Dehumidifier for Crawl Space

D o you lack ventilation in the crawl space, or it is ventilated yet you keep on encountering condensation build-up? Beware that this is an issue you must tend to immediately as you risk for the hot air underneath the house to cause moisture when it hits the air indoors, creating a prosperous growing ground for mold and mildew, two unwanted “guests” that can take a toll on your health. If you live in a warm climate area it is all the more imperious to tend to this issue as chances are higher for excess moisture to form. By this point, you are probably aware of the existence of dehumidifiers, which are appliances that are specifically designed to remove excess moisture and normalize humidity levels indoors. For crawlways, there are specially designed dehumidifiers that can handle the removal of higher amounts of moisture than their classic counterparts.

Top 5 Crawl Space Dehumidifiers Compared

Photo Product Design Water Extraction Area Coverage Adjustable Humidistat Highlight Warranty Price

Best Overall
1. Dri-Eaz F515 PHD 200 Size: 21.5” x 17.6” x 12.5″
Weight: 63.2 lbs.
Housing: Polyethylene
135 pints per day 1000 square feet Auto-restart function Housing: Lifetime
Coil and compressor: 6 years
Parts and labor: 1 year
2. Dri-Eaz F413 Revolution Size: 21.5” x 17.6” x 12.5”
Weight: 65 lbs.
Housing: Polyethylene
135 pints per day 7000 square feet Touch-Pad Controls Housing: Lifetime
Coil and compressor: 6 years
Parts and labor: 1 year

Our Choice
3. AlorAir Sentinel HDi90 Size: 23.2” x 15.2” x 17.7”
Weight: 78.3 lbs.
198 pints per day 2600 square feet Energy Star certified Parts and labor: 5 years
4. Aprilaire 1850F Size: 27.5” x 14.5” x 12.5”
Weight: 70 lbs.
95 pints per day 3000 square feet MERV-8 air filter Parts and labor: 5 years
5. Ebac CD30E Size: 22” x 14” x 12”
Weight: 55 lbs.
17 pints per day 400 square feet Low-temperature operation Compressor, evaporator, and condenser: 3 years
Parts and labor: 1 year

1. Dri-Eaz F515 PHD 200

Even though it is a costly upfront investment, it is one worth making considering the overall performance it brings to the table. With the F515, mold and mildew will never be present in your home as proper moisture levels will be kept as long as you run it. It measures 12.5 inches in width, 17.6 inches in height, and 21.5 inches in depth, this compact design making it easy to install, maneuver, and ensuring maximum space efficiency. It weighs only 63.2 pounds, so you won’t need a second person when handling it. Furthermore, the housing is made with quality, impact-resistant rotomolded polyethylene that ensures durability as the years pass.


Its maximum water extraction capability reaches 135 pints per day, so regardless of how high humidity-related issues are, using it is a surefire way to fix them. However, this is the optimal performance we are talking about, on average, when placed in an area where the temperature sits at 80 degrees Fahrenheit and relative humidity at 60%, being able to collect up to 75 pints of moisture per day. What further enchants is the 1000 square feet of 7000 cubic feet area coverage that ensures humidity will sit at proper levels throughout your entire house.

