How to Choose a Dehumidifier That’s Right for Your Home

A dehumidifier can help prevent excess moisture in the air from turning into a mold and mildew problem. Read on to learn how to select the best possible unit, and what size dehumidifier you need for your space.

By Timothy Dale and Donna Boyle Schwartz | Updated Aug 4, 2021 5:14 PM

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how to choose a dehumidifier

Air quality can suffer in myriad ways. Excess humidity ranks among the least desirable effects. Left unchecked, moisture buildup can lead to several problems within the home including, but not limited to, musty odors, warped wood, peeling paint, and mold.

If at any point during the year you become concerned about the high humidity level inside, what can you do to alter the status quo? One word: dehumidifier. Continue reading to learn how to choose a dehumidifier for your home.

Water Damage, Mold, and Your Health

Dehumidifiers help reduce excess moisture and water damage within the home, which makes it easier to breathe. Dehumidifying also helps stop mold, mildew, and even dust mites from spreading throughout the home. This is an important preventive measure, given that mold is drawn to many common building materials, like ceiling tiles, wood, and wood products.

According to the CDC, exposure to damp, moldy environments can cause a variety of health problems that range from mild symptoms, like a stuffy nose or wheezing, to more serious symptoms such as fever, shortness of breath, and the development of asthma in children.

How Dehumidifiers Free a Space of Moisture

Dehumidifiers range in size from portable, one-room units to whole-house solutions that tie into the home’s HVAC system. Though variations exist both in product design and quality, most dehumidifiers work the same way. You configure the preferred humidity level, and when the humidistat registers a level that exceeds your preference, the dehumidifier clicks on.

Driven by a fan, moist air moves through the appliance, where it passes over a cold metal coil. At that point, the moisture condenses into water, which the unit stores internally or drains away. The filtered air then passes over a warm coil before returning to the home’s conditioned space. The owner just needs to regularly empty any collected water.

How to Choose the Right Dehumidifier for Your Home

Before jumping to invest in the first dehumidifier that you see, it’s necessary to pay attention to key factors about the product and your home to figure out what size dehumidifier you need, along with the type and efficiency level that would be most appropriate to reduce the humidity.

how to choose a dehumidifier

Test for excess moisture.

There are several signs of high humidity in a home that can help you determine whether you need a dehumidifier. Inspect the windows and doors for fogging or excess condensation and note whether any moisture is accumulating on the walls or ceilings.

If you see some of these signs but aren’t certain whether your home has been experiencing significant moisture issues, research the problem by purchasing and monitoring a humidity gauge, also known as a hygrometer. This device monitors the indoor air quality and reports the readings.

For most homes, a humidity level of between 30 and 60 percent shouldn’t cause issues, but narrowing the range to about 30 to 50 percent will help ensure that the air is easy to breathe and the home is comfortable. Humidity levels higher than this ideal range should be treated with a dehumidifier.

Determine the scope of the problem.

Is the entire house overly humid, or is the issue confined to one area (such as the basement)? The scope of the problem directly determines the nature of the solution. Larger whole-house dehumidifiers tie into the HVAC system and include a drainpipe that empties directly into a slop sink, sump pump, or to the outdoors. These types of dehumidifiers aren’t cheap and typically involve professional installation.

Portable dehumidifiers, meanwhile, are much less expensive and much more consumer-friendly. They plug right into the wall and operate via built-in interfaces that are easy to understand and configure. Some portable dehumidifiers are equipped with hoses that can drain or pump out collected water automatically; others feature a collection bucket that must be emptied on a regular basis.

What size dehumidifier do I need?

Even dehumidifiers of the same basic design can differ in capacity. Select a small one that can hold 10 pints of water for a 500-square-foot space; add 4 pints of capacity for every additional 500 square feet. So, to determine the size of humidifier for a 1,000-square-foot basement, you’d need to add 4 pints for a total 14-pint capacity.

For a very damp basement or other space, it might be necessary to increase the size of the dehumidifier to efficiently remove the increased level of moisture from the air. Choose a dehumidifier that holds 12 pints of water for a 500-square-foot space, adding 5 pints for every additional 500 square feet.

