One of the larger gaps in an effective home energy efficiency strategy are windows. In summer, solar energy in the form of sunlight streams through glass and heats the indoors, causing your air conditioner to run longer cycles and cooling costs to rise. In winter, furnace heat is readily lost through glass to the colder outdoors and your heating bills increase. Unstable temperature control and fluctuating comfort are additional side effects of heat gain and loss through windows.
Window treatment options can help reduce two-way heat transfer through glass. By increasing energy efficiency, costs decline and indoor comfort benefits.
Window Coverings
Blinds are available as horizontal slats or the vertical format. Closed blinds block a substantial percentage of sunlight and cut heat gain in summer. Because of the openings between slats, however, blinds are not as effective to reduce heat loss in winter.
Curtains and drapes vary in effectiveness to reduce heat transfer. The color and type of fabric used is a major factor. Medium-colored drapes with plastic backing in a neutral color can reduce summer heat gain in a room by fully one-third. During cold weather, closing drapes in a room overnight can prevent about 10% of heat loss through the window.
Window Films
Transparent polyester film that adheres to windows can add an insulating factor to glass without having to close shades or blinds. The newest varieties of window film can block more than 50% of incoming solar heat gain while still admitting over 80% of visible light. Window films also reduce heat loss during winter, keeping living spaces warmer in cold weather.
The primary ratings for window films are Solar Heat Gain Coefficient (SHGC) and Visible Transmittance (VT). Both are expressed as decimal figures between zero and one. The lower the SHGC rating, the less solar heat the film allows to pass through the window. A higher VT percentage means more visible light is transmitted.
Ask Paitson Bros. for more about window treatments that boost energy efficiency without upgrading the HVAC system. We’ve been your source for effective heating and cooling alternatives since 1922.
Our goal is to help educate our customers in Terre Haute, Indiana about energy and home comfort issues (specific to HVAC systems). For more information about other HVAC topics, download our free Home Comfort Guide or call us at 812-645-6859.
Paitson Bros
1 (812) 232-2347
Serving the Wabash Valley, IN Area Since 1922