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Excess humidity can invite mold and mildew into any part of your home, but a crawl space dehumidifier can help get ahead of the problem. The area under your home can act as a breeding ground for problems that migrate to every part of the house. Crawl space humidity fluctuates, with one Oak Ridge National Laboratory (ORNL) crawl space study finding relative humidity levels swing from under 30 percent to over 80 percent within a single month. Crawl space dehumidifiers employ specific features to address moisture in low-lying and out-of-the-way areas. We’ve chosen the AprilAire E070 Pro as our best overall crawl space dehumidifier for its mix of features and robust performance. However, we also have some suggestions for a variety of living spaces and budgets.
How we selected the best crawl space dehumidifiers
I have been helping Popular Science educate people on the importance of managing moisture in the home. I have outlined the differences between humidifiers and dehumidifiers while reviewing and recommending everything from small dehumidifiers to powerful dehumidifiers for basements. My investigations have looked into how these machines work, their essential stats, an overview of common customer complaints about them, and additional features that solve those complaints.
Now, I’m turning to the near-subterranean area of the crawl space. This space changes the game for dehumidifiers. You don’t want to have to venture into your crawl space every day to empty a tank and, being farther from your living quarters, things like sound level volume matter considerably less. At the same time, dank crawl space air requires more power from a dehumidifier if you want maximum efficacy. We have based our choices on some tips from expert builder Matt Risinger and his experiences with crawl spaces.
The best crawl space dehumidifiers: Reviews & Recommendations
The best crawl space dehumidifiers are really meant to be set and forgotten, at least for the day-to-day. They’re boxy, not beautiful, and tackle the unique challenges of the area below your home. So, while they may look utilitarian in nature, that’s exactly what you want for a device like this.
Best overall: AprilAire E070 Pro
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Why it made the cut: This reliable dehumidifier is perfect for the typical home crawl space.
Specs
- Coverage: 2,200 square feet
- Max capacity: 70 PPD
- Included drainage: Gravity
- Size: 12.5 x 25 x 12.5 inches
- Weight: 56 pounds
Pros
- Perfect coverage for most crawl spaces
- Made with corrosion-resistant aluminum coils
- Comes with great gear
- Easy installation and controls
Cons
For most crawl spaces, the AprilAire E070 Pro will give you the best experience, from its compact size that can fit through small entryways and in more cramped areas to its 2,200 square feet coverage area that can accommodate most crawl spaces. It’s also made with aluminum coils, which are shown to resist corrosion so long as they aren’t submerged in water. And if that’s not enough to suggest a good amount of longevity, the 5-year warranty should.
The front of the machine has a small digital display to help you get your settings right in quick order. To save on energy, it will automatically shut off when not needed, and to save itself, it has overheating protection and an automatic defrost function. This machine can largely function in a hands-off manner.
The E070 Pro also comes with plenty of gear to get you started, including a drain fitting and 10 feet of drain tubing. It also uses a washable MERV 8 filter to cleanse the pollen, dust mites, and mold spores from your air. While it’s technically nicer to have a built-in condensate pump, this gravity solution can drain to other systems you already have in place or a separately purchased pump if you need it.
Best-rated: Moiswell 145 Pints
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Why it made the cut: People love this powerful dehumidifier for its convenience and affordability.
Specs
- Coverage: 6,000 square feet
- Max capacity: 145 PPD
- Included drainage: Gravity and pump
- Size: 13.4 x 14.6 x 22.1 inches
- Weight: 62 pounds
Pros
- High ability-to-cost ratio
- Simple interface
- Convenient form factor
- 5-year customer support and Energy Star certified
Cons
The Moiswell 145 Pints is one of the most affordable mid-to-large crawl space dehumidifiers, and customers love it. While that could possibly be due to the price, it might also be for its relatively high power, simple touchscreen interface, or built-in pump to make getting water out of your crawl space easy. It could even be for its smaller than typical size, ideal for smaller spaces. Depending on your needs and budget, there are many reasons to like this dehumidifier.
So, what’s the worry then? Moiswell is pretty new. Their parent company, Inofia, appears to have been registered in 2021, and their site’s first blog entry is dated 2023. Compared to older, more established brands on this list (AprilAire made their first humidifier in 1954 and, additionally, have made many of the best whole-house humidifiers), that’s not a lot of time. And that’s especially true since you’ll want your dehumidifier for many, many years. However, we’re seeing happy customers at this time and are hopeful for the future. Plus, things like an Energy Star certification and a 5-year customer support guarantee show the start of a great brand.
Best splurge: AprilAire E080 Pro
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Why it made the cut: Though similar to the ever-popular E070 Pro, this one packs a considerably harder punch.
