Cooling down without paying up

Try these five ways to drive heat out of your house this summer -- none involving an air conditioner

May 19, 2007|By ROB KASPER

I love air conditioning. On hot, humid days I blow kisses to my compressor. But with meteorologists predicting an especially brutal summer and electricity rates nearly double what they were last year, I am telling myself that I am going to have to love air conditioning less. It's finally time to wean myself away from the omnipresent hum of the A/C and find other ways to cool the house.

I have scoured Web sites, looking at shades that block sunlight and at fans that move air. I have learned to appreciate trees; especially those planted on the south and west sides of a house. And I have learned new words, such as "thermosiphoning."

And I have read a number of government-issued missives on surviving summer without a hefty electric bill. The best was "Cooling Your Home Naturally," a document produced for the U.S. Department of Energy by the National Renewal Energy Laboratory.

There was a lot of advice I avoided, such as don't put windows in your house that face east and west. During the summer months, windows facing these directions let in a lot of hot sunlight, which heats up a house.

All of the windows in my Baltimore rowhouse face east or west, and I can't move my house. Instead, I have looked around for cheaper ways to keep from sweltering without switching on the air conditioner. I found five, mostly involving blocking the sun, or moving air.

1. Hanging an awning

The theory behind awnings is simple. They create shade, usually on the outside of windows, by blocking direct sunlight. A properly installed awning can reduce heat gain by 65 percent on southern windows and 77 percent on eastern windows, the DOE says.

Awnings have been popular around Baltimore for a long time. "They came into vogue in the pre-air-conditioning era, and now with electricity rates climbing, they are coming back," says Rob Lynch, who works at Loane Brothers, one of a number of Baltimore-area awning companies.

An awning for a normal side window costs between $250 to $350, he says, and should last 10 to 12 years. Many of Loane Brothers' residential customers hire a crew to install the awnings every spring, then remove them in the fall, he says.

While some awnings can be rolled up either by hand or by an electric motor, they do block views. How far down the window an awning comes is called "the drop." An east-facing window needs a drop of 65 percent to 75 percent of the window height to do its job well. A south-facing window needs a drop of 45 percent to 60 percent to produce the same amount of shade.

New awning owners would be wise, I was told, to see if their homeowners' association or municipal government has rules restricting awnings or dictating what colors are acceptable.

2. Cover the windows

Although covering the interior of windows is not as effective as exterior shading at blocking the sun, it still is worthwhile.

One of the most efficient, if not gorgeous, window coverings is a heavy drape or curtain. "The tighter the curtain is against the wall around the window, the better it will prevent heat gain," reads a passage in "Cooling Your Home Naturally."

Venetian blinds also block the hot rays of the sun. They can be adjusted to let some light in while reflecting the sun's heat.

I have found a variety of shades on the Web, including some from the Washington-based Next Day Blinds. The store carries honeycomb cellular shades, which provide privacy and have energy-saving properties as well. Another type of window covering, called an Essential Double Cell, blocks 65 percent of heat transfer. A 36-by-60-inch shade starts at $75, plus shipping.

3. Ventilate

"Houses should breathe," says the Web site, and adds that "some experts recommend that one half of a home's air volume should be exchanged every hour."

To get these zephyrs moving, you should open windows at the lowest and highest points of the house and keep interior doors open. This is known as "thermosiphoning." It makes use of the principle that hot air rises, pushed up by cooler air.

There are a couple of caveats to natural ventilation. This technique works best during the coolest parts of the day and night. During the hottest part of the day, the thing to do, according to the DOE, is to seal off your house from the sun. Moreover, when the humidity becomes excessive, opening windows and doors does not bring much comfort.

If you don't have window screens, you can purchase small expandable screens that fit in a window sill. Units that are 10 inches high and expand to 24 inches wide cost about $9. Units that are 42 inches tall and can stretch up to 60 inches wide cost about $18. They are sold at most hardware stores.

4. Turn on a fan

Back when President Jimmy Carter urged us to save energy by turning office air-conditioner thermostats up to 78 degrees, government comfort gurus stated that we could tolerate a warmer room as long as the air inside it kept moving. In other words, if you turn on a fan, you might not have to turn on the air conditioner.

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