What Is a Good Humidity Level for a Basement?

While it’s easy for us to determine a comfortable temperature in our home, it can be a lot more challenging to tell if our house is appropriately humid, especially in the basement. What is a good humidity level for a basement?

A good humidity level for a basement is between 30 and 50%. Humidity levels vary seasonally based on the heat and humidity outside, so your basement will be on the higher end of the spectrum in the summer and the lower end in the winter.

What Is a Good Humidity Level for a Basement?
There are more than spooky things down in that basement.

Let’s take an in-depth look at why we have humidity in our basements and what we can do about it.

Good Humidity Levels for Basements

For many reasons, basements tend to be the area of the house that retains the most moisture.

It’s important to remember to pay attention to the humidity and make sure that your basement stays at a good humidity level.

Related Article: If you feel you have high humidity in your home, testing your humidity levels in your home is recommended. Where To Place a Hygrometer in a House?

The ideal moisture range for your basement is anywhere between 30-50%, although there’s some wiggle room with this average.

You’ll find that your basement has a lower humidity level in the winter when it’s colder outside, and there’s less humidity in the air. If you live in a moderate climate, you’ll notice the moisture levels of your basement drop, but you likely won’t see the humidity level of your basement fall below the 30% mark.

However, if you live somewhere that experiences more extreme winters and has stable temperatures below 20℉ (-6.66℃), don’t be surprised if you see your humidity level fall closer to 25%.

This humidity level isn’t alarming in conditions where the air is so cold and dry, but if it falls below 25%, you should consider taking action. Getting a humidifier can increase your basement’s humidity levels and make your entire home more comfortable.

However, a basement getting too dry in the winter doesn’t happen near as often as basements that get too humid during the hotter summer months. 

Your basement humidity levels will likely be on the upper end of the average range during the summer. Still, if you live somewhere incredibly humid, seeing levels slightly higher than 50% is okay.

Any time your basement humidity rises above 60%, it’s considered outside of the healthy humidity range, and you may want to contact a professional to assess your options. 

Related Article: How Does Humidity Affect the Building Structure of a House?

Or, before doing that, you might get a dehumidifier to help dry it out.

And, if your area is prone to flooding, having a sump pump, or a portable pump, on hand is a good idea. But even if your basement isn’t wet from flooding, a good fan to circulate the air will also decrease the humidity levels.

Typically, when a basement falls outside of the healthy humidity range, it’s easy to tell. If you’re noticing that your basement feels humid, it has probably slipped outside the normal range.

What Causes High Humidity In Basements?

There are several reasons why your basement might have slightly higher than average levels of moisture. While it’s normal for your basement to be the most humid part of your house, you still want to ensure it stays at a good humidity level.

Because basements are often built with inferior insulation compared to the rest of the house, they’re more susceptible to changes in temperature and humidity.

Furthermore, basements tend to hold more humidity than the rest of the house because they’re cooler and underground, which means less ventilation and air exchange.

If you live in a rainy area, it’s common for basements to absorb the water soaked into the ground from rainwater into the basement through the porous concrete.

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Basements also absorb humidity from internal sources of moisture, such as steam from bathrooms and cooking, unvented dryers, or humidifiers. Although these cause basements to be more humid than the rest of the house, this doesn’t necessarily mean they’ll fall outside the healthy range.

However, if your basement is consistently well over the humidity threshold, it could be due to a more severe problem. 

Potential causes of higher moisture levels are:

  • Faulty gutters or downspouts.
  • Possible leaks.
  • Foundational cracks in your house.
  • Condensation settles from the warmer outside air.

What Happens When a Basement Is Too Humid?

If a basement is too humid, it becomes a breeding ground for fungus, mold and mildew, and other bacteria that can be extremely harmful to your health. Additionally, dust mites and other allergens require moisture to stay alive, which makes humid basements the ideal home for them. 

If you feel like your basement is too moist, you’re probably right. 

It would be beneficial to invest in a hygrometer, such as this Govee Wi-Fi Thermo-Hygrometer from Amazon.com. This little device is extremely accurate, can connect to your phone, and can be safely placed anywhere.

Hygrometers are relatively inexpensive and an excellent way of tracking the humidity in your basement. They measure the relative humidity in your space and alert you to unhealthy levels of moisture.

Keeping track of the humidity levels of your basement isn’t only crucial to the overall condition of your home but essential for your health and well-being.

While it may not seem like a big deal to have a humid basement if you never use it, remember that the air in your basement connects to the rest of your house through ducts, so you’re still breathing the basement air even when you’re not in the basement itself.