Specs
- Coverage: 4,400 square feet
- Max capacity: 80 PPD
- Included drainage: Gravity
- Size: 15 x 26 x 34 inches
- Weight: 88 pounds
Pros
- Excellent for larger crawl spaces
- Premium abilities
- Rated Energy Star most efficient
- Not considerably more expensive than the E070 Pro
Cons
In many ways, you can look at this dehumidifier as a slight upgrade to AprilAire’s E070 Pro model, our overall best pick. Like the former model, it is also made with corrosion-resistant aluminum coils and has a washable MERV 8 filter, but it does not have a built-in pump. You’re getting the same reliable humidity pull in a very similar form factor.
But there are some differences. For one, you’re getting an extra 10 pints maximum humidity pull per day. Secondly, its coverage range is much higher at 4,400 square feet, meaning it can handle crawl spaces that are quite large all on its own. While commanding a notable premium, at less than $200 more than the E070 Pro, the E080 Pro is perfect for a larger area and is a best value compared to buying two units suitable for mid-sized coverage.
Best design: Alorair Sentinel HDi90 with Condensate Pump
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Why it made the cut: This is a powerfully rated dehumidifier with a lot of convenience features.
Specs
- Coverage: 2,600 square feet
- Max capacity: 198 PPD
- Included drainage: Gravity and pump
- Size: 23.5 x 15.2 x 17.7 inches
- Weight: 70.5 pounds
Pros
- Pulls 90 PPD at typical conditions
- Energy Star certified
- Rare earth alloy tube evaporation
Cons
One issue with the naming conventions and stat reporting for dehumidifiers is that the pints per day (PPD) that they pull is typically measured under ideal conditions. Ideal for the dehumidifier, that is. So, when we say that a dehumidifier is 90 PPD, that means it gets 90 pints of water out of the air at rather hot temperatures and high relative humidity. This dehumidifier, for example, is measured by the manufacturer to get 198 pints in these saturated conditions. But what about normal conditions that you experience?
That’s where AHAM conditions come in. AHAM, or the Association of Home Appliance Manufacturers, has more reasonable conditions for a humidifier to work: 80 degrees Fahrenheit and 60 percent relative humidity. In other words, as temperature and humidity drop, the effectiveness of this dehumidifier doesn’t.
But this isn’t the only way that the Alorair will make your life more convenient. It uses MERV 1 filters for higher quality air output, rare earth alloys in its coils for a longer lifespan, a condensate pump, auto defrost and auto restart, and an easy-to-use control panel for targeted humidity settings. Unfortunately, its ability to have a thermostat-like remote control panel is gated behind an optional extra payment. While this is not the most expensive item on the list, the Alorair Sentinel HDi90 does have premium pricing, so we would have liked to have seen more come with it.
Best budget: Alorair 70 Pint Dehumidifier
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Why it made the cut: This dehumidifier provides great value and excellent affordability for smaller crawl spaces.
Specs
- Coverage: 1,000 square feet
- Max capacity: 70 PPD
- Included drainage: Gravity and pump
- Size: 15.4 x 11.2 x 11.4 inches
- Weight: 40 pounds
Pros
- Great cost-to-capacity ratio
- cETL listed and Energy Star certified
- Includes automatic defrost
- Lightweight for its class
Cons
- Best for small crawl spaces only
If you want one of the cheapest units and have a small sized crawl space, the Alorair 70 Pint Dehumidifier is for you. The budget factor, in this case, comes from the fact that it is rated for smaller crawl spaces of about 1,000 square feet. And, while it has a maximum capacity of 70 pints per day, it isn’t necessarily going to pull that unless your crawl space runs super hot (90 degrees) and has very high humidity. Instead, this dehumidifier is about keeping a slight problem at bay for the long haul.
More reasons to like this dehumidifier are its cETL safety listing, 19.6 feet of vertical water pumping, and MERV 1 filtration to remove about 95% of pollutants from the air it intakes. It runs pretty quiet at around 50 dB or less, meaning you should not hear it from within your home as you go about your day. So, for an easy and affordable time in your small-sized crawl space, give this unit a try.
Things to consider before buying crawl space dehumidifiers
What does it take to get a good crawl space dehumidifier, and what do all those stats, such as PPD and capacity, mean? We take a look and demystify the key parts of getting a crawl space dehumidifier installed in your home.
Your crawl space
Your crawl space is a bit gross and humid. Therefore, you buy and properly install a crawl space dehumidifier. Now, everything is fixed, right?
If your crawl space is open to the air, more humidity will probably still come in. Crawl space encapsulation—a more complex than it sounds process of more or less blocking off open air to your crawl space—will help. But, as experts will remind you, you’ll almost certainly still need a dehumidifier after encapsulation. In fact, with certain building codes, it could be required.
This is all to say, be aware of your crawl space’s makeup and construction. You’ll likely benefit from putting a hygrometer in your crawl space and checking it over the course of the next month or two after any changes, as well as during high humidity and high precipitation times in your region. You may also find talking to a local contractor experienced with crawl spaces in your region illuminating. They’ll not only know seasonal needs but may also have experience with other crawl spaces built and designed by the people who worked on yours.
