Window coverings with a glimpse of the sun.

Air conditioning might feel blissful during the height of summer, but running it nonstop during a heat wave will have you boiling 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 will 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.

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 Allan Drury, a spokesman for Con Edison, an energy company.

More on Keeping Cool

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 Film

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, obviously, may affect your view.

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 the best small, medium, and large window ACs from CR's air conditioner tests, plus the top portable model. For even more options, see our complete air conditioner ratings.

Quick Take

LG LW6019ER

Price: $270

Comfort
Brownout
Indoor noise high
Unlock Air Conditioner Ratings
Quick Take

LG LW8019ER

Price: $400

Comfort
Brownout
Indoor noise high
Unlock Air Conditioner Ratings
Quick Take

LG LW1217ERSM

Price: $450

Comfort
Brownout
Indoor noise high
Unlock Air Conditioner Ratings
Quick Take

Whynter ARC-12SDH

Price: $460

Comfort
Brownout
Indoor noise high
Unlock Air Conditioner Ratings

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