What Are the Benefits of Energy-Efficient Windows?

Features

• Manufacturers offer a variety of energy-efficiency features. Double-paned windows contain a thin layer of gas sandwiched between two glass panes, reducing the rate at which the window conducts heat. The gas in the middle layer may be air, or it could be an inert gas like argon or krypton. Windows may also feature glazed coatings that reflect infrared radiation into the home in winter and reflect it back to the outdoors in summer. They may also be designed to prevent air from leaking through chinks and crannies around the frame; a better-sealed window will prevent leakage and thereby reduce the amount of heat lost in winter or gained in summer. The choice of framing material is another important factor as well. Frames made from wood or fiberglass are better insulators than frames made from metal.

Savings

• High-performance windows may cost more than windows lacking these additional features, but they can save you money by reducing your heating or air-conditioning bill. The Efficient Windows Collaborative estimates that the installation of high-performance windows in a typical 2,150 square foot house in Boston can save the homeowner from 16 to 26 percent annually on heating bills, depending on the type of windows chosen and the features they incorporate. High-performance windows used in warm climates offer similar savings.

Comfort and Quality of Life

• An energy-efficient window can reduce unwanted drafts. When a home loses heat through a window, cold air at the window sinks while warm air from around your body rises, creating a convection loop that can make you feel even colder than you really are. By minimizing the rate of heat exchange with the outside, a high-performance window avoids this effect and helps keep you warm in winter and cool in summer. Windows with multiple panes can also help to reduce or block noise from outside and improve air quality by preventing dusty or dirty air from leaking in.

Other Considerations

• Many manufacturers offer extended warranties on energy-efficient windows -- a plus in case anything does go wrong with your window's performance or installation. The glazings on many high-performance windows can help block ultraviolet light, which reduces fading on carpets, upholstery and furniture. Moreover, in the wintertime, homes with high-performance windows typically stay warmer than homes with windows of a more traditional design, resulting in a drier interior environment and reduced condensation.