Best Crawl Space Dehumidifier [8 Reviewed]

This post was last updated on: December 1, 2024
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Calling them “crawl spaces” already makes them sound like something out of a horror movie. Adding humid air to the areas under your roof or floor can turn them into truly terrifying places. Mold, mildew, insects, and other pests can make their home in a damp area under your house.

However, it’s fairly easy to lessen that horror by taking the humidity out of the air, and the most efficient way to do that, as you may have guessed, is with a dehumidifier. These marvelous machines yank water vapor out of the air and turn it back into liquid that you can dump or drain.

If you type “best dehumidifier for crawl space” into Google, you’ll get plenty of results, and it can be hard to know where to begin. For crawl space and under house areas, specifically, you’ll probably want to get a unit that’s easy to install, adjust, and empty, since you probably don’t want to spend too much time down there.

Before you fall down the rabbit hole of crawl space dehumidifier reviews, take a look at this list of our eight favorite crawl space dehumidifiers, along with some general information about these appliances to help you make your selection.

Quick List: The Best Dehumidifiers for Crawl Spaces Compared

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1. AlorAir Basement/Crawl Space (90 PPD) – Best High End Crawl Space Dehumidifier
2. AlorAir Basement/Crawlspace (198PPD) – Best Crawl Space Dehumidifier with Pump
3. AlorAir LGR 85 Dehumidifier with Pump (85 PPD) – Most Portable
4. AlorAir (55 PPD) – Best Crawl Space Dehumidifier for Small Spaces
5. Aprilaire 1820 Crawl Space Pro (70 PPD) – Best Commercial Grade Crawl Space Dehumidifier
6. Dri-Eaz Revolution LGR (80 PPD) – Best Under House Dehumidifier
7. Dri-Eaz PHD 200 with Pump (75 PPD)
8. Thermastor Santa Fe Compact 2 (70 PPD) – Best Compact Crawl Space Dehumidifier

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Picks for the Best Crawl Space Dehumidifiers

1. Best High End Crawl Space Dehumidifier – AlorAir Basement/Crawl Space (90 PPD)

If you have a crawl space that’s worthy of a horror movie, then you might consider the AlorAir 198 PPD option. This dehumidifier is strong as a tank, and it comes with a five-year warranty, so you know AlorAir is serious about its quality.

It will handle up to 2,600 square feet, which makes it perfect for a large under house area or basement. With an efficient and quick process for defrosting, you won’t have to worry about protecting it in temperatures as low as 36°F.

With an epoxy coil coating, this AlorAir dehumidifier protects all its parts from corrosion – a common problem with appliances that collect moisture. The unit also comes with a built-in filter, which is easy to slide out and clean.

Product Details and Specifications

• Suitable for Spaces up to: 2,600 sq. ft.
• Water Removal: 90 PPD (AHAM*), 198 PPD (SATURATION)
• COP: 2.88 L/KWH
• Outlet Airflow (max.): 210 CFM, 350 CMH
• Built-in Pump: No
• Products Dimensions (L×W×H): 23.2″×15.2″×17.7″
• Warranty: Yes

*Note: AHAM stands for Association of Home Appliance Manufacturers. This number refers to the pints per day under average testing conditions of 60% humidity and 80°F. This is a realistic measure of how much water your dehumidifier will pull out of the air on a day-to-day basis.

Saturation refers to how well the dehumidifier works under extreme conditions of 90% humidity and 90°F. That number is the absolute maximum amount of water the dehumidifier will gather in a day.

COP is a measure of efficiency. The higher a dehumidifier’s COP rating, the more energy-efficient it is. CFM stands for cubic feet per minute, and CMH stands for cubic meters per hour. Both refer to how much air a dehumidifier can process in a certain amount of time.

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2. Best Crawl Space Dehumidifier with Pump – AlorAir Basement/Crawlspace (198PPD)

Dehumidifiers without pumps require gravity to work, which means you’re somewhat limited in where you can place them. They need to be elevated. With the addition of a pump, however, this AlorAir model can be placed anywhere, and is thus more easily installed.

Plus, all cables on this dehumidifier with a pump feature quick connect-plugs. As a result, installation and maintenance are easy. Like other AlorAir offerings, this dehumidifier has epoxy powder coating on its coils to prevent corrosion.

