By Tom Scalisi | Updated Dec 29, 2021 8:24 PM

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Crawl spaces are dark and dusty, and air quality isn’t always at its finest. If the humidity level climbs (which it often does) in a sealed crawl space , the excess moisture can cause mold, mildew, rot, and other issues.

Instead of letting this space grow mold and bacteria, the best crawl space dehumidifier is your solution . The machine hangs from the floor joists in a crawl space, pulling the humid air, removing the moisture, and sending the fresh, dry air back out. If your crawl space is humid, keep reading to learn more.

No one wants mold or mildew growing under their feet, and the best crawl space dehumidifier will help ensure it doesn’t. While these dehumidifiers work very similarly to indoor and basement units, there are some differences and points to keep in mind when shopping for one. The following sections will delve into the top considerations to think about.

Choosing the proper size dehumidifier is critical to ensure it’s able to handle the task at hand. If it’s too small, it won’t be able to remove humidity from an entire crawl space. If it’s too large, it’ll use more electricity than necessary and cost too much upfront. Here are some points to consider.

Humidistats are an important feature to look for in the best crawl space dehumidifier. They allow the user to set the level of humidity for the dehumidifier to maintain. The unit will run when the humidity levels climb above the setting and shut off when they drop below it. Why are they important? Consider these points:

Crawl spaces are popular in many areas across the country, and many of those areas get very cold in the winter. Leaving a crawl space dehumidifier exposed to the elements can freeze the condensation coils and destroy the machine. For this reason, a defrosting system is essential.

The defrosting system maintains a warmer temperature within the dehumidifier. This prevents cold air from freezing the condensed water or coils, allowing the unit to run much longer. Even in areas where temperatures aren’t likely to freeze, it can be an important feature. In fact, it only takes one time for a freeze to break a coil.

Like household dehumidifiers, crawl space dehumidifiers collect the water they remove from the air. Unlike the household models, heading to the crawl space twice a day to remove a tank isn’t possible or practical. Instead, these models drain, but some models or scenarios require condensate pumps to work effectively.

Units equipped with condensate pumps push the water wherever it needs to go. Whether through a long run of hose or a drain that’s only accessible above the unit, a condensate pump will push the collected water out of the crawl space so you don’t have to crawl under and empty the tank.

The average home dehumidifier generates a noise similar to the hum of a window air conditioner, and the larger the capacity, the louder the device will be. Most small dehumidifiers produce between 30 decibels (comparable to a normal conversation) and 45 decibels (comparable to the hum of a refrigerator), but manufacturers aren’t required to list the noise levels on their units.

Reading customer reviews is the best way to determine how noisy a specific dehumidifier will be. But, be advised that placing the unit on a level and padded surface can also help reduce noise.

Dehumidifiers can provide a continuous flow of fresh, dry air in your crawl space, resulting in an energy-efficient solution that improves the air quality and keeps mold growth at bay all season long. Small dehumidifiers that are suitable in crawl spaces will likely run on 280 to 300 watts of power, meaning that they will consume 4 to 5 cents of power per hour. Per year, if your dehumidifier is on for 9-10 hours per day, this equates to roughly $150.

However, 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 ample greenhouse gas emissions.

There are a few other features that might make a particular model the best crawl space dehumidifier for your needs.

Before selecting a dehumidifier, it is important to measure your space to know which model will be most effective. It should also be placed where the air flow is not blocked and where the noise level can be heard the least. As some dehumidifiers also require draining, so your model should be placed where it can be accessed as easily as possible.

While some models can be installed without professional help, some models that require connection to an HVAC system may require a contractor to install. If you do decide to install it yourself, you may require a drill or screwdriver, a hammer and nails, metal straps and PVC pipes, and/or rubber tubing depending on the model you choose.

Between choosing the right size, deciding whether a pump is necessary, and picking convenience options like remote controls and filters, there are a lot of decisions. The following list aims to streamline the shopping process a bit, as it’s a collection of some of the best crawl space dehumidifiers on the market.

