Do Crawl Space Ventilation Fans Work? (Which One Should You Get)

If you’ve ever crawled into a dark and dusty crawl space, then you know how important it is to have something to help circulate the air down there. That’s where a crawl space ventilation fans comes in. But do they actually work?

The short answer, is yes, they do. Crawl space ventilation removes excess moisture and all that comes with it (mold and applicable damage). Before jumping on the opportunity to get a crawl space ventilation fan, it’s important to consider the pro’s mentioned above, along with possible cons, like how improper installation can actually increase risk of leaks and mold.

Before making a big decision like hiring a professional to install a piece of machinery into your home (or attempting to do it yourself), it’s important to research possible benefits and drawbacks, as well as which type you should get. 

Rushing into a decision could result in the eventual need for the removal of the fan in order to replace it with something better, which will cost more time and money in the long run.

In this article, we’ll discuss the different types of fans (and if they’re worth installing), what they all do, and how they can improve your home’s indoor air quality.

Let’s dive in!

What is Crawl Space Ventilation?

As the name suggests, crawl space ventilation is the process of removing moisture, humidity and odors from your crawl space. A healthy and well-ventilated crawl space is one that allows for constant air movement throughout your home.

The right type of fan can make a big difference in terms of how much moisture they remove from your basement—and ultimately, their effectiveness as an investment.

Crawl Space Ventilation Diagram

To ensure that you get what you’re paying for when investing in a crawl space ventilation system, follow these tips:

  • Get a quality fan that is designed specifically for use in basements or other areas with limited headroom:
    This is an important point to focus on- in that picking the most efficient, well functioning fan isn’t going to help if it doesn’t simply fit in the space you’re purchasing it for.
  • Invest in multiple fans if necessary:
    In very large spaces, sometimes more than one crawl space ventilation fan can prove to be beneficial for the same reason one is useful in general. When covering a very large square footage, it’s wise to consult a professional regarding how many crawl space ventilation fans would be necessary to garner the desired result.

How Does Crawl Space Ventilation Work?

Crawl space ventilation fans are installed in the floor or walls to pull warm air out of the crawlspace.

They can be installed in a crawl space with an existing forced air system, but they can also be used when there is no forced air system in place. Some people install ventilation fans directly above their crawl space doorways and use them as part of their HVAC systems.

Regardless of where or how you decide to install them, installations of this caliber are usually best done by a professional. Very few things are worse than spending large sums of time and money trying to do something yourself, only to realize you later will have to pay a larger sum of money for someone to undo what you had tried to do, and redo it themselves, but correctly.

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Choosing where to install the the crawl space ventilation fan alone is a task worthy of calling a professional, and the decision shouldn’t be made haphazardly.

Benefits of Crawl Space Fans

The benefits of crawl space ventilation fans are numerous, but we’re going to focus on the main 3 to give you a good idea as to what installing one could do for you and your home. Installing a crawl space ventilation fan can decrease the chance of humidity build up, mold growth, and unstable temperatures within your home.

Read on to learn how each of these benefits can impact you in a positive manner.

Decreased Humidity and Mold/Mildew Growth:

A well-ventilated crawl space will decrease the humidity levels in your home. As a result, mold and mildew won’t have as much opportunity to grow in your damp crawl space. In addition, a well-ventilated crawl space can prevent mold from building up on your walls and floors. A damp environment is the perfect place for mold to grow, and that’s why it’s so important to have a ventilation fan installed if you want to avoid dealing with mold related issues.

Mold is often treated as the substance which shall not be named- a substance causing a creeping fear in homeowners and contractors alike.

If you don’t already know, mold can be harmful to people’s health if it is allowed to grow unchecked in living spaces. In addition to mold just being overall expensive and inconvenient to identify and fix, mold can also cause respiratory issues as well as allergies for some people when inhaled too often. If you’re worried about mold in your home or business, it’s important to have a ventilation fan installed. h

Most people recognize that mold is serious enough to be dealt with ASAP. Reduced humidity levels in a properly vented crawl space will help reduce these issues so that mold doesn’t get out of control inside your home.