Included with this dehumidifier are a remote control system, automatic humidistat controls, low-temperature operation, and a hot gas valve defrosting system.

Product Details and Specifications

• Suitable for Spaces up to: 2,600 sq. ft.
• Water Removal: 90 PPD (AHAM), 198 PPD (SATURATION)
• COP: 2.88 L/KWH
• Outlet Airflow (max.): 210 CFM, 350 CMH
• Built-in Pump: Yes
• Products Dimensions (L×W×H): 23.2″×15.2″×17.7″
• Warranty: Yes

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3. Most Portable – AlorAir LGR 85 Dehumidifier with Pump (85 PPD)

The AlorAIr LGR 85 dehumidifier is specifically designed for use in water- and flood-damaged areas. This compact unit is easy to transport. With a stackable design, it conserves floor area during flood restoration, which means more units will fit into a smaller area.

Additionally, the LGR 85 is waterproof, which means if it has to sit in a few inches of water, you don’t have to worry about the circuit board being compromised. It comes with a digital humidistat control with LCD, a condensate pump, and a hot gas defrosting system.

This unit is great for warehouses, storage areas, crawl spaces, and basements. Plus, it is easy to operate and maintain. Lastly, for those of you who can’t stand appliances that clash with your décor, the LGR 85 comes in different colors. You can choose between red, green, blue, and yellow.

Product Details and Specifications

• Suitable for Spaces up to: 2,300 sq. ft.
• Water Removal: 85 PPD (AHAM), 190 PPD (SATURATION)
• COP: 2.88 L/KWH
• Outlet Airflow (max.): 210 CFM, 350 CMH
• Built-in Pump: Yes
• Products Dimensions (L×W×H): 22.8″×13.7″×17.3″
• Warranty: Yes

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4. Best Crawl Space Dehumidifier for Small Spaces – AlorAir (55 PPD)

The AlorAir dehumidifier is perfect if you have a relatively compact crawl space. Simply put, it’s the best dehumidifier for its size. This dehumidifier will remove 55 pints of water per day without driving up your energy costs.

Since there’s no tank in the unit, you don’t have to worry about constantly draining water. However, as with most crawl space dehumidifiers, you do need to set the hose up so that the water can flow directly into a drain.

You’re also getting a dehumidifier that comes with internal corrosion protection, which is intended to protect from Freon leakage. This is a common problem with dehumidifiers, and AlorAir uses this technology to mitigate it.

Plus, this dehumidifier comes with a remote control. If you need to make a change to the settings, you don’t actually have to get down into the crawl space with the unit. Just use your remote and make those adjustments from the comfort of your recliner.

Product Details and Specifications

• Suitable for Spaces up to: 1,300 sq. ft.
• Water Removal: 55 PPD (AHAM)*, 120 PPD (SATURATION)
• COP: 2.47 L/KWH
• Outlet Airflow (max.): 130 CFM, 230 CMH
• Built-in Pump: No
• Products Dimensions (L×W×H): 19.2″×12.2″×13.3″
• Warranty: Yes

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5. Best Commercial Grade Crawl Space Dehumidifier – Aprilaire 1820 Crawl Space Pro (70 PPD)

Aprilaire’s 1820 dehumidifier is perfect for your sealed basement or crawl space area. It will remove up to 70 pints of water from the air each day. Plus, it has a movable control panel that you can place on the side or top of the unit so you can easily access it whenever you need to.

A simple, intuitive display makes setting up the Aprilaire 1820 quick and easy. It doesn’t have a bucket or tray that requires emptying, and it comes with a built-in filter that only requires changing once a year. Plus, this high-quality dehumidifier is designed to last for the long haul.

The Aprilaire 1820 comes with aluminum coils that are corrosion-resistant, which helps to prevent leaks. Additionally, it has a five-year warranty, so you know Aprilaire is serious about its product.

Product Details and Specifications

• Suitable for Spaces up to: 2,200 sq. ft.
• Water Removal: 70 PPD (AHAM)
• COP: 2.1 L/KWH
• Outlet Airflow (max.): 140 CFM, 200 CMH
• Built-in Pump: No
• Products Dimensions (L×W×H): 25″×12.5″×12.5″
• Warranty: Yes

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6. Best Under House Dehumidifier – Dri-Eaz Revolution LGR (80 PPD)

The Dri-Eaz Revolution LGR is a compact, commercial-quality dehumidifier. If you have a large project, this is the perfect unit. Despite its modest size, it will dry nearly as much as some of the big boys, taking up to 17 gallons of moisture out of the air every day.

