy efficient building for your climate and uses, as well as for retrofitting an existing building to make it more energy efficient. These can be as simple as caulking and weatherstripping or adding insulation to replacing windows, doors, or other components.

For further information on related technologies, see DOE's Buildings Web site.

The DOE Weatherization Assistance Program provides free weatherization services — including energy audits and insulation — for homes of low-income families. The Weatherization Assistance Program provides program contact information for each state, as well as eligibility requirements.

The following article describes weatherization projects on tribal lands:
"Weatherization in Indian Country," Conservation Update, November - December 2004

The U.S. Environmental Protection Agency (EPA) and the U.S. Department of Energy (DOE) collaborate in the Energy Star program, a voluntary labeling program designed to identify and promote energy-efficient products to reduce greenhouse gas emissions. The Energy Star Web site provides useful information on thousands of these products, including new homes and commercial and industrial buildings.

See Weatherization on DOE's "Consumer's Guide" Web site, and the insulation fact sheet provided by Oak Ridge National Laboratory.