I’ll be using this article to tell you all you need to know about using dehumidifiers in your crawl space.

Keep reading!

Dehumidifier For Crawl Space

Just like basements, crawl spaces are also prone to humidity, and as we all know, humid and unventilated areas can lead to the growth of dangerous mold.

The problem with mold (even if they aren’t physically visible) is that they produce musty smells and are toxic, as well as allergenic.

Thankfully, there is a means by which crawl space humidity can be eliminated – A dehumidifier!

This is a medium-sized tool that can play a key role in the control of moisture in your crawl space.

When Do You Need A Crawl Space Dehumidifier?

Dehumidifiers serve one purpose, and that’s to control humidity levels in a space. So you’re probably asking yourself some questions as you consider buying and installing one.

Is there humidity in your crawls space? Or is the moisture level high due to flooding or leakages?

If the answer is yes, then your crawl space is experiencing high humidity and a dehumidifier will come in handy. However, if there is little to no moisture in your crawl space, then you may not need one. At least not at the moment.

However, for the fact that you’re reading this article, I can safely assume that you’re experiencing humidity problems in your crawl space and you understand the problems that are associated with too much moisture.

For this reason, you wouldn’t want excess moisture or humidity in your crawl space, as it can damage your subfloor, floor joists, ductwork, insulation, furnace, and other vital components located beneath your building.

Another problem with having excess moisture in your crawl space is that it attracts several types of pests. These include mice, rats, insects, and other animals like raccoons.

To add to that, mold and mildew growth are common in humid crawl spaces, and they both pose a threat to human health.

If you are aware of the dangers that come with high crawl space humidity, then you would be wise to have a dehumidifier around. You may not need it right away, but you will sooner or later.

Common Signs Of High Crawl Space Humidity Levels

Before you kick in your dehumidifier, you need to be able to identify the signs that show your crawl space actually has high levels of humidity.

Here are a few pointers –

Musty odors: Musty odors are a testament to mold growth, and mold can only grow in areas that have high humidity levels. So, regardless of whether you can physically see the mold or not, the odor will tell you that the area is moist.

Visible mold: While musty odors can make you suspect mold growth, physically seeing the mold is more than enough evidence that there is high humidity in your crawl space.

Flooding: Plumbing issues and heavy rains can leave your crawl space flooded. And pools of water only mean that the area is humid.

Condensation On Crawl Space Pipes and ducts: When you notice condensation “sweats” along the pipes and ducts inside the crawl space, then that is a result of high humidity levels.

Allergic reactions: If you feel irritated anytime you are around your crawl space, then that could be a result of mold growth in that area. Remember, mold is allergenic, and it can only grow in humid areas.

Soft or saggy floors: Humidity doesn’t only lead to mold growth and musty smells, it also soaks up the materials around it. This includes the floors of the crawl space.

So if you find that it is becoming soft and has a saggy feel, then it is a result of high humidity levels.

If you notice one or more of these signs in your crawl space, then it’s a result of high moisture levels.

A crawl space dehumidifier can come in handy if –

  • Your crawl space is totally encapsulated (regardless of whether there is a drainage system or sump pump)
  • There is no standing water in the crawl space
  • You are afraid that the moisture level is too high

If these are your concerns, then you probably need a crawl space dehumidifier.

Nonetheless, I have to stress the word “encapsulated” which I used above. This is because if there is an encapsulation or vapor barrier system that is incomplete, spent, or poorly installed, then you should address the issue even before you think of buying and installing a dehumidifier.

ESTIMATED: Crawl Space Encapsulation Cost

That being said, a crawl space dehumidifier isn’t the solution if –

  • There is standing water in your crawl space (and your crawl space isn’t totally encapsulated
  • There is ductwork in your crawl space

In this case, you are best advised to contact a qualified contractor to come and assess the situation and develop plans for repairs.

Installing a dehumidifier in a crawl space that hasn’t even been encapsulated is pointless. This is because a dehumidifier is built to remove moisture from indoor air, and not to remove standing water.

The absence of encapsulation and a proper drainage system will mean that the humidity levels in your crawl space will be just too high for a dehumidifier to make a difference.

Advantages Of Using Crawl Space Dehumidifiers

While dehumidifiers aren’t the ultimate solution to crawl space moisture problems, they still have numerous advantages.

Let’s take a look at them one by one.

It helps maintain sound health:

Dehumidifiers improve the quality of the air in a space, and we all know the importance of clean air in an environment.

To add to that, dehumidifiers make your crawl space unconducive to mold growth. Mold is dangerous to health, as it can cause respiratory and allergenic issues.

Without humidity, mold cannot grow.

It helps keep pests away:

There are so many animal and insect pests that are attracted to humid environments. These include rats, roaches, and carpenter ants.

By using a dehumidifier, you won’t just be protecting your health, you will also be protecting the structure of your home.

How do you ask?

Well, pests like carpenter ants and termites are notorious for chewing through wood and other organic materials until they are damaged (sometimes beyond repair).

This means the woodwork under the crawl spaces won’t be safe if such pests invade.

Pests can also migrate from your crawl space to the other areas of the house in search of food. These areas include your kitchen, bedroom, and living room (if you’re fond of eating and dropping crumbs on the furniture).

But once the humidity levels in an area become unfavorable to these pests, they will not be interested in staying.

It helps maintain structural integrity:

In a case where the humidity levels in your crawl space clock are 70% and above, then there is every chance that condensation will be produced.

When condensation levels are high, so is the possibility of wood rot. It is common for wood to experience rot when the air’s moisture content is at least 28% and makes contact with the wood.

Having damaged woodwork under your crawl space is nothing short of a catastrophe, as it will no longer be able to support the weight of your home.

If this happens, then there’s every likelihood that the building will collapse.

We hope that never happens, and that is why a crawl space dehumidifier should be used to keep air moisture under control, which in turn will prevent moisture-induced wood rot.

It boosts the comfort of your living space:

The higher the humidity levels in your home, the less comfortable it will be. Too much humidity can cause your spaces to be hot and sticky.

One would think that turning on the air conditioner would fix this, but you’ll only end up cold and clammy.

This problem can easily be solved by simply installing a dehumidifier in your crawl space. This will help you control humidity levels in your home better, and ensure you and the other occupants are comfy.

Energy efficiency:

Using the AC unit to control excess humidity may not be the best idea. This is because the power the AC will expend in doing this causes your energy bill to go up unnecessarily.

Rather than using an air conditioner, a dehumidifier will be the better option. This will help keep the humidity levels around your crawl space (and your home in general) at or below the 60% mark during any season of the year.


Crawl space dehumidifiers have many advantages. These include keeping your home pest-free, maintaining the woodwork below, and preventing mold growth.

But you have to bear in mind that it isn’t the ultimate solution to indoor moisture. You will still need to install your gutters and waterproof the area for best results.

In fact, a crawl space dehumidifier is not needed if you have an encapsulation and a proper drainage system installed.

You can have a contractor visit you so they can check the status of your crawl space. They’ll be able to give you the best professional advice.

Thanks for reading!

Leave a Reply

Your email address will not be published. Required fields are marked *