Consider these additional factors before selecting a dehumidifier for your space.

The square footage of the home or of the room where you will set up the dehumidifier is the main deciding factor for choosing a product, but there are other household conditions that can affect the humidity level in the home and what size humidifier you need.

People consume water, sweat, and breathe out hot, humid air, so the more people in the home, the higher the humidity will be. In most homes, the humidity produced by humans is negligible, but large families of six or more people might want to consider a larger dehumidifier to handle increased humidity levels.

The size and number of doors and windows in the home can also influence the humidity levels in the home. Windows and doors allow heat to transfer more easily into the home, so the more windows and doors, the higher the humidity. Similarly, very large windows are poor insulators, leading to higher levels of humidity.

Laundry rooms and bathrooms can affect a home’s humidity level when you use the washing machine or shower, so it’s important to invest in a dehumidifier that can handle the increased moisture in the air. In summary, when determining what size dehumidifier is right for you consider the size of the room or home, plus:

  • The number of occupants in the home
  • Size and number of doors and windows
  • Laundry room and bathroom usage

Prioritize energy efficiency.

Energy Star-rated dehumidifiers use about 15 percent less energy than conventional units. In the long run, that means a savings of approximately $175 over the life of a dehumidifier, not to mention avoiding roughly 2,800 pounds’ worth of greenhouse gas emissions.

Dehumidifiers can provide a continuous flow of fresh, dry air in the home, resulting in an energy-efficient solution that improves indoor air quality and keeps mold growth at bay all season long.


What Size Dehumidifier Do I Need -- how to choose a dehumidifier

The Advantages and Disadvantages of Dehumidifiers

There are many reasons why running a dehumidifier in the home is a good idea. The units can reduce allergy symptoms and other health issues by stopping the spread of mold, mildew, and dust mites in the home. These devices also help to reduce the ambient moisture in the air, protecting the home from rust and decay that can occur when walls, ceilings, and windows accumulate moisture.

There are also disadvantages to having a dehumidifier, one of which is a higher monthly electricity bill. They also require regular maintenance to ensure that they continue to function correctly. Maintenance includes emptying the collection bucket, cleaning the unit, and replacing the air filter to help purify the air.

The ongoing hum of the dehumidifier, especially on higher operating levels, can also be a nuisance to some people, so it’s important to research how loud a dehumidifier is—and whether you actually need one—before bringing one home.


  • Help reduce allergy symptoms
  • Stop mold, mildew, and dust mites from spawning
  • Protect the home from premature rust and decay


  • Increased electricity consumption
  • Ongoing maintenance requirements
  • Constant background noise

FAQs About How to Choose a Dehumidifier

What Size Dehumidifier Do I Need -- how to choose a dehumidifier

Q. Can a dehumidifier be too big?

Most dehumidifiers have a built-in humidistat to measure the ambient humidity, so while an oversize dehumidifier can cause the air in the home to dry out quickly, it should shut off when the humidity levels reach the preferred setting.

However, without this automatic measurement and control, a dehumidifier can be too large for the space. It can dry out the air rapidly to the point where it is too dry and you might need a humidifier to help reverse the effects.

Q. Can one dehumidifier do a whole house?

A whole-house dehumidifier is intended for this exact purpose. These products can have a range that exceeds 5,000 square feet, allowing them to condition the air throughout the home.

Q. Should you leave a dehumidifier on all the time?

No, do not leave the dehumidifier on all the time. Not only is it unnecessary, but excessively dry air can lead to breathing problems, like bronchitis, sinusitis, asthma, and nosebleeds.

Q. How often should I empty my dehumidifier?

The frequency with which you empty the dehumidifier depends on how often the device runs. Typically, a dehumidifier should be emptied twice a day, but some homes might only need to empty the bucket once every 2 days or so. Just be diligent about checking the dehumidifier when it is first set up to get a better understanding of how long it takes for the dehumidifier bucket to fill up.