When indoor humidity levels are high, moisture can damage the structure, surfaces and condition of the home or increase the amount of allergens and pollutants in the air, affecting your health. We'll explore dehumidifier benefits and features to ensure you select the best one for your home.

What Does a Dehumidifier Do?

There are several warning signs that may indicate your home needs a dehumidifier. These include foggy windows and the sensation of sweaty skin. A heavy, wet atmosphere in your home or the detection of a musty smell are also warning signs.

Even if you have home air conditioning, a dehumidifier may still be necessary. Running dehumidifiers in basements or using a bathroom dehumidifier is a good idea because air conditioning alone may not be enough to remove the dampness in these spaces. Dampness also leads to mold, which can result in allergy issues and respiratory illnesses. While there's not a specific dehumidifier for mold, it will remove the dampness in the air that prevents mold spores from forming in the first place.
A dehumidifier helps maintain an ideal relative humidity (RH) level in the home. During the summer months, a 50% RH is recommended. In the winter months, it’s acceptable to stay as low as 30% RH, especially if you have condensation on the windows.

How Do Dehumidifiers Work?

Dehumidifiers work by forcing air with a fan over coolant-filled coils to remove moisture. Depending on the model you use, the moisture will either drip from the coils into a basin or be pumped out of the unit. Drier air is then expelled back into the room.

Selecting the Best Dehumidifier

There are several factors you should consider when selecting your dehumidifier:

• The square-foot dimensions of the area you wish to dehumidify
• The method you wish to use to remove the water collected by the dehumidifier (bucket/basin or pump)
• The energy performance of the unit

The dehumidifiers you use in a small bedroom will be different than the dehumidifier for basement usage. Dehumidifiers vary according to pint-removal capacity every 24 hours. The following guide will help you choose the right capacity model for your needs. The numbers listed are in pints per 24 hours.

Knowing the type of dehumidifier you need will also help you make informed purchasing decisions. There are several types of dehumidifiers available.

Compressor Dehumidifiers

A compressor dehumidifier (also referred to as a refrigerant dehumidifier) takes air in from a room or area. This cold air passes through a filter then through internal evaporator coils. When the air reaches the coils, the water condenses and drips into the internal tank, removing the moisture from the air.

Compressor dehumidifiers are best suited for warmer climates and areas where there are high levels of humidity because they won’t collect moisture at temperatures below 59 degrees Fahrenheit.

How to Use a Dehumidifier

Follow the setup instructions in your owner’s manual. When unpacking the unit and removing the shipping tape, make sure to keep the bucket in place. Check the internal bucket to ensure the float switch isn’t dislodged (refer to the instruction manual). When first using your dehumidifier, set the RH level to the driest (highest) setting possible to stabilize the room’s humidity. After a couple of cycles, set the unit’s automatic humidistat to the setting you prefer. Most units have RH settings as low as 30% and as high as 90%.

Also remember:

• Maintain unrestricted airflow. Units with vents on top may sit flush against a wall. Units with vents on the back and sides require 6 inches of circulation space from walls and furniture.
• Keep the air filter clean by checking it regularly. A dirty filter restricts airflow and affects the unit’s performance.
• Plug the dehumidifier into an appropriate ground fault circuit interrupter (GFCI) outlet. Never remove the third prong from any plug.

Dehumidifier Features

Depending on the unit, your dehumidifier may have a(n):

• Internal Pump: automatically pumps water vertically to a water basin for continuous operation
• Direct Drain: feeds to a floor-level drain, which allows for continuous operation
• Filter Indicator: shows when the air filter needs to be cleaned
• Auto-Humidistat: senses the moisture level in the area around the unit and automatically shuts off the unit once the desired humidity level is reached
• Low-Temperature Setting: allows units to operate in temperatures as low as 41 degrees Fahrenheit
• Auto-Defrost: keeps units from freezing in environments below 65 degrees Fahrenheit
• Auto-Reset: restarts the unit to its previous setting in case of a power loss

Drain Options

In very damp or wet conditions, the unit will collect a large amount of water, so you’ll need to empty the internal bucket regularly. Most units have a direct-drain feature, which allows for continuous operation without emptying the unit’s bucket, but it requires a floor-level water drain. If you don’t have access to a floor-level drain and want to avoid regularly emptying an internal bucket, buy a unit with an internal-pump feature that can pump water vertically up to a sink.

Dehumidifier Energy Performance

Energy performance is rated by the amount of water extracted every hour versus the amount of energy consumed to do so. For maximum efficiency, look for an ENERGY STAR® certified unit.

Dehumidifier Maintenance Tips

Dehumidifiers vary by size and brand. Below are general tips to care for and maintain your dehumidifier:

• Always unplug the unit prior to inspection and cleaning.
• Clean the dehumidifier regularly. Look for dust or mold buildup in the inlet cover.
• Check the dehumidifier’s filter at least once a month and clean or change as necessary.
• Vacuum the air intake grills.
• Check the drain hole for clogs and clean or replace as necessary.
• For units that aren't self-draining, empty and clean the water collection bucket at least once weekly in hot, soapy water or 3% hydrogen peroxide to prevent mold, limescale, etc. from building up in the bucket.
• Check the coils regularly to prevent them from freezing.
• Vacuum any other internal parts as needed.