Air conditioning is blissful during the summer, but running it nonstop during a heat wave will have you cursing when you get your utility bill. Fortunately, clever use of blinds, curtains, and other window treatments can help keep your house cool and your bills in check. The Department of Energy says that smart management of window coverings can reduce heat gain by up to 77 percent. And, as a bonus, these same practices can reduce heat loss in the winter. Here are some energy-saving suggestions from the DOE that'll pay off immediately.

Awnings. Window awnings can reduce solar heat gain by up to 65 percent on south-facing windows and 77 percent on west-facing windows, according to the DOE. For best results choose awnings in light colors that reflect more sunlight. In the winter, you can roll up retractable awnings to let the sun warm up your house.

More on Keeping Cool This Summer

Curtains and drapes. On summer days, keep your curtains closed. "Particularly on the side of the house or apartment where the sun is coming in," says Allen Drury, a representative of Con Edison.

The ability of curtains and drapes to reduce heat gain depends on fabric type (closed or open weave) and color. Studies show that medium-colored draperies with white plastic backings can reduce heat gain by 33 percent, according to the DOE. Hang the curtains as close to the window as possible. For maximum effect, install a cornice at the top of the draperies, seal the draperies at the sides, and overlap them in the middle using Velcro or tape.

Shades. When properly installed, window shades are one of the simplest and most effective ways to save energy, but they need to be drawn all day to work. Mount them as close to the glass as possible within the window frame, creating a sealed space. Reversible shades that are white on one side and dark on the other can be switched with the seasons with the white side reflecting the sun in the summer and the dark side absorbing it in the winter.

Quilted roller shades and Roman shades with several layers of fiber batting act as both insulation and an air barrier and are more effective than other soft window treatments.

Blinds. Because of the horizontal slats, it's difficult to control heat loss through interior window blinds, although they do offer some flexibility. Unlike shades, you can adjust the slats to control light and ventilation. When completely closed, highly reflective blinds can reduce heat gain by around 45 percent, says the DOE. They can also be adjusted to block and reflect direct sunlight onto a light-colored ceiling, which diffuses the light without much heat or glare.

Reflective films. Window films are best for homes in regions with long cooling seasons. Silver, mirror-like films typically are more effective than colored, more transparent films, and east- and west-facing windows benefit most because of their greater potential for heat gain. Keep in mind that reflective films are tricky to clean and may affect your view.

Learn how to size a window air conditioner for more information, and check our air conditioner ratings and recommendations for more choices.

If You Really Need A/C

You should also take the heat of the sun into consideration when installing a window air conditioner. If you place the unit in a window that gets direct sunlight during the hottest part of the day, it will have to work harder to keep you cool. And that'll cost you. Here are some top performers from our air conditoner tests listed by the size room that they're best suited for.

Small (100 to 300 square feet)

Medium (250 to 400 square feet)

Large (350 to 650 square feet)

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