Crawl spaces tend to retain moisture, even if you have a vent. Especially in warmer climates, hot air that collects under the home will cause condensation when it hits the air conditioning from inside the home. In general, though, crawl spaces are chilly because they are close to the ground and shielded from the sun. Moisture from the dirt can also collect there. A dehumidifier is a great tool to protect the structural integrity of your home from the damaging effects of moisture, and prevent the growth of mold and mildew that can cause breathing problems. However, it’s best to choose one that is specifically built for the space. We’ll look at the most important features of the best crawl space dehumidifier and offer our choices for the top models.
- How Dehumidifiers Work
- Features of a Crawl Space Dehumidifier
- How to Prevent Damp Crawl Spaces
- Different Types of Crawl Space Dehumidifier
- Product Comparison
- Product Reviews
- 1 AlorAir Sentinel HDi90 Dehumidifier Basement/Crawlspace Dehumidifiers 198PPD (Saturation)
- 2 Ivation 70 Pint Energy Star Dehumidifier WITH PUMP - Large
- 3 Dri-Eaz F413 Revolution LGR Dehumidifier, 12.5 inches
- 4 Frigidaire 70-Pint Dehumidifier with Effortless Humidity Control, White
- 5 Aprilaire 1850 Whole Home Pro Dehumidifier, Removes Up to 11.9 Gallons of Water/Day
- What Makes a Crawl Space Wet
- The Problem with Damp Crawl Spaces
- Where to Install Your Dehumidifier
- What Not to Do
How Dehumidifiers Work
All electric dehumidifiers extract moisture from the air in order to keep humidity levels in a safe zone. The way they work is by pulling air in through a vent, which then passes over chilled metal coils. That causes moisture in the air to condense and drip into a bucket that must be emptied occasionally. Other models are able to drain moisture out through a hose to some appropriate location, and don’t need to be emptied.
Features of a Crawl Space Dehumidifier
A crawl space dehumidifier is designed specifically to work in that environment, and far exceeds what a portable dehumidifier can do. Crawl space dehumidifier prices vary, depending on their construction. Cheaper ones are plastic and the longer-lasting metal ones are more costly. Following are the special features that distinguish this type of dehumidifier:
Design – Dehumidifiers made for a crawl space take into account the low ceiling, and tend to be long and low, rather than tall.
Construction – Crawl spaces are often cold and wet, so the dehumidifier needs to stand up to that environment. They are usually built with a steel casing rather than molded plastic for durability.
Components – The internal workings of a crawl space dehumidifier are heavier and more efficient than those inside a portable, which needs to be light enough to move around. Typical materials for the fan, motor, and coils are brass and stainless steel.
Operation – Crawl spaces are chilly, and most dehumidifiers don’t work well in cold conditions. The high-end construction of a crawl space dehumidifier helps it work effectively at temperatures way below the 65°F/18°C cutoff of a portable.
Efficiency – You don’t want your dehumidifier to have to run all the time in order to maintain an optimum 45-50% relative humidity level. That eats up a lot of electricity. A good crawl space dehumidifier will be energy efficient and able to cycle off frequently, which also preserves the overall longevity of the machine.
Cost – Unfortunately, the top quality materials and special design of these dehumidifiers come at a steeper price than do portable models. However, rest assured that the cost is still less than two or three smaller dehumidifiers that will burn out within the expected lifespan of a good crawl space model.
How to Prevent Damp Crawl Spaces
The good news is that newer building codes have design standards aimed at keeping crawl spaces as dry as possible. However, these building codes vary from place to place, and older homes are not likely to have taken them into consideration. It is also possible that mitigation features for dampness exist in your home but have deteriorated with age.
Because dampness in your crawl space can damage the property and make life uncomfortable for people inside the home, it’s important to keep on top of the humidity levels down there. A specially designed dehumidifier is your best solution if you find that your crawl space is too damp. It can be tricky to find the best dehumidifier for you, based on space and other concerns, but we’ve got a great list that is sure to make short work of the job. First we will explain a few different types of crawl space dehumidifier to help you narrow down your needs, and then get right into detailed dehumidifier reviews of individual products.
