A good dehumidifier is like a little insurance policy for your comfort and health. A dehumidifier can also make your home more pleasant by helping it feel less damp and smell less musty indoors.
With its drying power, a dehumidifier can bring indoor relative humidity to below 50 percent—the point at which dust mites, mildew, and mold can grow. That drier air can also help keep allergies and other health problems at bay.
And in the event you have a wet basement or leak in the roof, a dehumidifier can help make your home livable again.
A dehumidifier uses a fan to move air in the room over refrigerated coils, removing moisture and collecting it in a tank. Dehumidifier makers all claim their units remove a given number of pints of water from the air, but our tests show significant variability in their success at that task. (For more on this, see “Changes in Dehumidifier Test Standards,” below.) We also found that some of the models we tested come much closer than others to meeting the selected humidity level. Some use less energy, and some have a larger tank, meaning you won’t have to empty it as often.
How We Test Dehumidifiers
We test dehumidifiers in three categories based on their capacity, which is the claimed measurement of the amount of water each model can remove from the air. Here’s how we categorize the models in our current dehumidifier ratings.
• Small: Claimed to remove less than 30 pints of moisture per day.
• Medium: Claimed to remove 30 pints to less than 40 pints per day.
• Large: Claimed to remove 40 or more pints per day.
Our water-removal tests measure a dehumidifier’s ability to remove moisture from the air (the number of pints of water per day, as claimed by the manufacturer) in our test chamber set at 65° 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 1 pint of water from the air. For our convenience rating, we evaluate how often you’ll have to empty the tank. We also measure and judge noise levels.
These lab-test results, along with brand reliability and owner satisfaction data from our CR member survey, are incorporated into an Overall Score for each dehumidifier.
Changes in Dehumidifier Test Standards
Labels and packaging of dehumidifiers sold since the beginning of 2020 typically claim the units can remove 20, 30, or 45 pints in 24 hours. That’s a change from the packaging of earlier dehumidifiers, which claimed removal rates of 30, 50, or 70 pints per day.
The lower figures don’t mean these new models remove less water, though. Rather, in accordance with new, more realistic government standards that went into effect in 2019, they were tested by the manufacturer in a condition where less moisture needs to be removed.
Dehumidifiers are typically used in basements, and the Department of Energy changed its test standard by lowering the room temperature by 15° F to 65° F, to better reflect basement conditions. There’s less water to remove in cooler air, which is why the number of pints of water drops. The relative humidity level in both the old and new test is 60 percent. CR uses the new standard in its tests as well.
What to Know Before You Shop
Fix Existing Problems
Even the best dehumidifier might not work effectively if too much outside moisture seeps into your home. Unclogging gutters and making sure downspouts are directing rainwater at least 5 feet from the house can help. For more tips, check out “How to Get the Most From Your Dehumidifier.”
Consider Where It Will Go
Noise can be a concern in living spaces. Our noise measurements taken from 3 feet away range from 58 decibels to 67 decibels for the dehumidifiers in our current ratings.
Normal conversation is around 60 decibels, and a clothes washer is about 70 decibels, according to the Centers for Disease Control and Prevention.
Focus on Models Meeting the 2019 Standard
The more realistic claims should be closer to the dehumidifier’s true performance in your basement, says Misha Kollontai, who oversees CR’s dehumidifier testing. If you can’t find mention of the 2019 standard on the packaging or product information guide, check the model page on the manufacturer’s website. The retailer’s page may also display the information in the product details.
Match the Machine to the Moisture
Dehumidifiers vary in the amount of moisture they can remove in 24 hours. Here are the types to consider.
Large-Capacity Dehumidifiers
The tested models are claimed to remove 40 or more pints per day. They can also handle a wider range of humidity levels with little or no additional noise. You may also be able to run them on a lower, quieter setting. For large, wet spaces, buy the largest capacity model you can afford. The extra cost is worth it.
Medium-Capacity Dehumidifiers
For midsized or large spaces that aren’t quite as damp, these models typically are claimed to remove 30 pints to less than 40 pints of moisture per day. Though medium-capacity dehumidifiers can sometimes cost as much as large models, you’ll usually pay less.
Small-Capacity Dehumidifiers
Claimed to remove less than 30 pints of moisture per day, these can dehumidify small spaces that are damp rather than wet.
Whole-House Dehumidifiers
Whole-house dehumidifiers are available as portable units or as add-ons to your existing central heating and air-conditioning system. Manufacturers say they can handle an area up to 5,000 square feet. These units are expensive, but the large amount of moisture they remove allows you to cut back on air conditioning. (CR doesn’t test this type of dehumidifier.)
Features That Count
Most portable dehumidifiers now come similarly equipped. Here are the features you’ll typically see.
User-Friendly Controls
Electronic controls let you select a basic humidity level—normal, dry, very dry—and digital controls let you program a specific humidity level with percentage numbers.
Auto Restart
Found on most tested models, it turns the dehumidifier back on after a power outage—handy if there’s a blackout while you’re away from home.
Hose Connection
All the tested dehumidifiers allow you to connect a hose to the dehumidifier. This allows you to divert the condensed water directly to a floor drain so that you don’t have to empty the bucket. In a basement without a floor drain, a dehumidifier with a pump can send water up through a window, to a slop sink, or to some other high drain.
Timer
A timer can program the unit to turn on and off while you’re out of the house. It also can save money by turning the dehumidifier on at night in areas that have cheaper off-peak electricity rates.
Frost Control Sensor
Most of the dehumidifiers in our ratings have a sensor that turns off the dehumidifier if frost forms on the coils—common in cooler spaces. That keeps the unit from wasting energy by running without dehumidifying.
Easy-to-Empty Bucket or Tank
It should have comfortable handles and a cover that permits convenient removal and carrying when it’s full.
Dehumidifier Brands
Here are some of the more popular brands.