AlorAir’s Commercial Dehumidifier is worth checking out for anyone hunting for a medium-capacity unit to fix their crawl space moisture issues. This model features a 113 PPD capacity in saturation conditions and 53 PPD AHAM conditions, making it suitable for spaces up to 1,300 square feet (which includes most residential crawl spaces). It comes with a filter to prolong the life of the unit, which is easy to access from the side of the machine.

Besides its capacity, this gravity-draining unit has plenty of desirable features. Among those features are an automatic defrost setting to protect the coils from freezing and memory restart, allowing this unit to pick up where it left off after a power outage. This model from AlorAir is also compatible with a remote control for easy settings and readings, though it is a separate purchase.

Those with smaller basements could find this compact 22 pint GE humidifier the ideal solution, yet despite the low cost it has all the features you would find on the best basement dehumidifiers.

The top-mounted LCD screen provides control over the on/off timer, and humidity level. Once the latter is set, the Smart Dry function means the dehumidifier can be left to run automatically. The three-speed fan boosts air flow when necessary. Dust is removed by a washable filter. There is auto restart should power be interrupted, and auto defrost.

Buckets generally have an overflow shutoff, but the front-mounted bucket on the GE humidifier also provides a useful audible alarm. It holds 8.5 pints.

Large spaces with serious excess moisture issues might require a bit more power, and a heavy-duty upgrade unit like AlorAir’s Basement/Crawlspace Dehumidifier might be the way to go. This model features a 198 PPD rating in saturated conditions, giving it enough power to cover spaces up to 2,600 square feet.

This model from AlorAir isn’t just capable of handling larger spaces, it also has convenience features like automatic defrost and compatibility with a remote control (though it’s a separate purchase). If the power goes out, the automatic restart will kick on and begin dehumidifying without user input.

This unit comes with a condensate pump already installed, allowing users to remove water with ease, pumping the water away instead of relying solely on gravity. This makes for more versatility during crawl space dehumidifier installation.

The hOmeLabs Energy Star Dehumidifier, the largest crawl spaces can stay dry and comfortable. The hOmeLabs dehumidifier comes with a removable 1.6-gallon collection tank and 50 PPD, but it operates best when connected to a drain hose (not included) for hands-free emptying.

Designed to remove humidity from areas of up to 4,500 square feet, the hOmeLabs dehumidifier is powerful enough to tackle the toughest humidity problems. It is also simple to operate, and users can select from a timed mode or select continuous mode with the digital control panel, which means the unit will run for 24 hours until it’s shut off or until the tank fills.

If the power goes out, this unit will automatically turn back on and resume the last setting mode. The removable and reusable filter can also be rinsed and re-inserted.

For smaller crawl spaces, large units are a waste of money and energy consumption. In those smaller areas, a unit like this one from AlorAir is worth checking out. This model features the capacity to remove up to 55 PPD AHAM from crawl spaces and other areas up to 1,300 square feet, with a maximum PPD in saturation of 120. This smaller dehumidifier is also Energy Star certified, making running it more affordable.

This model has plenty of automatic features adding to its appeal. It has an automatic defrost mode to keep the coils from freezing during colder weather, as well as a removable filter to keep those coils clean.

The AlorAir features a gravity drain as well as compatibility with a remote control for maximum convenience (though it is a separate purchase). Also, should the power go out, this unit will remember its settings and continue to dehumidify when the power comes back.

When it comes to portable crawl space dehumidifiers, this GE model is a high-performance device that can remove 50 PPD from a 1,500 square feet area, and provides accurate control over humidity. It can run non-stop if required, and a three-speed fan increases air flow to clear damp areas more quickly.

There is an audible alarm when the bucket is full, and an alert when the air filter needs to be rinsed. It also has automatic restart in the event of power loss, and auto defrost. At 15 pints, bucket capacity is better than many.

