Late spring is the time you'll most commonly find dehumidifiers turned on for the season in damp and moldy basements.
In areas where there are a lot of old houses and a lot of humidity, "dehumidifiers are very popular," says home inspector Alan Beal, president of mid-Atlantic Inspection Services. Homeowners keep them humming until muggy season ends in October, preventing basements from smelling musty and repelling mildew and even cockroaches, moths and other bugs. Some find it helpful with allergy or asthma symptoms.
A dehumidifier's job is to take excessive moisture out of the air and dry it out. "The most comfortable range is 40 to 50 percent," says J.J. Klinkert, a Sears buyer.
You have a choice of what to do with the water that is collected: Connect a hose to a drain for continuous operation, or empty a collection bucket once or twice a day. Some units have auxiliary pumps. Dehumidifiers are also used in damp rooms with expensive home theater or music equipment, where a lower moisture level is preferred.
Bacteria repellent. Antimicrobial coatings on certain models inhibit growth of odor-causing bacteria.
Restart feature. If the power goes out, some units will restart on their own. Good for weekend houses.
Indicator lights. Most electronic units now have "bucket full" lights.
Convenience. Water-collection buckets have handles and splash guards for easier emptying.
Keep air moving. Place the dehumidifier at least six or eight inches away from walls for good air circulation.
Monitor temperatures. Most dehumidifiers operate less efficiently when temperatures fall below 65 degrees.
Check filters. Wash air filters once a month to help the fan operate efficiently.
Out-of-season care. Unplug and store units upright when not in use.
Low, middle, high
J.J. Klinkert, a buyer of home environment products for Sears and Kmart, suggests these dehumidifier models:
Frigidaire 30 pint: Caster wheels and handles on top and sides provide portability. Washable filter keeps air smelling fresh. Fold-down handle on bucket allows for easy emptying. Model FAD301NUD, $149 at Kmart.
Kenmore 50 pint: A timer lets you turn the unit on and off throughout the day. The bucket is coated with Microban to inhibit odor and bacteria. Automatic shut-off prevents bucket overflow. Model 50501, $199 at Sears.
Kenmore Elite 70 pint: Auto restart if power goes out. Remote control reports temperature and humidity or if bucket is full. Built-in pump means you never have to empty the bucket and allows you to pump water vertically. Model 90701, $299 at Sears.
When you're at a store, look for a dehumidifier with wheels for easier use, and test the store model to see how loud it is when operating. Here are a few more shopping tips:
1. Dehumidifiers are labeled with the number of pints of moisture they can remove in a 24-hour period, usually 25 to 75.
2. Consider the size of the bucket if you plan to remove collected water this way. Larger buckets mean you have to empty less frequently, but they are heavier and harder to lift. Most buckets hold between 10 and 20 pints.
3. If you drain to a floor drain or out a window, buy an appropriate hose. Most units don't come with one.
By the numbers
8: Average life span of a dehumidifier in years.
25-75: Range of capacity in pints of water that a home dehumidifier can remove in 24 hours.
$220: Average amount you can save over the life of a dehumidifier by buying an Energy Star model.
Sources: National Association of Home Builders; industry sources; Environmental Protection Agency.