How Do I Know What Size Dehumidifier I Need?

If you have an area of 600 to 800 square feet that’s slightly damp or infused with a musty smell, a medium-capacity dehumidifier may solve your problem.

Wetter rooms as small as 400 square feet can also benefit from midsized units, which are designed to remove 30 to 39 pints of moisture per day. 

As a group, medium-capacity dehumidifiers are quieter than larger models, which is useful when you’re trying to dry out the air in a living area. You’ll typically pay somewhat less for a medium-sized dehumidifier, but some can cost as much as a large model.

Pro tip: Medium-sized rooms (between 600 and 1,200 square feet) with small puddles, visible condensation, or mold need the same attention as larger spaces. That means using a large-capacity dehumidifier, Kollontai says.

To see if your dehumidifier is up to the task, check the room’s humidity level with your hygrometer, set up the dehumidifier and run it for a while, then check the humidity level once again, Kollontai says. On many dehumidifiers, you can see the relative humidity level in the unit’s built-in digital display. But it’s also a good idea to use that hygrometer you bought to take readings in different areas of the room to make sure the humidity is evenly distributed.

“If, at full power, your dehumidifier is only pulling your humidity down to 60 or 70 percent, you need a bigger dehumidifier,” Kollontai says.