How Can I Increase the Airflow In My Basement?


Most people don’t spend much room in their basements, so it isn’t unusual to forget to open the windows or fail to see just how stuffy the air has gotten.

In case you’ve noticed that it’s time to do something about your basement’s air, maybe you’re wondering, how can I increase the airflow in my basement? The easiest method is by natural ventilation, like opening windows on a dry day and creating a draft. But there are also mechanical and portable ventilation methods as well that you can use to get some airflow going in your basement, like installing exhaust fans or buying a portable dehumidifier.

Let’s explore all those options.


Importance of Basement Ventilation

It’s important to be vigilant about checking the air quality of your basement on a regular basis to prevent costly structural damage that may occur years later. Being early in recognizing problems in basement air quality can save you thousands of dollars.

Because of moisture, there will be a possibility of growing mildew and mold that will cause serious health issues for your family members, not to mention structural damage in the home over time. Research by Green Building Advisor has found that a basement’s foundation walls take up 10 to 15 gallons of water per day, so getting your basement ventilated on a regular basis is very important to get as much moisture out as possible.

How can you understand that your basement is having an issue with moisture? It is very easy. If you find any staining on the floor or walls, you can be sure about it. Moist-to-the-touch foundation walls are a clear giveaway that something’s wrong, especially if this persists even during the summer.

It’s important to get some airflow through the basement and find methods to draw out the humidity so that this kind of damage doesn’t happen.

Another reason why it’s important to have constant airflow in your basement is radon gas, which commonly seeps through the floor and wall cracks from the soil into the home.

Radon gas can cause lung cancer, so it’s very important to be aware of this, too.

Now, let’s take a look at some steps you can take to create airflow and clean the air in your basement.


Test the Indoor Air Quality (IAQ)

Before taking effective measures to increase the airflow in your basement, you must test the quality of the air.

This can range from inexpensive methods like having a hygrometer installed on a wall (if you only care about humidity levels) to expensive methods like having an air quality monitor that connects to your smart phone and alerts you of issues.

You have to have some sort of metric so you know where you need to start.

Everyone can go upgrade their HVAC system, buy fans with larger blades or a large dehumidifier. But if you don’t know first just how polluted your basement’s air is and what its relative humidity (RH) is, you’ll inevitably pay for the wrong thing.


Ways You Can Increase Airflow In Your Basement

Now that you’ve hopefully figured out what kind of IAQ your basement has, you should know what areas you need to improve on to increase airflow.

We’ve categorized the methods you could use as natural ventilation, mechanical ventilation, or portable ventilation.


Natural Ventilation

Natural ventilation is about allowing the natural air to flow to your basement. You know, opening windows and creating a draft.

It sounds simple, except that it isn’t.

There’s a reason why today’s new construction homes are built to be as airtight as possible.

If you aren’t careful, you could introduce humidity and pollution into your home that can cause mold and pollutants that can linger for years.

But you can naturally ventilate your basement, you just have to know exactly when to do it.


When to Open Windows to Reduce Humidity

First, you’ll need a hygrometer and thermometer, which luckily, are relatively inexpensive. Sure, you can check your local weather app on your phone, but it’s always better to know the numbers immediately around your home.

It’s also a good idea to know the dew point, which is the temperature at which humidity is at its peak. Meaning, this is the temperature at which you run the highest risk of introducing humidity in your home if you open the windows.

Follow these steps to find the right time to open the windows.

First, always check the hygrometer for the relative humidity (RH) inside the home. If you can maintain it between 35% to 50%, you shouldn’t worry about opening a window here and there since your humidity is at a healthy level. But once you get above 60% RH, and especially 70% RH, you’ll have to be careful as opening the windows on the wrong day can easily introduce a mold problem.

Next, you’ll need to determine how the inside of your home relates to outside weather.

Say you’re heating your basement at 72 °F, but the air temperature outside is 60 °F and the dew point is 50 °F. This means that the inside of your home would need to get down to 50 °F or lower in order for condensation to occur and introduce humidity into your home. But since you’re heating your home to 74 °F, a temperature far greater than the outside, it means that it’s a good day to open the windows.

Example #2 – you’re heating your basement at 72 °F, but the air temperature outside is 70 °F and the dew point is 68 °F. Notice how close the temperatures are here. Your home’s interior is very close to the dew point and you’ll likely experience a high RH reading on your hygrometer when outside air temperature and dew point temperature are this close. This wouldn’t be an ideal day to open the windows.

