Does a Dehumidifier Really Help Your Air Conditioner?

How Dehumidifiers Work

• Dehumidifiers function in a manner similar to that of air conditioners. They take in hot air from the house and pass it over cold coils, which "sweat" the humidity from the air, just as a cold glass of water sweats when placed in a hot room. The sweat, or condensate, drips into a pan, and the dehumidified air passes over warm coils, which raise the temperature of the air and disperse it back in to the room.

How Air Conditioners Work

• Air conditioners work in a manner similar to a dehumidifier but add in a mechanism to dispose of heat from the air. A dehumidifier is not vented to the outside, so it cannot disperse indoor hot air outside the home. Air conditioners have external condensers, which allow them to dump hot air outside. The chief purpose of an air conditioner is to reduce the indoor air temperature, dehumidifying air as a byproduct.

How a Dehumidifier Can Help Air Conditioning

• In especially humid parts of the house, such as damp basements and laundry rooms, a dehumidifier can assist the air conditioner. When air is humid it feels muggy, or uncomfortable. In a humid room, a user may feel compelled to lower the thermostat on the air conditioner to a temperature considerably lower than he would if the air were dryer. In this way, the heat generated by a dehumidifier can be offset by the reduced power usage for the air conditioner in more humid areas.

How a Dehumidifier Hinders an Air Conditioner

• Dehumidifiers are basically small air conditioners. They have a lot of electrical components and motors that not only use electricity but also generate waste heat. As such, a dehumidifier is something of a small heater and can work against an air conditioner. In rooms that are not especially humid, it may not be cost effective to run a separate dehumidifier while an air conditioner is in use.