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Crawl Space Dehumidifier Without Encapsulation | Is It Pointless?

When researching encapsulation, it is often highly recommended to have a dehumidifier installed in conjunction with encapsulation. If the concern is humidity in your crawl space, you would think that it would make sense if just a crawl space dehumidifier was installed, even without the encapsulation. After all, full encapsulation has significant cons along with its pros. However, professionals tend to disagree. 

To learn about why a dehumidifier is often not enough in a crawl space, in what situations it can possibly work without encapsulation, as well as what to consider before buying a crawl space dehumidifier, read on.

The professional consensus is that a crawl space dehumidifier without encapsulation is pointless. Alone, it can’t cope with significant amount of water, which is often present in crawl spaces. However, if you live in a drier climate or pair the dehumidifier with a vapor barrier and sump pump, it may work.

Consensus Is That It Is Pointless

Any source you ask, whether you are searching online or asking a professional, will say that having a dehumidifier in your crawl space without encapsulation is absolutely pointless. 

Reasons for This Opinion

When encapsulation is installed in your crawl space, it acts to prevent moisture from infiltrating your crawl space. 

A dehumidifier acts as an emergency measure of sorts. If the encapsulation cannot keep all of the moisture out of the crawl space because of excessive moisture, the dehumidifier does its work to take care of the water that does infiltrate the crawl space. 

Furthermore, should any of your water pipes spring a gentle leak, then the dehumidifier can help to prevent this from becoming an issue until you can fix it.

If your system consists of only a dehumidifier and not even a sump pump, moisture cannot be removed from your crawl space quickly enough. 

Without encapsulation, water is free to enter the crawl space and can do so very easily. Without drainage through the sump pump, standing water can accumulate in the crawl space, particularly if there is a leak in the pipes in the crawl space. 

In these conditions, the dehumidifier has to take care of high humidity levels, possibly accumulated water, and water that is consistently entering through the soil. Crawl space dehumidifiers are not suited for these tasks. 

Firstly, they are only designed to tackle humidity in the air. They cannot get rid of water that has formed puddles. If water accumulates enough that there are puddles or if water is dripping, a crawl space dehumidifier cannot help with this. 

Crawl space dehumidifiers can help prevent mold and mildew, but once mold and mildew have formed, dehumidifiers cannot stop their spread.

Even worse, once mold and mildew have accumulated, a dehumidifier can spread their spores across the crawl space and even into your home because the space is not isolated from the home.

Caveat: There Are Some Factors to Consider

It is possible that a dehumidifier in your crawl space can do a fairly good job of limiting humidity. In order for this to be true, though, there are some factors that need to be considered and evaluated. 


Depending on if the climate you live in is dry enough, a dehumidifier might be just enough to manage the air quality of your crawl space. 

This would mean that your area stays relatively warm throughout the year since humidity isn’t just naturally occurring, but it can also occur through heating. 

Having your heating on for a prolonged amount of time can cause humidity to accumulate in your home and potentially your crawl space. 

Your local climate must also have little to no risk of flooding since standing water cannot be removed by a dehumidifier. Limited rainfall would also factor into this. 

If all of these factors apply to your location, just having a dehumidifier in your crawl space could do the job. It is important to monitor the crawl space to ensure that water is not leaking and that there is no standing water.

If the humidity measured when the dehumidifier is installed is less than it had been beforehand, then the dehumidifier is doing its job, and encapsulation is not needed.

Crawl Space Ventilated?

Although ventilation is not the most efficient remover of humidity, it can do a fairly good job of removing moist air from the crawl space. 

Ventilation in crawl spaces is often required by building codes as well as encouraged by builders. Removing stale air from any part of your home is a must, even in your crawl space.

They are especially important in the summer when the air is more humid. Stagnant air is removed from the crawl space along with its humidity and expelled. This can prevent mildew and mold. 

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Vents are often closed in the winter, though, to prevent freezing in the pipes. This means that any rises in humidity cannot be helped by ventilation and the removal of moisture would be entirely up to the dehumidifier. 

