An illustration of a dehumidifier.

It’s not the heat, as the adage goes, it’s the humidity.

Indoors, humidity can be a huge problem—particularly in basements, laundry rooms, bathrooms, and crawl spaces—any time there’s a string of warm, rainy days.

Telltale signs of too-humid air include musty odors, clammy conditions, condensation on windows, and damp spots on the walls or ceiling. Dampness can cause mold and mildew to grow and spread on your walls and ceilings, and that dampness can weaken wood.

A dehumidifier pulls moisture from the air, collecting the water in a removable tank. But not all are up to the task.

MORE ON YOUR HOME'S ENVIRONMENT

In our current dehumidifier ratings, you’ll see more than 20 models from Danby, Frigidaire, GE, Hisense, HomeLabs, Honeywell, and Midea. Most earn an Excellent rating in our water removal test, meaning they remove the number of pints of water from the air as claimed by the manufacturers.

But our tests also found differences among the models. For example, a dehumidifier that earns an Excellent rating in our humidistat accuracy tests comes close to holding the humidity level you select for your space. Only a handful in our ratings ace this test. 

Putting Your Dehumidifier to Work

Here’s expert advice, from CR and Energy Star, on getting the most from your dehumidifier.

Set the humidity level. The optimal relative humidity level is between 30 and 50 percent, according to Energy Star (and 30 to 40 percent in colder areas during heating season). If the humidity is higher than that, it can breed dust mites, mildew, and mold, and trigger allergies.

Pick the right spot. Be sure to allow enough room for air to freely flow into and out of the dehumidifier. Most of the models in our ratings release air through the top, but a few vent out the side. Regardless, they should have free space all around the dehumidifier. Your owner’s manual will have specifics for your model.

Close all windows and doors. Enclosing your space allows the dehumidifier to work more efficiently.

Empty the tank regularly. When the tank is full, an indicator lights up and the dehumidifier shuts off. To keep the dehumidifier running when you’re out of the house, empty the tank regularly in high season. Or you can connect a hose to any of the tested dehumidifiers to divert the water to a drain nearby. Some dehumidifiers have a built-in pump that pushes water horizontally or vertically through the hose and into a sink or even outside (through a basement window, for example). There aren't any pump models in our current dehumidifier ratings, but we'll be testing more models soon.

Keep it clean. The filter cleans the air that flows through the dehumidifier, and when it’s dirty, your dehumidifier’s efficiency takes a hit. Many models in our ratings have an indicator light to tell you when it is time to clean the filter. Wash and dry it regularly, following your manual’s advice. While you’re at it, see the manual’s advice on cleaning the grill. When the grill is dirty, air movement is slowed.

3 Top Dehumidifiers From CR's Tests

Ready to get one up and running? These models offer impressive performance.

Quick Take

Honeywell TP70WKN

Price: $300

Water removal
Humidistat accuracy
Unlock Dehumidifier Ratings
Quick Take

hOmeLabs HME020006N

Price: $230

Water removal
Humidistat accuracy
Unlock Dehumidifier Ratings
Quick Take

Honeywell TP30WKN

Price: $200

Water removal
Humidistat accuracy
Unlock Dehumidifier Ratings

Other Ways to Deal With Dampness

Even the best dehumidifiers can’t make up for the problems that create damp air in your home. Here’s your moisture-control checklist, for potential sources inside and outside the house:

Run the exhaust fan. When you’re cooking or right before you shower, turn on the range hood or exhaust fan to remove moisture from the space. No fan? Open a window.

Clean your dryer duct. A clean duct vents the warm exhaust air to the outside. And clearing the duct of lint maintains airflow, allowing your laundry to dry faster, and helps prevent dryer fires

Check plumbing for leaks. Check plumbing that you can access (in your basement, under sinks, at the outside spigot) for leaks or condensation.

Clear gutters. Direct rainwater away from your house by preventing any clogs in your gutters, and extend downspouts so that the water flows away from your foundation.

Inspect your foundation. Water can seep into even the smallest cracks. Use silicone caulk or hydraulic cement to seal cracks that are ¼ inch or less in width. If you spot larger cracks, consult a structural engineer because they could indicate a structural problem.

Check gradation of the soil. It should slope away from your home’s foundation to prevent water from pooling. And don’t go crazy with the water when you’re watering plants near the foundation.