If you need to dry out heavily saturated areas, use the Dri-Eaz Revolution LGR. It will continue dehumidifying until your floors, walls, and carpet are all completely dry. It’s compact, so you know it will fit wherever you need to use it.

Dri-Eaz also throws in a limited lifetime warranty on this unit, covering six years on compressors and coils, and one year on parts and labor. You’ll also notice a humidistat that displays the current humidity conditions and temperature.

This high-quality dehumidifier will handle up to 7,000 square feet, so if you have a large area that needs drying, this is the unit for you.

Product Details and Specifications

• Suitable for Spaces up to: 7,000 sq. ft.
• Water Removal: 80 PPD (AHAM)
• COP: 2.21 L/KWH
• Outlet Airflow (max.): 180 CFM
• Built-in Pump: No
• Products Dimensions (L×W×H): 21.5″×12.5″×17.6″
• Warranty: Yes

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7. Dri-Eaz PHD 200 with Pump (75 PPD)

The Dri-Eaz PHD 200 dehumidifier is a great unit if your project needs commercial-grade power. Designed to work in areas up to 15,000 square feet, this powerful appliance is built for warehouses, but will work just as well in a very large basement or crawl space.

Considering this dehumidifier’s power, it’s priced quite reasonably. The digital controls are easy to read, even in the dim light of a crawl space. It can be placed on the floor, or you can purchase the optional kit to hang it from the ceiling.

Included with this offering from Dri-Eaz are a 20-foot drainage hose, a detachable power cord, and a disposable air filter. With all of these features, the PHD 200 is great at controlling the humidity where you may experience rot, mildew, corrosion, or even mold.

Product Details and Specifications

• Suitable for Spaces up to: 15,000 sq. ft.
• Water Removal: 75 PPD (AHAM), 120 PPD (SATURATION)
• COP: 2.88 L/KWH
• Outlet Airflow (max.): 180 CFM
• Built-in Pump: Yes
• Products Dimensions (L×W×H): 22″×12.5″×17.6″
• Warranty: Yes

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8. Best Compact Crawl Space Dehumidifier – Thermastor Santa Fe Compact 2 (70 PPD)

One of the best units on the market for a medium-sized crawl space is the Santa Fe Compact 2. At 12 inches tall and 12 inches wide, it can fit into tight areas where bulkier dehumidifiers simply can’t. With this unit, you’ll get high-quality and innovative features.

For example, the Santa Fe Compact 2 comes with horizontal and vertical exhaust outlets, plus optional hang kits and condensate pumps. Other conventional units don’t perform as effectively or efficiently as the Santa Fe Compact 2. Plus, it’s high-efficiency, exceeding all Energy Star regulations.

Since this unit is designed with crawl spaces in mind, it works well even when the temperature begins to drop. You’ll get superior air filtration with high-quality filters built-in. Plus, the Santa Fe Compact 2 offers auto-restart in the event you lose power.

This extremely powerful and compact dehumidifier is great for crawl spaces and basements up to 1,800 square feet. It’s simple to install and easy to maintain, which means it could be the ideal unit for your home.

Product Details and Specifications

• Suitable for Spaces up to: 1,800 sq. ft.
• Water Removal: 70 PPD (AHAM), 120 PPD (SATURATION)
• COP: 2.4 L/KWH
• Outlet Airflow (max.): 150 CFM
• Built-in Pump: Optional
• Products Dimensions (L×W×H): 12″×12″×21″
• Warranty: Yes

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Picking a Dehumidifier for the Crawl Space under Your House

If you’re not familiar with dehumidifiers and how they work, then you may have questions swirling around inside your head. Fortunately for you, we’re here to answer them.

Why Do You Need a Dehumidifier under the House?

There are many areas throughout the US where it’s not uncommon to find houses with crawl spaces – empty areas under the roof or floor that allow wiring and plumbing to pass through. You want to be sure you dehumidify your crawl space so your home and foundation are protected against rot and mold.

Typically, a crawl space will only offer about three feet of vertical height and be enclosed on all four sides. Since it’s usually pretty tough for a full-grown adult to get into these areas, it’s difficult to know just how things look under your floor.