Ventilation is not designed to specifically reduce humidity and, like dehumidifiers, they cannot aid in removing standing or dripping water in your crawl space. 

The bottom line is that ventilation can certainly aid a dehumidifier in removing stale and humid air from the crawl space, but it won’t help much. 

Do You Have a Vapor Barrier?

Vapor barriers installed correctly do not require a dehumidifier because of their effectiveness at keeping moisture out of the crawl space. That being said, a vapor barrier installation with the aid of a dehumidifier (even if the dehumidifier wouldn’t exactly be necessary) would be effective at limiting moisture in your crawl space. 

Vapor barriers involve the use of thick sheets of plastic to seal off the floor of your crawl space, which is often dirt or gravel. Dirt, gravel, or even concrete floors of crawl spaces can easily let water through, which is why sealing the floor is important. 

Vapor barriers can stave off humidity as well as prevent water from accumulating in puddles. Since dehumidifiers cannot aid it in getting rid of dripping or standing water, vapor barriers make their job much easier. 

Since vapor barriers are not as effective as encapsulation, it is possible that the dehumidifier might prove its use if the vapor barrier is not controlling humidity as well as it should. 

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Is an Effective Drainage System Installed?

It has been mentioned a few times in this article that dehumidifiers are useless in the case of puddles accumulating and when water is leaking or dripping. When this pooling has a way to be removed, dehumidifiers may just do the job. 

A drainage system that collects water and pumps it away by the sump pump (which is often used in the encapsulation of crawl spaces) would be a fast and simple way of removing water that the dehumidifier can’t take care of. 

basement drainage by a sump pump

If the dehumidifier takes care of the water in the air and the drainage system takes care of the rest, then the air quality of your crawl space could be managed by these two processes and without encapsulation, potentially. This system is not foolproof, though.

Accumulated water can soak the wood, and the moisture in the wood cannot be removed by the drainage system. The dehumidifier may be able to aid with this, but it might take a while for the wood to completely dry, and if the wood keeps getting dripped on, this will lead to problems. 

Wet wood is subject to rotting, mold, mildew, and termite infestation. It also is structurally weakened when it is wet for long periods of time, which could damage the structural integrity of the foundation of your home. 

As long as water isn’t consistently pooling in your crawl space, a drainage system paired with a dehumidifier may do the job, but it is essential to monitor the situation. 

Type of Dehumidifier

It is essential that the dehumidifier you use is a crawl space dehumidifier. A regular dehumidifier cannot function in a crawl space

Regular Dehumidifiers Are Insufficient for Crawl Spaces

Regular dehumidifiers are not suitable for use in the crawl space under a house simply because their capabilities are insufficient. The dehumidifying capacity of regular dehumidifiers is significantly less than crawl space humidifiers.

Crawl space humidifiers have a much higher capacity for moisture removal. Some models are capable of removing as much as 17 gallons (65 L) of moisture per day from an area spanning over 7000 ft2 (650 m2).

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By contrast, regular home dehumidifiers are only capable of removing around 2.6 gallons (10 L) of moisture per day from a normal-sized bedroom.

These figures vividly show us that regular dehumidifiers are not suitable for use in crawl spaces, as they will not remove enough moisture from the area to prevent the damage that high levels of humidity can cause.

Crawl Spaces Are Too Harsh for Normal Dehumidifiers

Regular home dehumidifiers are designed to be indoors and usually in rooms such as bedrooms that are particularly shielded from more extreme environmental factors like excessive heat or cold. As such, these devices are not particularly rugged, nor are they designed for use in harsh environments.

The design features specifications of regular dehumidifiers mean that they will be damaged beyond repair if they are used in the tough environment of the crawl space for any length of time.

However, commercial or crawl space dehumidifiers are built for continual use in the very harsh environment of the crawl space.

These machines are designed with rugged exteriors, waterproof technology, hard-wearing mechanical and electrical components, and they are built from much stronger materials than the standard plastics of regular dehumidifiers.