F515 Specifications
Air movement:
180 CFM
6.2 amps, 115V
Refrigerant type:
Fan speeds:
  • Automatic pump out: This is the feature that allows a continuous operation of the unit as draining is not required on your part, being done automatically as moisture is collected.
  • Digital touch-pad controls: Provide an intuitive use of the unit, 4 different language options being put at your disposal. Furthermore, it displays inlet and outlet temperature and relative humidity in real time.
  • Auto-restart: In the event of a power outage, when the power comes back, the unit will retake its operation with the previously selected settings so that you won’t manually have to insert them again.
  • Automatic defrost: This feature allows you to use it even in chilly spaces as it tends to the defrost of the coils so that ice build-up does not form.
Other Mention Worthy Details
  • It can operate within temperatures ranging from 45 to 100 degrees Fahrenheit.
  • Comes with a 20-foot long drain hose which allows quick-connect fitting.
  • Detachable power cord measures 6 feet in length, eliminating the need for extension cords.
  • The product is ETL listed to comply with CSA safety standards.
#1 – It does not operate:
Cause Solution
It is not turned on Turn it on.
It does not receive power Plug it in and check the connection of the power cord at the outlet and at the base of the unit.
#2 – Room is not dry:
Cause Solution
Insufficient drying time Allow the unit more time to operate.
Poor air circulation Use air movers to increase air circulation.
Excessive moisture infiltration Prevent infiltration by sealing off the area.
#3 – Collects small amount of water:
Cause Solution
Clogged filter Check filter and clean or replace it as necessary.
Clogged coils Check coils and clean them as necessary.
Low temperature indoors Increase room temperature as levels have gone below what the unit can handle.
#4 – Water drips when moving it:
Cause Solution
It was unplugged before it finished purging Wait until the defrost cycle finishes before you unplug it.

As it reigns over competitors, a hearty warranty was expectable as well. Thus, the lifetime backing provided by the manufacturing company for the housing, alongside the 6 years which cover the coils and compressor, and the first year when parts and labor are covered by the agreement come as no surprise. On top of that, as Dri-Eaz is one of the largest manufacturers out there, folks working at customer support are true professionals who treat their clients respectfully and promptly fix any issues involved with the products sold by the company.

2. Dri-Eaz F413 Revolution

Gone are the days of bulky moisture removal devices as higher efficiency and more compact units like the Revolution keep popping out. Able to remove up to 80 pints of moisture per day in an area where the temperature sits at 80 degrees Fahrenheit and the relative humidity at 60%, and up to 139 pints of moisture per day in almost saturated conditions, all while processing up to 180 cubic feet of air per minute, you can trustfully rely on it to solve indoor humidity problems and keep mold and mildew at bay.

Needless to say considering the fact that it comes from the top brand on the market, it allows full adjustability of its operation so that you may receive expected results. It features an onboard humidistat that lets you pick the humidity level to be reached and maintained, and there is the option of running it continuously.

It is intended for spaces of up to 7000 square feet, which greatly exceeds industry standard and it can handle operating in spaces where temperatures reach levels as low as 33 degrees Fahrenheit without the coils freezing up. It features recessed feet that allow easy and convenient transport, and an electronic control panel which displays relative humidity, inlet and outlet temperatures, and keeps track of operating hours. Additionally, the company backs the housing for a lifetime, the coils and the compressor for an impressive 6 years, and it provides a 1-year warranty on parts and labor as well.

F413 Specs
Air movement 180 CFM
Energy factor 2.21 L/kWh
Maximum wattage 713W
Lowest operating temperature 33 degrees Fahrenheit
Control panel Electronic
Drain hose length 40 feet
Power cord length 25 feet

3. AlorAir Sentinel HDi90

For alarmingly high indoor humidity levels, the proper way to bring them down and ensure a mold-free, healthy living space is to use the HDi90 as it delivers an unparalleled 198 pints per day moisture extraction at maximum saturation. On average, it is able to remove up to 90 pints per day in an area where the temperature sits at 80 degrees Fahrenheit and the relative humidity at 60%.

It can cover areas of up to 2600 square feet, providing excellent performance as long as relative humidity ranges from 35 to 95%, and the temperature spans from 33.8 to 104 degrees Fahrenheit. As it can handle operating in low-temperature environments, use in the crawl space and basement is viable without worrying that ice might build up on the coils or compressor.

It features epoxy coated coils that have a long lifespan, ensuring durability even in corrosive environments. It is as energy efficient as these devices get, proof enough being the fact that it is Energy Star certified, boasting a factor of 2.88 liters per kWh. A quick and efficient clearing of ice is granted by the “hot gas” defrosting system it features. When it comes to backing, the manufacturing company has it covered against defects for 5 years since the date of purchase.