If you don’t dehumidify your crawl space, you run the risk of the area getting very damp, which could result in mold, rot, and even structural problems. Eventually, these problems can wind up impacting the very foundation of your home.

When the outdoor humidity rises up over 70%, it’s safe to say that the air in your crawl space is even more humid, since it’s enclosed. This means that you wind up with condensation on the joists and beams beneath your house.

This is primarily due to the humid, warm air from the outside seeping its way into your house where the foundation is typically cooler. At that point, the air cools down, which in turn increases the humidity under your home.

That’s why it’s so important to make sure your crawl space is dehumidified. Installing a dehumidifier isn’t difficult; however, you will need some basic knowledge of the layout of your crawl space to get it done.

How Do You Dehumidify a Crawl Space?

First, find a dehumidifier that works best for your crawl space. We’d also recommend that you find one that is energy efficient. Once you have it where you want it and set up the hose to drain the collected water, turn the dehumidifier on. Yes, it really is that simple!

Most dehumidifiers will shut off once they’ve dried the air. In the future, when the humidity gets too high, the humidistat will automatically kick on and work to drive the moisture level back to where you want it. Most dehumidifiers recommend a setting around 50%.

When you’re looking for a dehumidifier for your crawl space, be sure to look for one that doesn’t require a lot of maintenance. It can become frustrating to move in and out of your crawl space on a regular basis to perform routine maintenance on your dehumidifier.

If you’re like us and you don’t want to get off your rear at all, find a dehumidifier with a remote control. This way, you can easily monitor your dehumidifier inside your home without having to mess around with your crawl space.

Look for features like filters that don’t require much cleaning, tanks that are easy to empty, and dehumidifiers with attached drain hoses. You know your crawl space better than anyone, so determine what makes the most sense for you.

What is the Ideal Crawl Space Humidity Level?

If you want to prevent damaging the structural integrity of your home, you want to ensure that your crawl space doesn’t have a high humidity level.

Typically, to prevent mildew and molds from thriving, you need to keep the humidity below 70% at the very highest. This is the humidity at which these intruders begin to develop and grow. However, some molds will grow even at levels below that point, so 70% is not the ideal target.

Your best bet at keeping molds, mildew, rot, and other detriments at bay beneath your home is to keep your humidity level at or around 50%.

Some Acceptable Crawl Space Humidity Levels

While you could reduce the humidity in your crawl space to as low as 30%, you may not want to make it too dry. Allowing the beams and flooring in your home to get too dry can lead to splitting, cracking, and brittleness in the wood.

Keep the humidity in your crawl space between 40-50%, and you shouldn’t experience any problems. Stabilize the humidity in your crawl space to a point where mold and mildew won’t grow, but your wood still has the moisture it needs to prevent overdrying.

How Much Does a Crawl Space Dehumidifier Cost?

Dehumidifiers can range greatly in price, and the price you pay depends on the features you want or need. One metric to keep in mind, for example, is the size of your home. If you have a large home, you’ll need a dehumidifier than can handle more square footage.

Those that don’t have a large home can probably expect to pay between $200 and $400 for a properly-sized unit. These are great for crawl spaces and basements that don’t need a lot of dehumidifying.

If you want additional features like drainage hoses, extra-large tanks, or low-temperature operation, then you should expect to pay on the high end of that range. Usually, these dehumidifiers can handle 25 to 70 pints of moisture per day.

Low-maintenance and larger capacity dehumidifiers are going to run you a bit more. These are specifically designed for a larger crawl space or basement, so you’ll be looking at the $800 to $1,200 range. Of course, the price will depend on features like capacity, efficiency, and drainage.

As with most appliances in your home, there are also additional costs associated with owning a dehumidifier. For example, you might want to purchase a hygrometer, which is a tool that measures the ambient humidity level.

These usually cost between $15 and $80. If you want an electronic one, you’ll pay a little more. However, this will allow you to take measurements from your crawl space without being forced to actually go down there.

Lastly, don’t forget about the cost to operate your dehumidifier. Even the most energy-efficient models will bump your energy bill up a bit. You can probably expect to see an increase ranging from $35 to $420 per year. Find an Energy Star dehumidifier to help keep that number to a minimum.

Where Should a Crawl Space Dehumidifier be Placed?

Something that is critical for dehumidifier operation but few people consider is where to install the unit. You want to be sure your dehumidifier is in an area where the discharge airflow isn’t restricted.