Different Types of Crawl Space Dehumidifier
There are lots of different brands and models of crawl space dehumidifier, but they all typically fit one of three categories for what is done with the water once collected.
1. Bucket model
The most common type, a bucket model dehumidifier collects moisture in a bucket which the homeowner needs to empty every so often. This can be labor intensive, and crawl spaces are not that easy to move around in, so it might not be the best choice for your needs. However, if you can position the dehumidifier in a way that allows easy access to the bucket, and feel confident in your ability to remember to check the bucket frequently, it can work.
2. Gravitational force model
This kind of dehumidifier uses gravity to push collected water through a hose and down a drain (or to a safe drainage area). Once installed, you don’t have to do anything to manage the water except for checking the connections every so often to make sure they have remained in place. However, not all homes have the right elevation and setup for this. There needs to be a drain nearby that is lower than where the dehumidifier will sit.
3. Pump model
For total ease of use, you may want a dehumidifier with pump attached. This allows the water to be pushed in any direction. It is especially useful if your drain is some distance away from the dehumidifier or needs to travel upward to reach the drain. These models tend to be the most expensive, but are worth it when you don’t have the necessary elevation difference for a gravitational system but really don’t want to hassle with emptying a bucket.
If your crawl space gets below freezing (32°F/0°C), the coils on your dehumidifier are likely to freeze over and stop working. Models with a de-icer have a special gas that keeps the coils at the optimum temperature and your dehumidifier humming along. Coils are meant to be cold, but ice will interfere with their operation and shorten their useful life.
Humidistats are gauges that read the relatively humidity in the room. This can help you to be sure at a glance that the unit is working. You can also compensate for times that are more or less damp by changing settings on the device in response to the humidistat’s reading.
|AlorAir Sentinel HDi90|
(1° - 38°C)
(10° - 40°C)
Stay with us for in-depth crawl space dehumidifier reviews.
1 AlorAir Sentinel HDi90 Dehumidifier Basement/Crawlspace Dehumidifiers 198PPD (Saturation)
An AlorAir dehumidifier with pump built in really has it all. Designed specially to work in cooler temperatures, it also has a hot gas valve defrosting system that keeps the coils from freezing. It is constructed with solid, high quality materials, advertised to be “strong as a tank.” The AlorAir features internal corrosion protection that helps to maintain the inner components in top shape – without this feature, constant exposure to moisture and the potential for Freon leakage can corrode the metals.
Inside is a heavy condensate pump and G3 filter, and the coils are epoxy coated as an extra layer of protection against moisture. AlorAir dehumidifiers are Energy Star rated and perhaps coolest of all, have the potential to be remote controlled (remote sold separately). It’s worth shelling out for the remote because it allows you to monitor your machine without having to get down into the crawl space, and provides that bonus humidistat feature.
This particular model comes with a pump for the easiest drainage of water possible. The quick connect plugs make installation fast and easy. Made to work in spaces up to 4,000 square feet, you will be thrilled with the AlorAir’s capacity to remove up to 90 pints of water per day from the air. More affordable models that can handle 55 pints per day are also available. These dehumidifiers come with a nice 5 year warranty.
- 15.8 x 24.8 x 13.8 inches
- 78.3 pounds
- 5 year warranty
- Pump makes drainage easy
- Sturdy construction
- De-icer and remote humidistat.
- Remote sold separately
- Ships from China & may sustain some damage in freight
2 Ivation 70 Pint Energy Star Dehumidifier WITH PUMP - Large
This small dehumidifier for crawl space is a more affordable unit and actually covers quite a bit of area, being able to dehumidify up to 4,500 square feet. It has a built-in 16W pump and hose that can direct water up to 16 feet vertically to drain into a sink or out a window. It is Energy Star certified with an intuitive LED display that shows humidity levels, fan speed, and various maintenance alerts. You can also run the Ivation on a timer if you like!
At just 40 pounds, mounted on casters, this dehumidifier is easy to move around. It might be ideal if you have more than one area you’d like it to tackle. For smaller or more accessible spaces, you don’t need to use the pump and hose setting but can rely on the included containment bucket instead. Used this way, the bucket has an auto-shutoff feature to protect against spills.