Sentinel HDi90 Specs
Air movement 210 CFM
Energy factor 2.88 L/kWh
Energy Star certified
Functioning temperature range 33.8 – 104°F
Functioning humidity range 35 – 95%
Maximum noise level 55 dB

4. Aprilaire 1850F

With numerous convenience features that add to the delight of using it under its belt, the 1850F is one of the most versatile entries in the niche. It features a MERV-8 filter helps remove dust particles and allergens from the air, creating a safer habitat for you to live in. When it comes to its main purpose, as it is able to remove up to 95 pints of moisture per day without flinching and due to the wide 3000 square feet area coverage, it is sure to handle any environment you place it in.

It features a defrost function that automatically activates when there are dangerously cold conditions in order to keep the compressor safe from damage. As it can operate in areas where the relative humidity spans from 0 to 100% and the temperature ranges from 50 to 104 degrees Fahrenheit, you can even use it in the basement.

For convenience purposes, it comes with lifting handles and easy-roll locking wheels that enable you to move it from one area to another without much effort. The manual control dial it features allows you to toggle between humidity levels with ease so that you may create the ideal ambiance for you. In addition, it is one of the quietest models out there, the maximum sound level it reaches being only 54 decibels.

1850F Specs
Air movement 245 CFM
Energy factor 1.88 L/kWh
Functioning temperature range 50 – 104°F
Functioning humidity range 0 – 100%
Maximum noise level 54 dB
Refrigerant R-410A

5. Ebac CD30E

If the previously reviewed products deliver a higher moisture removal performance than you need, the CD30E is your optimal choice. It can remove up to 17 pints of moisture per day, and it is designed to cover spaces of up to 400 square feet. It comes at a much more reasonable price than the models which outrank it, so it is a more budget-smart option.

The drain hose it comes with measures 9.8 feet in length. It can handle operating in an environment where the temperature spans from 33 to 95 degrees Fahrenheit, which ensures you won’t have to worry about frost buildup. Speaking of, a feature that helps keep ice from forming on the internal parts of the unit is the “hot gas” defrost that automatically melts away frost as it starts building. Another convenient feature is the automatic restart that, in the event of a power outage, will resume operation from where it left off without requiring any manual input on your part.

As it produces a maximum operating noise of only 47 decibels, you won’t even notice that it is turned on. furthermore, the manufacturing company backs the condenser, compressor, and evaporator against defects for 3 years, and during the first year after you make the purchase, it covers parts and labor free of charge as well.

CD30E Specs
Air movement 170 CFM
Maximum wattage 510W
Functioning temperature range 33 – 95°F
Drain hose length 9.8 feet
Maximum noise level 47 dB
Refrigerant R-134A

Causes and Effects of High Moisture

High Humidity Sources

Vented or not, there’s one thing all crawlways have in common, which is excess moisture problems. But why is this a common issue, and why are southern areas especially affected by it? To understand how humidity builds up underneath the house, you have to take knowledge of the sources that cause it, obviously.


Soil iconSoil:

One of the most common sources of excess moisture is uncovered soil. If there are no vapor barriers put down on the ground, the soil will constantly evaporate water into the crawlway, causing excessive dampness in the air.



Plumbing leak iconPlumbing leaks:

A lot of plumbing pipes, whether it is drain lines or supply lines, actually run through the crawlways, which means that when a leak occurs in the pipes, this space gets filled with water which inevitably evaporates and turns into humidity. Seeing how you rarely visit this area, chances are for leaks to go on for weeks, even months before they are discovered.



Wall iconFoundation walls:

As few people damp-proof the exterior of the house, moisture migrates through the foundation of the walls. Thus, whenever it rains or if the ground is generally moist due to environmental conditions, it’s likely for it to infiltrate through the walls and cause excess humidity.



Vent iconFoundation vents:

The idea behind vents might be to dry out the crawlway, but, as a matter of fact, this actually causes the exact opposite, especially in summer as the outdoor air, which is high in moisture, gets through the vents and raises relative humidity in the crawl space.