If possible, try to find a few concrete blocks on which to place your dehumidifier. A lot of units offer additional hang kits; however, more often than not this winds up transferring the noise to the room right above it.

Be sure to place your dehumidifier in a spot where it can easily drain. If you need to, purchase an additional condensate pump if you don’t already have one. Keep the unit as level as possible so you don’t wind up with standing water in your crawl space.

Some dehumidifiers for crawl spaces come with drainage buckets, but your best bet is probably to get one that offers a drain hose. Put the unit in a convenient place where you can easily make adjustments based on the time of year, clean it, or change the filter.

Once you have everything all set, you shouldn’t need to adjust it much. However, not all crawl spaces are created equal. The location of your dehumidifier will greatly depend on the design and layout of your crawl space.

With a U-shaped crawl space, for example, you’ll want to install your unit right in the middle of the U. Separate the intake and the exhaust by using flexible ducting. On the other hand, if you have a rectangular crawl space, keep your unit at one end.

If you have a divided crawl space, you might have to extend the exhaust from one area to the other. Make sure a path for return air is available so it circulates between the sections.

Where you place your dehumidifier in your crawl space can make a significant difference in how well your unit performs. Take a moment to determine exactly where it will run most efficiently before just throwing it in the space and plugging it in.

Can You Use an HVAC System to Dehumidify a Crawl Space?

If you already have a duct system in your crawl space, you may be considering simply using your HVAC system to dehumidify the area. You might think the air from the system will aid in keeping the air in the crawl space dry.

While this sounds great in theory, you may run into problems during the swing seasons like spring and fall. If you have an oversized air conditioner in your home, you may run into more problems than you’re actually solving, overtaxing the unit’s ability to handle moisture.

It will come as no surprise that we would recommend using a dehumidifier in your crawl space. The HVAC system in your home is designed for the conditions within your home, not for the crawl space beneath it. A good dehumidifier can even help your AC run more efficiently.

Will a Regular Dehumidifier Work in a Crawl Space?

The short answer is yes, but it isn’t recommended. Regular dehumidifiers often require frequent emptying of their moisture capture containers, so accessibility will most likely be an issue.

Furthermore, their size may not allow for installation in your crawl space. In addition, the moisture removal capacity of a regular dehumidifier may not be up to par with what your crawl space needs.

Crawl Space Fan vs. Dehumidifier

The primary difference between a fan and a dehumidifier is how each one works. The former moves air through your crawl space, while the latter draws air through the unit and actually removes the water vapor.

Fans are an inexpensive way to keep the air your crawl space well-circulated and fresh. They are easy to install, usually fitting into vents or windows to pull in air from outside the home. While a dehumidifier requires drainage or emptying, a fan doesn’t require this type of upkeep.

However, unless you live in a very dry climate, a fan is only going to go so far. If the air it pulls in from outside is already humid, it won’t evaporate much moisture from indoors. You’re better off using a dehumidifier if you have a problem with dampness.

Dehumidifiers are also beneficial in that they allow you to know exactly how much water vapor is being removed. You can control the humidity level in the space and make adjustments as necessary.

Even though they aren’t as easy to use, today’s dehumidifiers are not as complex as some people think. They do require regular upkeep, but usually, this only requires visiting your crawl space a few times a year.

Overall, choosing between a fan and a dehumidifier depends largely on what you want. You’ll have more control with a dehumidifier for your crawl space. You’ll wind up spending more, but you’ll have the peace of mind of knowing the humidity in your crawl space is exactly where it should be.

The Last Word in Under House Dehumidification

When it comes to the crawl space under your house, it’s almost always best to err on the side of caution. Mold, mildew, and rot are large problems to solve, so it’s best to prevent them from ever getting a foothold in your home in the first place.

Just keep your crawl space dehumidifier running and it’ll take care of everything for you. Sure, you might have to get dirty a few times a year to maintain it, but it’s worth it to know everything is as it should be beneath your home.

The upfront cost can be a tough pill to swallow, especially if you have a larger home and need a unit that can handle a lot of square footage. However, it’s much cheaper than treating for mold later or discovering wood rot in the joists of your home.

As you can see, there are plenty of excellent choices when it comes to crawl space dehumidifiers. So get off your butt, get under your house, and determine exactly what you need. You should have no trouble finding the right one.