In the humid days of summer, reliably remove up to 70 pints of moisture from the air per day. The machine comes with a six foot long cord and washable filter. The frost sensor powers off the compressor when the coils ice over but keeps the fan running to help melt it; this model does not have a hot gas de-icing feature. It is able to restart automatically after a power outage, though, which can be a handy bonus. Two fan speeds allow for more control of your dehumidifier settings.
- 15.4 x 10.8 x 23.2 inches
- 39.7 pounds
- 1 year warranty
- Pump feature included
- Light and easy to move
- Built-in humidistat.
- Initial setup is a little bit tricky
- Plastic rather than metal construction
Hose may leak a bit at the connection point
3 Dri-Eaz F413 Revolution LGR Dehumidifier, 12.5 inches
The Dri-Eaz is another crawl space dehumidifier with pump included. This unit makes our list because it dehumidifies a really large area – 7,000 square feet – with a small frame only 12.5 inches across and 21.5 inches deep. That helps because while your crawl space may be huge, the access door for it usually is not. At 60 pounds, it is not the easiest to move around, but its compact size makes it doable. Once installed, it is easy to see if the pump is working because the included hose is clear. With water draining safely away, there’s not much you have to do. The Dri-Eaz has an automatic restart function, too, so blackouts don’t require you to get down in the crawl space to start your dehumidifier back up.
With built-in humidistat and automatic pump, the Dri-Eaz is simple to read, set, and drain. It can pull up to 80 pints of water per day and makes short work of getting your humid spaces to the desired relative humidity level, typically preferred between 35-50% for the comfort of most people. Construction and repair professionals also often choose this brand to dry out spaces that have been recently flooded.
Built tough in the USA, Dri-Eaz humidifiers feature the company’s legendary rugged rotomolded housing for durability. Owners enjoy a lifetime limited warranty on the polyethylene housing. The compressor and coils are backed for 6 years, and parts and labor are covered for one year from date of purchase.
- 12.5 x 21.5 x 12.5 inches
- 61 pounds
- 6 year warranty
- Smaller size
- Works quickly
- Includes built-in pump and hose.
- No hot gas de-icing capacity
- Hose may leak a bit at the connection point
- On the heavy side.
4 Frigidaire 70-Pint Dehumidifier with Effortless Humidity Control, White
The Frigidaire will ably pull up to 70 pints of water from the air per day and includes a digital humidity readout and a timer function. It can work in temps as low as 41° F, which may not be quite low enough if you live in a cooler climate, but certainly sufficient for the most humid months of the year in most places. It uses a 115V electrical outlet and is Energy Star rated.
This dehumidifier uses what it calls “Effortless Humidity Control” to allow users to set the exact percentage of humidity desired in the room. However, it can only be set in increments of 5%. This is a gravity model that includes a hose to drain water directly to a spot that’s lower than the unit itself. If this setup doesn’t work for you, the included 1.6 gallon containment bucket is easy enough but does require frequent emptying.
It is a solid unit, constructed of sturdy plastic that should last for many years, though shy of the lifespan expected from a metal dehumidifier. The trade-off does mean a lighter overall weight for this unit at 47 pounds. It is designed with portability in mind, including a top handle and caster wheels to make moving it from place to place a snap. This Frigidaire dehumidifier warranty covers everything for one year, but also guarantees the compressor, condenser, and other internal components for five years.
- 11.6 x 15 x 24.4 inches
- 47 pounds
- 1 year full warranty; five years on compressor and condenser
- Includes drainage hose
- Easy to move around
- Digital humidity readout.
- No hot gas de-icing capacity
- No pump; gravity drained
- Gets warm upon use.
5 Aprilaire 1850 Whole Home Pro Dehumidifier, Removes Up to 11.9 Gallons of Water/Day
Built strong to dehumidify spaces up to 5,200 square feet, the Aprilaire has corrosion resistant aluminum coils and no messy trays to empty. It uses gravity to drain water instead. This model also has the ability to connect to the ductwork in your home if you would like it to dehumidify the whole house, rather than just the crawl space. It pulls an impressive 95 pints of water from the air per day.
The control panel may be mounted on the side or top of the unit, so it is easily accessible within the tight confines of a crawl space, whether reached from the side of the house or through a trap door. It is low maintenance, needing only to have the filter changed or cleaned once per year. Made in the USA, this product comes with a five year warranty.
