Costly air conditioning © Brian Hagiwara/Corbis

The Basics

Keep cool without pricey AC

Whole-house fans and evaporative coolers can take the edge off summer's heat for just pennies an hour. But they're not for everyone or every climate.

By Marilyn Lewis

You might think your only options for a heat wave are air conditioning, fans or sweating it out. But a couple of old-school technologies could keep you cooler and cut your electricity bills at the same time.

There's always a catch, though, isn't there? These alternatives -- whole-house fans and evaporative coolers -- don't perform well in all climates. If your area is humid, you won't be able to use most evaporative coolers. If your skies stay warm at night or if you don't have an attic, don't try a whole-house fan.

But if nights are cool and you've got a hot attic, or if your air isn't already dripping with moisture, read on. You could save a bundle.

Not long ago, fans and evaporative coolers -- known with derisive affection as "swamp coolers" -- made homes livable in the hottest climates. "In the '60s, an evaporative cooler was all we had," recalls Arizona native John Kirby, an engineer with SRP, a Phoenix-area utility. "Most homes couldn't afford air conditioning until it got more reasonable."

But there were downsides, including noise and, with swamp coolers, lots of maintenance. Enter central air conditioning: Invisible and quiet, it became the high-status choice. In the U.S., 89% of homes built in 2006 had central air, says the National Association of Home Builders, compared with just 46% in 1976.

But air conditioners draw lots of power, so now, with both summer temperatures and electricity costs rising, these old energy misers deserve a second look with newer, quieter models that need less maintenance.

Evaporative coolers

These also are called "poor people's air conditioning" because they're so cheap to run. But what's wrong with that? They use up to 75% less energy than air conditioners, says Gerald Katz, an energy specialist with Colton (Calif.) Electric Utility.

Because they don't cool as effectively as air conditioning, in really hot climates their use is limited to late spring and early fall.

There are several types:

  • Rolling. These budget coolers cost about $300, and run for as little as pennies an hour, depending on local electric rates. They are particularly effective in apartments and condos, where rooms are smaller and rules might prohibit anything in the windows.
  • Window. Old coolers were big, noisy metal boxes that covered a window. Many new ones use high-quality plastic and sit outside, beneath a window, with an outlet through the window into the home. They cost about $400 and up, installed, and less than 10 cents an hour to operate. They must be flushed and cleaned regularly to prevent rust and calcium buildup. Newer models need only yearly maintenance.

  • Roof-mounted. These high-end, low-maintenance coolers are installed on roofs and connected to ducts that direct cool air into the house and force hot air up and out. Some are built right into attics. They cost $1,000 and up, installed, and up to 20 cents an hour to run. But compare that with $5,000 to $6,000 for new central air that costs 75 cents to $1 an hour to run.

Save more money

Katz's municipally owned utility gives small evaporative coolers to some low-income customers. "I've seen bills drop by $100 a month when we give people these," he says.

His job includes helping customers conserve electricity -- and money. "I see people paying $150 a month for electricity in apartments and $200 to $300 or more in homes," he says. In summer, electricity use typically doubles, which tells him that air conditioning accounts for about half the bill.

Video on MSN Money

Heat wave © David Gould / Photographer
The heat is on
You can count on your power bills to rise alongside summer's temperatures.

Evaporative coolers work by pulling fresh air over pads soaked in cold water. The air is chilled, cleansed and sent into the house on a cool breeze. You must open windows or doors while it's running so hot air can escape. If that's unsafe, consider an UpDuct, a pressure-operated damper ($12 to $15 where you buy evaporative coolers) installed in outside walls.

Continued: Making the decision

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