We test dehumidifiers in three categories based on capacity, which refers to the amount of water they remove from the air:

Small: rated to remove 30 to 35 pints of moisture per day

Medium: rated to remove 50 pints per day

Large: rated to remove 60 to 70 pints per day

Our water-removal tests measure a model’s ability to remove water from the air in our test chamber at 80° F and 60 percent relative humidity. The humidistat accuracy test determines how closely each dehumidifier can reach and maintain a set humidity level.

For energy efficiency, our engineers calculate the amount of energy it takes to remove one pint of water from the air, and our cool room performance test judges a model’s water removal and efficiency performance in a room at 50 degrees and 60 percent relative humidity (a good indicator of performance in a cold, wet basement).

All this data is compiled into an Overall Score and ratings for every dehumidifier we test. Our complete dehumidifier ratings cover about 30 models.

Consider Where It Will Go
Noise is a concern in living spaces. Our measurements from 3 feet away typically range from about 55 decibels (approximately the sound of loud conversation) to 67 decibels (the din of street traffic) for the dehumidifiers we test.

New Energy Standards
Because of new federal energy standards, many dehumidifiers in our latest tests earn a Very Good rating or better for energy efficiency. That means you’ll see savings in operating costs compared with older dehumidifiers. That’s important because during hot and humid weather, a dehumidifier is running around the clock.

Large or Wet Spaces
The best large-capacity models remove moisture quickly and efficiently in the toughest situations, such as an especially wet basement.

Small or Damp Spots
A large-capacity dehumidifier will help dry a smaller space quickly, but a medium-capacity model will probably do it with less cycling on and off, according to manufacturers.

Time Your Purchase
New models appear in late spring and early summer, and most sales and in-store promotions occur from June through August. You might find closeout deals in the fall and early winter.

Fix Existing Problems


Even the best dehumidifier might not work effectively if too much outside moisture seeps into your home. Unclogging gutters and checking that downspouts are directing rainwater at least 5 feet from the house can help.