Constant draining is an option, and this is where GE’s main benefit lies: Where many dehumidifiers rely on gravity for this, the GE model can pump the water up to 16 feet from the unit to a convenient sink or other outlet. The hose is also included.

A standard dehumidifier will improve the air quality of your space by limiting musty odors, mold, and mildew. When you add an air purifier to the mix, then you’re also directly reducing dust mites, pollen, pet dander, and other allergens at the same time. With this hybrid model from Tenergy, you’ll get double the comfort from one unit.

The dehumidifier feature can remove 750 milliliters of moisture per day in environments with an 80 percent humidity level at 86 degrees Fahrenheit. When the 33-ounce/1-liter water tank reaches full capacity, an automatic shutoff will prevent overflow. Using a true HEPA filtration system, this small dehumidifier can also remove up to 99.97 percent of microparticles and allergens from the environment at the same time.

It may cost more than a standard small dehumidifier, but having the benefits of an air purifier in the same unit can save both space and money in the long run. This small dehumidifier is ideal for spaces up to 200 square feet, and it runs at a quiet 35 to 42 decibels.

Choosing a dehumidifier is difficult if you do not know what you need for your space. One of the best dehumidifier units for crawl spaces is the ALORAIR dehumidifier, capable of handling areas up to 1,300 square feet with a powerful 120 CFM rating. This unit also includes a built-in filter and a useful automatic defrost feature.

Alternatively, if you need a unit with a smaller price tag, the GE 22 pt. dehumidifier is a great option for spaces up to 500 square feet. Highlights of this unit include a three-speed fan, tank-full alert system, and an LCD display.

Using a dehumidifier in your crawl space ensures that mold, mildew, and moisture are removed, stored items within are safe, and the humidity level in your home is regulated. Our curated list represents some of the best dehumidifier brands and key factors including coverage area, air flow, pint capacity, and special features.

The top picks are made for a variety of crawl spaces of 200 to 6,500 square feet and come with powerful 22 to 200 CFM ratings. Many units come with high pint capacities of up to 198 PPD, so you don’t have to worry about emptying the unit frequently. Some also have self-emptying tanks to limit dehumidifier maintenance. As for special features, several dehumidifiers we selected come with automatic shutoff and defrosting, as well as removable and reusable filters.

Even with that extensive background on choosing the best dehumidifier for crawl space areas, there might be some additional questions popping up. This section aims to provide answers, as a collection of some of the most frequently asked questions about crawl space dehumidifiers.

Technically, you could, but they aren’t built for the rigors of crawl space life. Regular dehumidifiers’ coils aren’t durable, they rarely feature defrost functions, and most have tanks that require emptying. Also, crawl space dust is sure to limit an indoor unit’s lifespan.

As crawl spaces are likely to be very damp, a dehumidifier with a 50 pint tank or more is recommended to allow for ample drying.

You shouldn’t set a crawl space dehumidifier to a temperature, but rather a moisture level. As a general rule, you want to keep that space under 55 percent humidity, so setting the unit to 50 percent should do the trick.

You’ll want to set up the dehumidifier in an area where it can draw in moist air and push out dry air without obstruction. It’s best to set it up in the center of the crawl space.

The average dehumidifier will reduce the humidity in a crawl space in 8 to 10 hours depending upon the size of the space and the current moisture levels.

Cleaning a dehumidifier should be relatively straightforward, most parts just needing to be wiped down with a damp cloth. It’s possible the reservoir may have a build up of limescale, which can usually be removed with white vinegar or lemon juice. An air filter usually needs a quick rinse once a month. To ensure the longevity of your machine it is vital you follow manufacturer’s instructions.

Dehumidifiers don’t require much maintenance other than cleaning or changing the filter every 6 to 12 months. If maintained properly, you can expect your dehumidifier to last around 5 years.

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