- 33 x 13 x 16 inches
- 70 pounds
- 5 year warranty
- Pulls 95 pints per day
- Can attach to ductwork
- Control panel can be mounted on side or top.
- No hot gas de-icing capacity
- No pump; gravity drained
- Doesn’t work below 50F.
What Makes a Crawl Space Wet
Crawl spaces are typically found in homes without a basement. They are only tall enough for a person to crawl around inside, not stand, hence the name. The surface of a crawl space is most often plain dirt instead of concrete. The reason crawl spaces exist at all is to keep the main structure of the home away from ground and rain water and make it harder for pests like insects and rodents to move in.
A crawl space is also a good location for some of the home’s important but unattractive systems, including electricity, HVAC (air conditioning and heat), and plumbing. And finally, if there’s any room left, homeowners can store seasonal items there without taking up space inside the home.
Usually, crawl spaces are accessed by humans through a trap door in the floor above or via a small door on the side of the house. Water, on the other hand, can get in by any number of means – and it does. The dirt floor contains moisture which can evaporate directly into the air in the crawl space. Soil is also a source of mold and fungal spores which love to multiply in a damp environment. Heavy rains around the house tend to flow to the lowest point, which is often the crawl space. And any temperature differential between the crawl space and the home above will cause the damp air to condense and collect on beams and the underside of your floor.
The Problem with Damp Crawl Spaces
A crawl space with too much humidity is a problem for two main reasons. First, excess moisture forms a breeding ground for mold, mildew, and fungus, which will cling to any exposed surface. This growth will damage anything it grows on, including the structural elements of your home, the heating, cooling, and plumbing systems located there, and any personal items stored in the crawl space. Water itself is also quite damaging.
Second, the presence of moisture is likely to set off a chain reaction that has ever larger pests invading your home. Insects like to eat mold, but many don’t stop there and can chew holes through wood, as well. Larger critters such as mice and rats will be attracted to the area because they like to eat insects.
So now we have a crawl space teeming with mold, mildew, bugs, and rodents, including feces from the animals, dust mites, and other gross stuff. Will it all eventually move into the home? Yes, it will! Air tends to warm as it rises, especially under the effects of a heating system or even the sun baking the outside of the home. That warm air will continue to rise through numerous tiny cracks right into your home, bringing mold and fecal spores right along with it. It is also common for pest infestations that began in a crawl space to outgrow the available resources, driving them inside in the search for more food.
This side effect of a damp crawl space is bad for both health and comfort, especially if any residents have allergies, respiratory disorders, or compromised immune systems.
Where to Install Your Dehumidifier
The best positioning for a crawl space dehumidifier is as close as possible to the center of the area. Tucked away in a corner, the unit may struggle to dehumidify the entire space. Make certain it is at least six inches away from any wall or ceiling to avoid blocking the air vents. A tip to keep your dehumidifier in good working order for a long time is to vacuum up as much dust, cobwebs, and debris as possible before installation. Obviously you won’t be able to vacuum a dirt floor, but you can lay down a piece of plywood to make the surface on which the unit will sit as level as possible. Blocked vents will cause the machine to struggle, work inefficiently, and ultimately burn out more quickly.
What Not to Do
You may be tempted to run a vent fan in your crawl space in order to circulate air. However, in homes with air conditioning, a fan can actually cause moisture to build up in your crawl space. That cold conditioned air sinks and makes its way into the crawl space, which is then a few degrees colder than the outside air. A vent fan will bring in hot air from outside. When it hits the cooler air in the crawl space, condensation forms and builds up on all available surfaces. Your dehumidifier may not be able to keep up, and corrosion, mold, and mildew are possible results.
We hope we have given you the information you need to make an informed purchase of the best dehumidifier for crawl space that meets the needs of your home. Not only does a drier environment keep the structure in top shape much longer, avoiding costly repairs, it also prevents the kind of mold and mildew growth that can make respiratory conditions much worse. Whether you choose a more affordable plastic model that may need to be replaced a few times, or a sturdier and longer lasting metal machine, the result is a healthier environment within your home, which is priceless.