Roofing, windows, and doors

What's new

Smarter building practices, developed for new construction, are being used to make existing homes more energy-efficient. Available in light and dark colors, cool roofs use special coated pigments to reflect sunlight and emit heat more efficiently than regular roofing. They can reduce cooling costs in warm-weather climates by 20 percent on average, according to the California Energy Commission. Daylighting, the use of windows and skylights to bring more natural light into a home while moderating seasonal temperatures, is another efficient design practice that is on the rise.

What works

Keeping heated air (and cooled air in the warmer months) from leaking out of your home's roof, walls, and windows could lower your annual energy costs by $500. Start by insulating the attic if it has less than 11 inches of fiberglass or rock wool or 8 inches of cellulose. Then seal and insulate leaky ductwork. Last, eliminate air leaks with a combination of caulk, foam board, expandable sealant, and weather stripping.

What to think twice about

Replacing windows solely for the sake of saving energy might not be a good idea. Our tests found it could take as long as 20 years to recoup that investment. But if your windows have deteriorated, or if you're replacing them as part of a larger renovation, choosing double-glazed windows with an R-value of about 2 or 3 and low-emissivity (low-E) coatings that manage solar heat gain can help trim your energy bills by 10 to 25 percent.

Energy All-Star

CertainTeed Landmark asphalt shingle, $67 per square. This laminated shingle, a CR Best Buy, showed very good strength and weather resistance in our tests, and its silver birch, mist white, and star white colors are Energy Star-qualified.