A basement properly protected from mold, mildew and other issues caused by too much humidity.

What Is the Ideal Humidity for a Basement?

Updated March 5, 2022 . AmFam Team

Wondering what the normal humidity level in your basement should be? Learn about ideal basement humidity levels and how to reduce humidity in your basement from American Family.

Whether you use your basement as a storage space or comfortable after-work hangout, you know that it tends to hold more humidity than other parts of your home. No matter if your basement is finished or unfinished, those humid conditions can encourage the growth of mold, mildew and other bacteria. To keep everyone in your home healthy, it’s important to check regularly and keep your humidity at an acceptable level.

Need help removing mold from your basement? We’ve got you covered. Plus, check out these tips for keeping your basement humidity at a safe and comfortable level through all of the four seasons.

Normal Basement Humidity Levels

When your basement is too humid, you’ll probably be able to feel it. A comfortable basement should maintain a humidity level of 30 to 50 percent — however, those may differ depending on your climate.

Basement Humidity in the Summer

During summer months, the air outside is hotter and more humid. That air can make its way into your basement, increasing your humidity levels to around 60 percent. Because of this, homeowners must work to adjust those levels back to the ideal humidity level between 30 and 50 percent or risk mold, mildew and bacteria buildup.

Basement Humidity in the Winter

In the winter, cold air from outside can make the humidity levels in your basement drop. And if that cold air is making its way inside, it’s probably having negative impacts on your heating bills, too. During the winter months, you’ll want to keep your in-home humidity levels around 25 – 40 percent when outdoor temps range from 20° F to 0° F, with the lower percentages reserved for the colder temps. Low humidity levels can have adverse effects on your health, causing things like nosebleeds, dry skin and making you more vulnerable to common winter-time sicknesses.

What Causes Humidity in Basements?

Basements are commonly poorly insulated, which allows outside conditions, hot or cold, to have more of an effect on interior temperatures and humidity levels. If a home’s foundation is cracked or its pipes are leaking, the moisture produced can also raise the humidity levels. If you notice that your basement walls are damp or the air seems thicker than usual, check it thoroughly to see if moisture has easy access to your basement.

How to Remove Humidity From Your Basement

If you’ve noticed that your basement is too humid and/or you’ve spotted the culprit, it’s time to act. The earlier you find the issues, and the closer you monitor your basement’s humidity, the more likely your fix will be low-effort and cheap as opposed to an expensive, time-consuming endeavor.

Dehumidifiers Vs. Exhaust Fans

Dehumidifiers come in many shapes and sizes. Refrigerant dehumidifiers work by condensing moisture in the air into water with the help of cold evaporator coils. This type is considered the industry standard for homeowners because it works well at room temperature. Another option is a desiccant dehumidifier, which draws air through a chamber that contains water-absorbing gel packs. These are usually quieter than the other option and draw less power to get the job done. But they’ll also require replacement of the gel-packs after they’re saturated.

Another way to reduce moisture downstairs is to install basement fans to control humidity. Similar in function to a bathroom fan, these high-capacity vents push moist air away from the basement and into the outside air. If used sparingly, you can also run your bathroom fans to reduce humidity in the house.

Buy a Dehumidifier

Putting a dehumidifier in the dampest part of your basement can dramatically reduce its humidity levels. A dehumidifier has a fan that draws in air — that air then runs into cooled coils that remove its moisture and deposit it in an attached tank or down a drain. Make sure to check and empty the reservoir regularly, or talk to a plumber about having your dehumidifier attached to a floor drain.

Repair Pipe Leaks and Foundation Cracks

Patching up a leaky pipe or having a professional plumber do it can solve your humidity problems — and if your foundation has a crack in it, consider sealing them up with caulk and/or having a professional contractor make sure your basement is sealed appropriately.

Plus, when you repair your pipe leaks and seal foundation cracks, you’ll be helping prevent your pipes from freezing when colder weather comes around.

Increase Ventilation in Your Basement

If your basement has windows, consider cracking them open when temperatures are cooler outside than inside to help get rid of some of the humidity. The fresh air can make your basement much more comfortable and reduce the chances of mold and mildew, as long as you don’t leave it open when it rains.

Install Basement Exhaust Fans

Basement bathrooms can produce a lot of humidity, too. If you take a hot shower and the residual steam has nowhere to go, it’ll boost your basement’s levels. That’s why you should consider having exhaust fans installed in your bathrooms and basements — they’ll help get rid of the musty air and extra moisture that put your family’s health and comfortability at risk.

Track Your Basement’s Humidity With a Hygrometer

What better way to monitor your basement’s humidity than with an actual tool that reads its levels? Consider making your house a smart home by installing a smart hygrometer, thermostat and other home appliances that can help you keep your home safe and comfortable with just a couple taps on your phone. One perfect addition is a Smart Security System with flood sensors to help you get news of issues as they’re happening. Plus, you might even qualify for an American Family Insurance smart home discount!

Protect Your Basement from Mold and Water Damage

Staying on top of your home's humidity levels is an important step for protecting your home. Make sure that your home is protected from unnecessary damage with a customizable homeowners insurance policy. Now you can even protect your home from hidden water leaks you can't see in your floors, walls or other unseen areas with Hidden Water Damage coverage.

Looking for a personalized quote from an insurance expert? Reach out to an American Family Insurance agent today to make sure you're getting the peace of mind you deserve.

This article is for informational purposes only and includes information widely available through different sources.

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