What Is a Dehumidifier?

Dehumidifiers pull excess moisture from the air inside your home. Some moisture is preferred in interior environments (which is why you might run a humidifier during the winter), but too much humidity can cause a variety of problems. High humidity levels make spaces feel muggy, sticky, and uncomfortable, especially as temperatures rise. It also aggravates health issues like allergies and asthma. Plus, excessive levels of humidity can also lead to mildew and mold growth. A portable dehumidifier lets you maintain an ideal level of humidity in your home.

Do I Need a Dehumidifier?

Whole-house and window air conditioners remove some of the moisture from your home's air, but if you live in a particularly humid climate, you might need additional help. Major signs of excessive humidity in a home are: condensation on the inside of windows (especially double or triple-pane windows), dripping or "sweating" pipes, peeling wallpaper, warping wood floors, and difficulty opening wooden doors or windows in the summer. If you're dealing with any of these issues, you could benefit from running a dehumidifier.

How Dehumidifiers Work

While there are several types of dehumidifiers, we're going to focus on portable, refrigerant-style devices as they're the most common. These models use a fan to pull moist, warm air into the unit. Once inside, the moist air passes over refrigerant cooled coils.

As the air cools, it loses its ability to hold water and releases the moisture into the dehumidifier. This water drains out of the dehumidifier via a hose or collects in a holding tank that needs to be emptied manually. After shedding the excess water, the cooled air passes over a warming coil and gets released back into your room.

What Size Dehumidifier Do I Need?

Dehumidifiers are rated by the amount of water they remove from the air in a 24 hour period. The Association of Home Appliance Manufacturers (AHAM) uses the below chart to help homeowners determine what size dehumidifier will best meet their needs.

Condition of Space without Dehumidifier 500 Sq. Ft. 1,000 Sq. Ft. 1,500 Sq. Ft. 2,000 Sq. Ft. 2,500 Sq. Ft.

Moderately Damp Space with Musty Smell in Humid Weather 10 pints 14 pints 18 pints 22 pints 26 pints

Very Moist Space with Smells and Damp Stains on Walls and Floors 12 pints 17 pints 22 pints 27 pints 32 pints

Very Wey Space with Wet Walls and/or Seepage 14 pints 20 pints 26 pints 32 pints 38 pints

Extremely Wet with Wet Floors and High-Load Conditions 16 pints 23 pints 30 pints 37 pints 44 pints

Source: Association of Home Appliance Manufacturers (AHAM)

As you can see, the two most important factors in determining what size dehumidifier you need are the condition and size of your space in square feet. This chart provides a good sense of the smallest dehumidifier that will still be effective in a given room. It's also a good idea to add 5-10 pints of capacity for rooms with high ceilings and those capable of producing moisture, like bathrooms, laundry rooms, and kitchens.

However, there are a number of advantages to buying larger models for use anywhere. As noted above, the "size" of a dehumidifier is actually the rate at which it pulls water from the air. Using a larger dehumidifier than your space requires will dry the air more quickly. And while larger models use more energy while in running, they use less energy overall because they don't need to run as long to finish the job.

The faster your dehumidifier gets the job done, the less time you and your home will be subjected to the negative effects of moist air. Plus, dehumidifiers that spend less time actively pulling water from the air will enjoy a longer lifespan. Like any appliance, the more you use a dehumidifier, the more stress gets put on its internal parts. And while it will likely be several years before any of the parts fail, the efficiency of a large dehumidifier ensures the longest possible life.

Because of this, we recommend purchasing the largest dehumidifier you can afford. The higher upfront cost is offset by both energy savings and a machine that will outlast smaller models.

What to Look for in a Dehumidifier - Options and Features

In addition to the size of your dehumidifier, there are a number of features to consider when deciding which model is right for your space.

Air Filter

Many dehumidifiers include an air filter to contaminants from the air in addition to moisture. This improves the air quality of the space by removing allergens as well as mold and mildew from the air. Doing so helps eliminate the musty smell that's common in damp environments.

More importantly, it keeps dirt particles from entering the adversely affecting the unit's performance. Look for a dehumidifier with a washable air filter and remember to clean it on a regular basis.

Auto-Defrost

Frost can form inside a dehumidifier in temperatures below 65° F. An automatic defrost function turns the compressor off until the unit defrosts to prevent damage. If you plan on running your unit at lower temperatures, make sure to purchase one capable of auto-defrost.

Auto-Restart

In the event of a power outage, auto- restart turns the dehumidifier back on when the power returns. This feature is especially important for remote locations, like a lake house. Even if you aren't around for the power outage, you can rest assured that your dehumidifier will get to work again as soon as possible.

Caster Wheels

Caster wheels are typical on most dehumidifiers, and allow for easy transportation and portability.

Dehumidifier Collection Tank

Most dehumidifiers feature a collection tank that holds water pulled from the air. Once a dehumidifier extracts enough moisture to fill the tank, it has to be emptied manually. To prevent overflows, almost every dehumidifier includes an automatic shut-off that turns the unit off when the collection tank reaches capacity. Models with front-loading buckets are the easiest to empty.

As stated above, the "size" of a dehumidifier is actually a measure of the rate at which it pulls moisture from the air. It does not provide any information about the size of the collection tank. So, whether you have a 20 pint or a 70 pint dehumidifier, you may have to empty the collection tank a few times a day to make sure it continues to function. Alternatively, look for a model that offers direct drain-off.

Dehumidifier Continuous Drain

If manually emptying a collection tank sounds like too much of a hassle, look for models that offer continuous or direct draining. By connecting a hose to these models, water pulled from the air drips out continuously instead of collecting into a tank. This also lets the dehumidifier run without breaks and is a great feature for when you're away from the dehumidifier for long periods of time.

Although direct drain dehumidifiers are significantly more convenient than models that only feature a collection tank, it's important to make sure you have a place for the water to drain. These models work great in a basement or bathroom with a drain on the floor as they rely on gravity to move the water. Some models also include a built-in pump to help move water up and out a window or into a sink above the dehumidifier.

Humidistat

A humidistat measures the humidity in the air and adjusts the dehumidifier accordingly. This lets you dial in the precise humidity level you desire. Once that desired level is reached, the machine will shut itself down. When humidity begins to climb, the humidistat alerts the dehumidifier and puts it back to work. By running the dehumidifier only when necessary, the device will typically enjoy a longer lifespan.

Low-Temperature Setting

Allows dehumidifiers to operate down at temperatures down to 41° F.

Two Speed Fan

Models that offer multiple fan speeds are both quieter and more efficient.

Shop Dehumidifiers

In Summary

Moist air is a breeding ground for allergens, mold, and mildew. Dehumidifiers remove moisture from the air to keep you healthy and comfortable while protecting your home from destructive growths. If the air in your home feels muggy or if you notice condensation on the insides of your windows, you should be using a dehumidifier.

When shopping for a dehumidifier, go for the largest model you can afford. Depending on the size of the space, smaller models may be able to handle the job. However, larger models are faster, more efficient, and more reliable.

Figure out how you'll manage the water removed from the air. With a continuous or direct drain dehumidifier, you can attach a hose and let gravity pull the water toward a drain. Look for a model with a built-in pump if you plan on using a drain that sits above your dehumidifier. Or, stick to the manual method of emptying the collection tank when it fills.

If you still have any questions, please don't hesitate to reach out to us at 847-954-4100 or you can also check out our top picks for the Best Dehumidifiers in 2021. Either way, we want to make sure you find the perfect dehumidifier to fit your specific needs.