Ideal Humidity Level for Basement

Ideal Humidity Level for Basement featured photo

I live with three other people, along with both cats and dogs so I appreciate any extra living space I can get my hands on. Basements are a great extra space in any home but they’re not very ideal when it’s too humid down there.

The ideal humidity level for basements ranges from 30% to 55%. Going lower or above this ideal range could lead to house structural damage and cause various health concerns.

Optimal humidity levels are an every-fluctuating number and can vary depending on where you are, the temperatures inside and outside, and the current season.

Below, I will explain in detail the typical and ideal humidity level for basements and the importance of staying within that optimal range. I will also go over how these levels can change over seasons and what you can do to it in optimal range.

Basements and Humidity: Why Are Basements Humid?

No one likes humidity. Whether it’s too low or too high, it can pose a lot of different problems for many homeowners and the people living in the house.

Basements are a great space in a home for anyone looking for extra living space or looking to build a workstation away from the chaos upstairs.

Basements are positioned closer to the ground and soil. They can be partially or fully parallel to the ground. This is probably the most common reason why basements tend to be more humid than the rest of the house.

Poor ventilation and poor insulation are both causes of high humidity levels. The huge difference between the outdoors and inside the basement can also be a cause for this.

Any leakage in your home’s pipes and water accumulation can both cause high humidity levels down in your basement.

Having and operating home appliances right in the basement can also cause high humidity levels. If you use washers or dryers down in your basement, or hang clothes on a clothesline down in your basement, you might notice excess humidity every time you do your laundry.

Bathrooms and kitchens are common in basements and with their regular use come relatively high humidity levels as well.

Lastly, newly-built homes with new concrete can have a lot of moisture in them. This also causes a spike in humidity in basements.

Which is Better: High or Low Basement Humidity?

Whatever the reason may be behind the fluctuating humidity levels in your basement, you don’t want a basement with humidity levels that are either too high or too low. Both extremes can pose potential problems to homeowners and whoever is living in the house.

Why you don’t want a high humidity basement

High humidity basements pose many health problems for anyone living in the house. Molds, mildews, and other fungal infestations thrive in moist conditions and humid environments. Letting your basement reach dangerously-high humidity levels means you’re essentially welcoming all these into your home.

The air in your basement circulates and travels to the rest of your home. This means your family is potentially breathing in air from a space that has been infested with molds and fungal infections. This leads to many health risks and respiratory problems.

Allergens from such a humid environment can travel up and anyone living upstairs can breathe them in. Allergens are huge contributing factors to asthma and various allergies.

Moisture, humidity, and dampness also attracts termites. Termites, if not controlled and intervened with, can destroy wood and your home’s foundation.

Damp basements with lots of humid air aren’t ideal when you’re planning on converting them to actual living spaces or simply a storage space.

An excessively humid basement can lead to an array of issues in your home and this can further lead to a staggering low in your property’s value.

Why you don’t want a low humidity basement

It’s not only high humidity levels you should be worried about. Basements with very low humidity levels open up a can of issues along the way as well.

Low humidity levels mean excessive dryness and there isn’t enough moisture in the indoor air.

Low humidity levels can cause a variety of respiratory issues. It can lead to cold, dry cough, sinus infections, and even trigger asthma.

Low humidity can also lead to excessively dry skin and scalp, chapped lips, and other skin concerns. Low levels can also have adverse effects on your house’s paint and cause peeling.

Typical Humidity Level for Basement: What is the Ideal Humidity Level for Basement?

Now that we’ve discussed in detail the downsides of having basement humidity levels that are either too high or too low, you might be wondering what the ideal basement humidity level is.

The ideal humidity level for basement is anywhere from 30% to 55%.

Anything below (about 25%) or anything too high (about 55-60%) will cause various health and house problems we’ve discussed right above.

Indoor humidity levels and the ideal range you should aim for would vary, depend on, and fluctuate according to a variety of factors like where you live, the temperature, and the season.

During the summer

Humidity levels are directly related to temperature. When the temperature is high, so is the humidity.

During hot summer months, you should aim for and maintain a 50% humidity level in your basement to prevent issues from arising.

During winter

For cold winter seasons when temperature levels drop, the ideal humidity level is between 25% to 40%.

Why are Ideal Relative Humidity Levels in Basements Important?

Keeping humidity levels at an ideal range is essential if you want to keep your basement free from molds, mildew, fungal infestations, and termites. This is the case whether you have an unfinished or finished basement.

These are very damaging to your home, its foundation, and to those living in it. Excess moisture and a damp environment is welcoming to these infestations and not keeping them under control can lead to damages.

Non-ideal humidity levels don’t only affect the home itself but those living in it. Either too high or too low humidity levels can lead to respiratory issues like cold, cough, asthma, and can trigger allergies.

Both damp or dry basements aren’t ideal living spaces or even storage spaces. If you want to make good use of that part of your house, keeping humidity levels in the ideal range is important to keep it comfortable enough to use and live in.

Does Your Basement Have Low or Excess Humidity?

If you want to keep your basement’s humidity at ideal levels, it’s important to know how you can do it.

Use tools like a hygrometer and a thermometer to keep humidity and temperature levels in check. This lets you know whether you’re in the ideal range and lets you adjust what needs to be adjusted when you’re not.

Installing a humidifier, air conditioner register, or basement dehumidifier is a great way to have control over the room’s temperature and either raise or lower basement humidity level when needed.

Vents and exhaust fans allow for better ventilation to prevent moisture and dampness. Making sure the room is properly insulated by sealing in gaps and cracks prevents any moisture from sneaking into your home. It helps to position your humidity control devices properly, so make sure to check out my separate article on where to place a dehumidifier in a basement.

And lastly, to ensure you are able to keep humidity levels at an ideal range, you should be able to pinpoint what exactly causes the not-so-ideal humidity level in your space. From there, you can start working on solutions to counter it.


Basements provide a great extra space in the house. Whether you want to use it as extra living space, a gym, a workstation, or a laundry room, basements are an excellent choice.

Basements are closer to the ground than the rest of the house. This plus other varying reasons can cause high humidity levels not within the ideal humidity level for basements which is 30% to 55%. Along with other factors like the temperature, season, and where you live, humidity levels can go higher or lower than this range, and the right basement dehumidifier can be a big help with managing this.

And that has been our guide on the ideal humidity level for a basement. For any questions for us, hit us up right below!

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