This reason alone is one of the main reasons that homeowners opt in to getting the crawl space ventilation fans installed sooner, rather than later. Although this reason might be enough to convince you, let’s continue through the article to learn about one last benefit we have left to explore.

Stabilized Temperatures Inside Your Home:

Another benefit of installing an exhaust fan for ventilation at the top of your crawlspace is that it helps stabilize temperatures inside your home by balancing out how much heat rises up from outside versus how much escapes through vents.

This alone also helps keep homes cooler during hot summer months! If you live in a state with a high range of temperature fluctuation, stability can benefit you not just in terms of comfort, but also in terms of helping to keep your energy bill stable.

This means that less energy is needed to run air conditioners or heaters because they aren’t working against each other anymore either way – especially if you live somewhere where temperatures fluctuate greatly between seasons. The more stable you make your home, the less likely it is that there will be drastic temperature changes between inside and outside. This means that your air conditioner or heater doesn’t have to work as hard, which saves you money on utilities. In addition to this, if your house is more thermally stable, there’s a greater chance of using less energy overall in order to maintain comfort levels.

Downsides of Crawl Space Fans 

While crawl space fans can often be a great way to improve the air quality in your home, there are some considerable downsides to consider. It’s important to consult a professional to make sure that in your individual home’s case, the installation of a crawl space fan would have more benefits than drawbacks and wouldn’t result in additional work or unnecessary costs.

Let’s look at the main to possible downsides of the instillation of crawl space fans:

Improper installation of a fan can lead to leaks and damage from water or mold.

In addition to the possibility of leak damage, ventilation fans can also create an opportunity for pests like mice and rats to enter your home through the hole left by the hole for ventilation. If this would occur, it would result in you having to call not just a ventilation professional, but also your local pest control.

Additionally, if you have an older home with inadequate insulation, installing a crawl space fan could increase energy use as well as potentially cause damage from increased heat flow through your attic area.

Each of these issues can be mitigated by hiring a professional to investigate, begin, carry out, and inspect the project from start to finish.

Should You Install a Crawl Space Fan?

Deciding to install a crawl space fan is a big decision. It’s not as simple as just picking up the phone and ordering one. We’ve already dug into possible benefits and drawbacks, but let’s take a moment to recap what we’ve gone over to help you make the best choice for your specific situation.

You have to consider several factors, including the size of your crawlspace, the type of insulation you have installed in it and whether you want a vented or non vented system (which must be determined by a professional).

Is your home built on concrete or wood? Are there windows nearby? Do you need a vented or non vented system? All these factors can affect how much air circulation you need in order for your space to stay comfortable.

If you’re going to install a crawl space fan yourself, make sure that you have experience with electrical wiring and understand how motors work—and if not, hire someone who does!

If you’re already noticing issues with leakage (or mold), it may be better to call the professional first who could then help you with the evaluation process and possibly move forward with executing the installation sooner rather than later.

Hire A Professional

As mentioned earlier, tackling a project of this potential magnitude could result in excess costs from the labor and billable hours required to undo what you had tried to do. It also could end up eating a large amount of time that you could’ve spent elsewhere.

Hiring a professional, though usually more money upfront and results in less of a headache later on. Hiring a professional also results (usually) in work done correctly and throughly- which results in less follow up required from the homeowner. 


If you have a crawl space, it’s easy to see why there are so many fans on the market.

However, before you run out and buy one of these products, it’s important to remember that they may not be right for your home.

If you have a small crawl space with no ventilation issues and low humidity levels, then a ventilation fan might not be worth the investment. In addition, if your home doesn’t have air conditioning or other cooling systems that bring moisture into your living areas (like bathrooms or kitchens), then there’s a chance that these fans could cause problems for you over time.

For most people, however, the installation of a vented or non vented crawl space fan can be one of the most beneficial things you could do for your home- both to prevent leakage problems and the possibility of mold growth from excess moisture. In order to get this done, you have two options; do it yourself or call a professional. (One is definitely preferred)

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