There are three common types of home dehumidifiers: heat pump dehumidifiers, chemical absorbent dehumidifiers and dehumidifying ventilators. Each has advantages.

Heat pump dehumidifiers extract water from the air by using a heat pump that is similar to an air-conditioner pump.

First a fan pulls the indoor air across a very cold coil, which causes the moisture to condense. The droplets drip in a bucket that fits inside the unit.

The dry air is warmed by a second, heated coil and exhausted at room temperature. These dehumidifiers are considered among the most effective for homeowners to use.

For more about this type of dehumidifier, see How a Dehumidifier Works.

Chemical absorbent dehumidifiers work best in warm climates. These dehumidifiers use a chemical drying agent, or desiccant, on a heat exchange wheel to absorb water molecules from the air.

Damp air is sent outside via vents. Desiccant dehumidifiers require a lot of energy to operate. These dehumidifiers are more commonly used by industries than homeowners.

Dehumidifying ventilators have a sensor controller and exhaust fan. The sensor controller activates the unit when humidity reaches a specified level.

Dehumidifying ventilators are less effective in muggy climates, because they draw outside air into the house. These dehumidifiers often are used in basements.

But they can depressurize a room and cause gas spillage. Make sure gas furnaces are properly vented.