Crawl space dehumidifiers are designed to withstand harsh environments for long periods, while a regular dehumidifier in the same conditions will only last for a fraction of its intended lifespan in the same conditions. 

Regular Dehumidifiers Not Designed for Constant Use

Any dehumidifier that is used in the crawl space of a house must run continuously to be at all effective. The levels of humidity in a crawl space rise so rapidly that the dehumidifier used in this area must be left running at all times to reduce the humidity in the space.

Regular dehumidifiers are not designed for constant use. Even indoors, regular dehumidifiers can not handle long periods of constant use. Most of these devices are equipped with an automatic shut-off function to prevent the potential damage caused by prolonged use. 

The components of regular dehumidifiers will wear out very quickly if used continuously.

In comparison, crawl space dehumidifiers are designed to run continuously, even in the harsh crawl space. The components of these machines, such as the pump, the motor, and the electrical components are built to be durable and hardy enough to withstand constant use without sustaining damage or wearing out too quickly.

Requirements for a Crawl Space Dehumidifier

Crawl space dehumidifiers are unlike other types of dehumidifiers. As I noted above these machines must be able to withstand long periods of use within the crawl space under a house, which requires them to be exceedingly tough when compared to other dehumidifiers.

These units must have rugged external housing that is durable enough to withstand the harsh environment of the crawl space without tarnishing, rusting, or breaking down in any way.

Commercial dehumidifiers must be capable of removing very large quantities of moisture from the crawl space, at least ±9 gallons (35 L) of water per day.

These machines should also be compact enough to fit comfortably within the crawl space and to be placed in any area of the crawl space to be as effective as possible. These units should also be equipped with either a very large collection tank or the ability to pump water out from the crawl space.

A high-capacity pump and motor and heavy-duty filters are also requirements for dehumidifiers of this type.

Some extra features that many modern crawl space dehumidifiers are equipped with include:

  • Defrosting systems.
  • Adjustable wheels.
  • Remote control.
  • Digital touch screen control panel.
  • Auto-restart capabilities.
  • Temperature readout.
  • Lightweight design.

Some of the best modern crawl space dehumidifiers with these features include:

What You Can Afford

If the main reason that you are not encapsulating your crawl space and instead relying on a dehumidifier is for monetary reasons, then there are a few factors to consider. 

  • Encapsulation is a fairly expensive process since a large amount of square footage of plastic is needed as well as a dehumidifier and sump pump. 
  • A dehumidifier by itself can do the job if your local climate is permitting as well as if you have a drainage system as well as ventilation in your crawl space. 
  • If your crawl space is routinely checked up on without leaks, an infestation of mold or pests, or standing water, then going without encapsulation might just work for you. 
  • If your dehumidifier is not controlling humidity enough or if water is accumulating, it might be best to invest in a vapor barrier in your crawl space. This is less expensive than encapsulation and is less work.

Your Commitment to Maintenance

Wooden clipboard isolated on white background, good

If you choose to keep your crawl space unencapsulated, it is important to routinely check up on the area and do maintenance to keep the crawl space air quality healthy.

Routine maintenance that would have to be done include leak repairs, mold and mildew removal, pest control, and removal of standing water. None of these tasks are easy and can take a good amount of time to do.

These routine checks would have to be done fairly often, at least more often than you’d have to for an encapsulated crawl space. 

If you are at peace with this added work, then using solely a dehumidifier in your crawl space will work just fine. 

Final Verdict

Choosing whether installing a crawl space dehumidifier without encapsulation is right for you depends on a variety of factors. Adequate ventilation, a drainage system, and a dry climate can make it possible to just have a dehumidifier in your crawl space as an alternative to encapsulation

A budget can also severely limit your choices and make it so that a dehumidifier might be all you can afford. In this scenario, it’s important to know the maintenance required for just a dehumidifier, since mold, pest, and water issues may arise. 

Either way, although professionals say that having a dehumidifier without encapsulation is pointless, there are ways to make it work for you. 


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