Example #3 – your basement is at 60 °F, while the outside air is at 82 °F and the dew point is 75 °F. Since your basement temperature is already below the dew point, it’s not a good idea to open any windows.


Choosing the Right Basement Windows

Now, you may be thinking, this is all great, but what if I don’t have any basement windows to open? If you’re in the fortunate position to tackle on a renovation to add some basement windows, here are few options to consider.


Custom glass block windows

This type of glass is fantastic in terms of generating airflow to the basement.

Plus, did we mention how safe glass block windows are because of their extra thickness? And they’re great for privacy, so glass block windows are often used for bathrooms and homes that are built closely together.

This type of window is energy efficient and does not need any kind of maintenance because its typically sealed with mortar. They are only slightly more expensive than regular windows, but can enhance your home’s curb appeal and appraisal value.


An awning or hopper-style vinyl windows

The difference between awning or hopper-style windows is pretty much how you open them.

With awning windows, you can open the window outwards to get fresh air for your basement. On the other hand, hopper-style windows can be opened inwards.

Unlike a double hung window that typically can only be opened by its lower sash, one of the most important features of the awning and hopper-style windows is the ability to open the entire window. So, you can generate a large amount of airflow in your basement. But as the window can be opened entirely, there is a slight risk in terms of security while using these windows.


Egress windows

Egress windows are simply full-size windows that can be used to escape from a basement. They can help with airflow simply by virtue of their large size.

Obviously, it will be more difficult to add an egress window to an existing home, but if you’re still in the building stages or are getting ready for a basement remodel, they’re worth considering.


Mechanical Ventilation

Mechanical ventilation includes anything in your home that uses ducts or fans and is a permanent structure of your home.

This primarily deals with things like you HVAC system, exhaust fans, and ceiling fans.

Mechanical ventilation is a bit costly as it needs electricity. You’ll need to understand how much electricity your HVAC system will use and probably will need to pair it with an air purifier or dehumidifier to achieve optimal results.

Mechanical ventilation can be done using different ways.

You can use a fan in front of the window to push air out of the basement. Even better, try pairing fans on opposite sides of the basement to get even more airflow.

Another option is to install exhaust fans throughout the basement, each with a humidity sensor that allows it to automatically turn on and off.

There are also more potent (and more expensive) ventilation systems that can be introduced, like upgrading your HVAC or installing the EZ Breathe system.


Portable Ventilation

Portable ventilation is a good idea when you need a quick solution, but it isn’t exactly as long-lasting or as cheap to run on a monthly basis over the long term. If you have money to spare and plan on staying in your home for at least the next 5 years, a more permanent solution (like an upgraded HVAC, whole house dehumidifier or whole house air purifier) may be a better idea.

Having said that, here’s what you can expect from some portable ventilation options.


Portable Dehumidifiers

Portable dehumidifiers have powerful fans inside that help with airflow, plus they tackle the #1 problem that basements have – humidity.

But before you go out and buy the first dehumidifier you see, understand that you’ll need to look for the following things:


  • It’s impossible to expect someone to constantly go down to a basement to empty out a tray full of collected water. For that reason, you’ll need a dehumidifier with a drain hose and know exactly how that hose will connect to the outside (will you crack a window open or drill a hold in the basement wall?).


  • Manufacturers often market dehumidifiers as having the capacity to dehumidify areas with a large square footage. It sounds great because that’s exactly what your basement is. But when you look closer, their math is based on spaces with high temperatures, and basements are notoriously cold. Long story short, always do your research and if in doubt, upgrade to the dehumidifier that has the capacity to cover much more than your basement’s size. And check for AHAM Verifide ratings whenever possible.


  • Be aware of operating costs so you aren’t surprised on your electricity bill.


  • Have a plan on what to do with your dehumidifier over the winter season. Some dehumidifiers need to be cleaned and stashed away during the winter as their coils freeze over and render them inoperable below certain temperatures.


Air Purifiers

Air purifiers are another great way to introduce airflow into a basement and clean pollutants along the way.

While they don’t directly help with humidity, they help with pollutants that can linger for years and severely impact your health.

Look for air purifiers for high CFM (cubic feet per minute) ratings and those that can cycle the air in the room at least 3 times per hour. To make sure yours is filtering the most amount of pollutants in the safest way, look for air purifiers that have a HEPA and activated filter combo and stay away from ozone generators if air purifiers.

More about air purifiers in this post.