Health Risks

How internal temperature regulation works:

Naturally, when the human body starts to heat up, sweat is released, which is often evaporated from the skin, helping us cool off in return. When environmental conditions do not meet expectations as there is high moisture content in the air, the sweat is not able to evaporate, remaining in the body feeling sticky and hot. This causes the body to work even harder to cool off, which results in excessive sweating, heavy breathing, and an increased heart rate. As you sweat excessively, a major loss of water and chemicals occurs, which causes the body to cease functioning properly.

Influence on the Structural Integrity of the House

Aside from threatening your health directly, unchecked humidity levels can affect the structural integrity of your home as well. Often overlooked and not on the top of homeowner’s priority list, the crawlway accumulates dangerously high moisture quicker than you would expect. Those living in generally humid areas have to look out for this especially as mold infiltrations occur easily when humidity is left unmonitored. Otherwise, they risk investing a lot more money on repairs than they would have spent on a simple specialty dehumidification device.



As humidity in the crawlway rises, it can build up in the walls, causing them to become soggy. Over time, this leads to a decrease in structural safety, existing the potential risk of aggressive cracking and even complete wall destruction at a slight impulse. Besides using a moisture removal device, we recommend that you increase wall insulation to enhance your house’s resistance.



When mold and mildew get into wood flooring, they are not only extremely hard to get rid of, but can cause permanent destruction which asks for a replacement. If mold has made its way into your flooring, we recommend that you use a tri-sodium phosphate solution that thoroughly rinse, and let the floor dry out on its own.


Mechanical systems:

High humidity goes hand in hand with condensation, and if you don’t keep moisture levels in check, condensation can build up on water pipes, which will ultimately cause them to rust and burst. This will imply huge repair costs and significant damage to the structure of the house, so it’s best for you to try and avoid the occurrence altogether through any means necessary.



Just as flooring, wood furniture is highly vulnerable to condensation and mold/mildew infiltration. Woefully, furniture cannot always be saved if this issue emerges, so you must ponder at the possibility of facing costly redecorations if you do not take proper safety measures and take care of your home as a whole.

How We Tested

Humidity removal

Obviously, this was the first testing trial we put our selections through as it indicates how well the devices will perform in high humidity conditions and how fast they will help normalize moisture levels. We first used a humidistat to establish the initial moistness of the air, and let the device run for 8 hours so that it had enough time to wick excess humidity. Afterward, we shut it off and tested humidity levels again to see how big of a difference was made towards lowering moisture in the air.

Low-temperature operation

The crawlway is usually a cold space, so it is essential for the dehumidifier to handle operating in low-temperature conditions. To test and see performance delivery under harsh conditions which are typical for the environment underneath the house, we kept a steady temperature of 40 degrees Fahrenheit and checked how each product performed. Afterward, we raised the temperature by 20 degrees and checked moisture removal performance again, comparing results to see if there were any fluctuations in the harsher environment.

Ease of use

As we were running the testing trials we previously discussed, we also paid attention to ease of use. No one likes handling a device that is above their pay grade when it comes to operational familiarity, and knowing this, we made sure to look into how intuitive humidity level adjustability and the overall operational customization was.

Noise level

Even if it is placed in the crawlway, the appliance can still become quite a nuisance for you if you don’t check out how loud it gets when it operates, bothering you when you are trying to relax or do household activities. Thus, to make sure that you won’t be discomforted by the addition of any of our picks in your home, we checked their noise output ourselves. For this trial, we tested the products one by one, using a decibel meter that we placed approximately 1 foot away from the device to see what is the operational noise level.

Test results

Product Humidity removal Low temperature operation Ease of use Noise level
F515 PHD 200 10/10 10/10 10/10 10/10
F413 Revolution 10/10 10/10 10/10 9/10
Sentinel HDi90 10/10 9/10 10/10 8/10
1850F 9/10 9/10 9/10 8/10
CD30E 7/10 10/10 8/10 10/10

Customer Feedback

Let’s have a look at some of the online comments left by customers who have already tested out these products. Getting a look at the first-hand experience of another user is one of the best ways to figure out not only how qualitative a product really is, but to more better understand whether it is the right choice for you or not.

