Tips for Choosing a Dehumidifier

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Too much air moisture in a home can lead to a variety of problems, including moisture damage to building materials and mold. This problem can be more pronounced if you leave in a climate where high humidity is a constant, or in a region that has very moist seasons at certain times of the year. The solution to this problem is to buy and run one or more dehumidifiers in your home when and where high humidity is an issue. 

Mechanically, dehumidifiers work by creating condensation. They pull warm, moist air into the unit and chill it against coils containing a liquid coolant. The moisture that condenses out of the air is captured, and the dry air is sent back out into the room. If you are planning to use your basement for storage or living space, a dehumidifier can prevent moisture damage and provide greater comfort.

Here are some basic considerations to keep in mind before you start ​shopping for a dehumidifier:​

Room Size

Dehumidifiers tend to be rated according to how many pints of water they can remove from the air per day and how many square feet they can keep dry. The former is the most useful indicator of performance, but most consumers rave no idea how much moisture needs to be removed. Fortunately, knowing the square footage of the room (length times width) can provide a close estimate of what you need. Err on the side of overcapacity: if the square footage of your basement is near the top end of a dehumidifier’s promised capacity, get the next larger size.

Level of Humidity

If you live in a humid climate, or if your basement has a particularly high level of moisture, a standard dehumidifier may not be able to function adequately. Instead, look for a high-capacity unit built to operate more often than normal.

Room Temperature

Most dehumidifiers operate best at normal room temperatures. If your basement is usually on the cold side, a standard dehumidifier may not function well and could suffer premature damage. Instead, look for a unit that can handle cold temperatures.


Some dehumidifiers are noisier than others. Try to operate a unit before you buy it to see if the noise level is acceptable or not.

Energy Consumption

You can keep your energy costs to a minimum by following these steps:

  • Buy a properly sized unit (slightly bigger than necessary is better than slightly smaller).
  • Buy the most energy-efficient unit you can afford (Energy Star-rated dehumidifiers are available).
  • Operate and maintain the unit as directed by the manufacturer.


A dehumidifier should be plugged into a grounded outlet and have at least 12 inches of air space around it when in use. Be prepared to check the water level in the tank several times a day at first to determine how quickly it fills up.

If you have a floor drain in your basement, you can avoid having to empty the tank by attaching a hose to the dehumidifier and running it to the drain.

Plan to clean the water tank at least once a month with a mild detergent. Always unplug the unit before working on it. Clean or replace the filter at least twice per year.