Related Article: What Causes Mold to Grow in a House? Hidden Mold Happens

Signs That Your Basement Is Too Humid and What To Do About It

If your basement is too humid for too long, it’ll adversely affect your house long-term. Signs that your basement has too much moisture in it can include:

  • Visible mold.
  • Bubbling paint.
  • Window condensation.
  • Water stains on the ceiling, walls, or floor.
  • Feeling a thickness in the air when you enter your basement.

While all of these issues could pose real threats, mold and mildew are primary concerns for your overall health.

Mold poisoning is extremely dangerous, and you often don’t even notice mold growing, as it can grow under carpets, in the walls and subflooring, or in other places.

Conversely, if your basement falls below the healthy humidity range, you could see signs such as peeling paint and experience effects such as dry skin or sinus and respiratory problems when you’re in your basement.

If your basement gets to such a high level of humidity that you’re seeing warning signs, there’s likely a more extensive root problem, such as a leak, that’ll need to be addressed.

It’s essential to deal with these problems as early as possible, as they tend to spread and get worse as they pass to other areas of your house.

If you’re seeing minor oscillations in humidity level that could be considered normal, and are simply looking for ways to reduce humidity healthily, consider a dehumidifier.

Dehumidifiers, such as this Waykar Dehumidifier from Amazon.com, are great for managing basement humidity.

This dehumidifier is large enough to work for your entire home, and it has rotatable wheels that allow you to move it wherever you need it.

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It could also be beneficial to install basement exhaust fans. These fans are designed to push humid basement air directly outside through exhaust vents.

Another helpful way to decrease basement humidity is by increasing ventilation. Moisture in the air is attracted to the cool surfaces of a basement.

By opening the window on days when it’s cooler outside than inside (assuming it isn’t raining), you can reduce the humidity of the inside air.

Frequently, basements are carpeted. Carpeting holds moisture much better than hard floors do, and it often hides mold or mildew that can’t be seen. By removing carpeting in your basement, you provide one less area for moisture retention.

8 Steps to Get Rid of Humidity in the Basement

A good humidity level for your basement is around 30%, and there are things you can do to make that a reality.

8 steps to get rid of the humidity in your basement:

Step 1. Turn on Your Heat

Furnaces make the air in your home drier by bringing in dry air from outside. Keep in mind, however, that it’s not the heat that lowers the humidity, it’s instead the dry air that’s brought in from outside.

Step 2. Good Ventilation

Opening windows to circulate the air will do wonders to lower the humidity in your basement. As the air from outside blows through the home, the fresh air takes over and naturally lowers the humidity to good levels.

Step 3. Look for and Repair Plumbing Leaks

Water leaks follow gravity and gradually make their way down into the basement when left unrepaired. The havoc that a neglected water leak can have on humidity levels is tremendous, not to mention providing an environment for mold and mildew to feast upon.

Step 4. Use Exhaust Fans

If your laundry room happens to be in the basement, make sure the dryer is properly vented to the outside. Exhaust fans should also always be used in bathrooms and kitchens to keep humidity at bay.

Step 5. Keep a Clutter-Free Basement

Although clutter itself is not the cause of rising humidity levels in a basement, the moisture that humidity produces will collect on boxes and other nooks and crannies that mold and mildew love the nestle into.

High humidity and mold go hand-in-hand, so keep a clean basement.

Step 6. Use a Dehumidifier

A dehumidifier will help dry the air in naturally wet areas like crawl spaces and basements, preventing mold development and decreasing musty odors.

Step 7. Seal Your Ductwork

If there are cracks that enable moist air to escape, the ducts that circulate warm and cold air throughout your home may also contribute to humidity in the basement.

Step 8. Test Basement Humidity Levels with a Hygrometer

Purchasing a hygrometer is a small yet worthwhile investment that helps you be more in control of the humidity levels in your basement. This little gadget measures the humidity in the air, so you’ll always know where you’re at.

A good humidity level is considered between 30 to 50%.

Final Thoughts

While humidity is essential to prevent adverse effects from overly dry conditions, it can become too much, as it can negatively affect your health, and monitoring your basement humidity is an integral part of being a homeowner. 

If you’re concerned that your basement is humid, install a hygrometer to monitor it.

An ideal basement falls within a humidity range of 30–50%. If you’re seeing a humidity level outside that range, you might have a problem and need professional help.

A dehumidifier can be an excellent tool for maintaining a healthy humidity level during the winter.


Trina Greenfield, Author
SmackDown Media LLC

About the Author:
Trina Greenfield, the owner of SmackDown Media LLC, is passionate about providing information to those interested in the air quality in and around their homes. Trina writes content about things she’s passionate about, such as safe, in-home air, educational platforms for children and adults, as well as all things family-related.