Positive reviews: Negative reviews:
  • ”It’s solidly built and I especially like the compact design.”
  • ”It pulled about 5 gallons of water over a few days, really impressive.”
  • ”Working great so far after 4 months, controls are easy to use and it is easy to read in darkness.”
  • ”It reduced the humidity from 72% to 50% in only 2 hours.”
  • ”Digital readout is really nice, and so is the quiet operation.”
  • ”I previously owned another Dri-Eaz dehumidifier, it failed me after 2 and a half years. Hope this one won’t have the same fate the last one did, because these things are really expensive.”
Positive reviews: Negative reviews:
  • ”Drain line is long enough to lead outside, no more emptying on my part.”
  • ”Good digital interface, really makes a difference in its ease of use.”
  • ”It performed admirably in the 5 months since I have it, humidity hasn’t exceeded 50% ever since.”
  • ”Small enough to perfectly fit my tight crawlway.”
  • ”It starts working when needed, and turns off when humidity is at the right level, really like this automatic operation.”
  • ”The water disposal function is poor, it leaks.”
Positive reviews: Negative reviews:
  • ”It took little time to install it, and comfort levels are way better since I have it.”
  • ”Cycles on and off just fine on its own to keep my desired 50% humidity.”
  • ”Works as advertised! Really impressed by it, it’s the sixth dehumidifier I had up to this point, and the best, by far.”
  • ”Quieter than I expected, right now I’m considering using it in the basement as well.”
  • ”Worked during winter as well, unlike the one I previously owned that was unusable when temperatures dropped too low.”
  • ”Its operation kind of dropped in quality when temperatures went below 55 degrees.”
Positive reviews: Negative reviews:
  • ”The cord is very long, which I like as I didn’t have any outlets for plugging in the immediate proximity.”
  • ”Easy to operate and install, did the whole procedure on my own.”
  • ”I like the smart design, its epoxy-covered coils prevent corrosion, which not a lot of dehumidifiers deliver.”
  • ”I use it for the basement, made a huge difference in dampness and the awful smell in the basement is completely gone now.”
  • ”Helped drop humidity from 80% to 70% in only a few hours after installing it.”
  • ”It’s very expensive, sure, it might work great, but the initial cost is a bit too exuberant.”
Positive reviews: Negative reviews:
  • ”Quiet and effective, didn’t expect it to do so great considering that it’s considerably cheaper than most dehumidifiers in its category.”
  • ”Have had it for 5 months now, dampness hasn’t been an issue since then.”
  • ”It impacts humidity in the house as well, which is great as now we don’t need to buy a device separately for our usually damp kitchen.”
  • ”I ran mine for over 6000 hours, besides the occasional cleaning with compressed air, it didn’t require my attention at all.”
  • ”Compact size made it easy to get the device through my small crawlway access door.”
  • ”A bit disappointed as it didn’t really do well for me, but I should have bought one that can remove a bigger amount of humidity as the 17 pints it provides don’t suffice for my issues.”

It’s natural to be forgetful when it comes to the crawlway as it is an area you don’t need to access for other reasons, like the basement say for example. However, as you already understood by this point, maintaining proper humidity levels in this area is just as important as it is in the rest of your home as it the environmental conditions you keep in it influence the habitable area of the house as well. To put it in simpler words, if humidity is high in the area underneath your home, it will inevitably be high indoors as well. Furthermore, there’s the issue of moisture rising and affecting the structural integrity of your home, which puts your safety in danger directly and could end up costing you a hearty sum of money on repairs.

Although we recommend all of our selections, we must admit that some models do better from certain points of view than others. For example, if your crawlway is very large, we would advise you to opt for the Dri-Eaz F413 Revolution which covers areas of up to 7000 square feet without dropping in performance. However, if it is extremely damp and gets this way fast, your best option would be the AlorAir Sentinel HDi90 as its maximum moisture removal capacity is an impressive 198 pints per day. When it comes to overall excellence in design and performance, the obvious pick is our number 1 ranked choice, the Dri-Eaz F515 PHD 200 that perfectly balances everything you need from a crawl space dehumidifier.

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