Coverage and capacity
Opening doors and windows throughout your house aren’t only a great way to keep cool with minimal AC; it also helps circulate air through your house. Your crawl space is considerably less likely to get the same level of circulation, and they can only pull water out of air that gets in them. As a result, crawl space dehumidifiers will typically have large and powerful fans that increase air circulation, which makes their coverage higher.
We’ve found that typical crawl spaces are between 1,500 and 2,000 square feet, so many of the products on the list have a coverage area within or just above that range, but some are above it.
The next issue is a crawl space dehumidifier’s capacity, or ability to pull out water. The more, the better. This factor is measured in pints per day, or PPD for short. However, it should be noted that a dehumidifier’s ability to work differs depending on the temperature and relative humidity (RH) of the space. Typically, when manufacturers are reporting the PPD of a dehumidifier it is in an idealized condition with high humidity and temperatures. A 90 degree basement with 90% RH is going to have more humidity sucked out of it in a day than an art museum’s low humidity air, for example. Don’t automatically assume a high PPD dehumidifier is stronger or better for you, though it could be.
Drainage
When we talk about typical humidifiers, you’ll typically have one or two drainage options available. One is a manual dump tank, which fills up slowly, and the other involves a hose that you can feed into a sink or other drain.
With a crawl space dehumidifier, the first option is pretty bad. You don’t want to have to go down there often. Since gravity affects your ability to drain out of a hose and your crawl space dehumidifier will already be quite low, it can be difficult to position things right to take advantage of gravity alone. That’s where pumps come in handy, which add extra force to counteract any problems that gravity (and being at a low point) may cause.
In the above dehumidifiers, we discuss “included drainage” which tells us what the kit contains. Note that if you see “Gravity” it does not mean that you cannot use a pump, just that you will need to get one separately. In some instances, you may be able to get a better deal or better overall quality by draining a gravity dehumidifier’s waste water into a condensate pump.
In short, make sure that your crawl space dehumidifier has clear and easy ways of draining itself and that they will work with what your crawl space and the land around it has to offer.
Expert insights
To make sure we were getting the underbelly of the home done right, we talked with expert Matt Risinger, who has an eye for crawl spaces. Matt Rising is a building science expert and lead of The Build Show. Here’s a glimpse at our conversation:
What are the biggest mistakes people make when it comes to managing humidity in their crawl space?
Crawl spaces should be treated like a short basement. The best way to make a healthy crawl space is to eliminate the ventilation and make it a short basement. [Note: This process is referred to professionally as “encapsulation.”] We want to prevent soil vapors, including Radon and moisture, from coming up, and eliminate entryways for air to treat it like a basement. And, then, eliminate humidity.
Have you ever seen someone just pop in a regular dehumidifier in their crawl space? How did that work out over the long run?
As long as the ventilation to the crawl space is blocked, it can work well. But you need to fight the humidity intake of the space or you’ll run into problems quickly. If the space isn’t encapsulated, no matter how powerful the dehumidifier is, it won’t win the battle against moisture.
For the average person, is a DIY installation advisable?
Totally.
In your work, you talk a lot about good vs. bad crawl spaces. Is a crawl space dehumidifier essential, in your opinion, to a good crawl space?
If you have everything else in place, in perfect order, the dehumidifier is less necessary. But most crawl spaces are imperfect, so the dehumidifier gives us that extra bit of forgiveness. Crawl space humidity causes bad things in the house, so this gives us some insurance.
When it’s done right, and when a crawl space is made into a short basement, it can be a really good feature. Don’t shy away from them because you’ve had a bad experience in the past—they help remodels and give you good access to wiring and more. Anything that’s been bad can be retrofitted to become a good crawl space.
FAQs
Typically, the best crawl space dehumidifiers are going to cost around $600 at the lowest and $1,200 at the highest. People needing less powerful dehumidifiers for smaller crawl spaces can expect to pay less while those wanting more powerful humidifiers or those made with premium, durable materials should expect to pay more.
Ultimately, it is difficult to calculate how long it will take to dehumidify your crawl space as a result of dehumidifier efficiency changing based on the environment. For example, the Alorair 70 Pint Dehumidifier will take a full 70 pints of water out of the air every day at 90 degrees Fahrenheit and 90 percent RH, but only 35 pints per day at 80 degrees Fahrenheit and 60 percent RH. Dehumidifiers are best used for the long haul, not as a one-off.
Drainage, power supply, and crawl space accessibility will determine the best place to put a dehumidifier in your crawl space. If you have a pump, you’ll want to have the dehumidifier close enough to your discard location to reach easily. You’ll also want an outlet nearby. Finally, if possible, put the dehumidifier near an access point for easy maintenance and reachability.
Final thoughts on the best crawl space dehumidifiers
Getting a good dehumidifier for crawl space air management does not have to be tricky, even though the environment can be confusing, as we typically don’t think about the area under our house often. With the above dehumidifiers, you’ll be able to make the underbelly of your home stronger and more resistant to mold, rot, and other issues. With proper encapsulation, ventilation considerations, and possible communication with a local contractor you can reclaim your crawl space as a hygienic part of your home.
