is 60 humidity too high for a basement

Is 60 humidity too high for a basement?  It is a common yet important question to ask.

Maintaining the right humidity in the basement is essential, or you will never realize how fast the mold takes hold of your space.

Using a humidifier is the way to go here, but ultimately, you must know about the acceptable humidity level in basement.

Ideally, basements should not have humidity over 60%, and levels between 30 to 50% are considered safe, though it also depends on the climate and other factors. 

The Issue of Maintaining the Right Humidity Levels

maintaining the right humidity levels

A high indoor relative humidity causes furnishings and building materials to become saturated with water.

Mold can flourish in the wet conditions created by those materials.

Keep in mind there will be insufficient moisture in the air for mold to grow if the humidity levels are below 60% with no cold-condensing surfaces.

Yet mold will almost surely grow if the relative humidity (RH) hovers above 70% inside for extended periods of time. 

Understanding the Issue of Water Vapors and Humidity

When it comes to dealing with mold growth, relative humidity is important along with condensation of water vapor.

The presence of potentially harmful water vapor should always be avoided.

humidity and water vapors

In the winter, moisture and mold growth can be hampered by properly insulating exterior walls.

Similarly, you should never rely on an unvented gas heater as your primary heat source because it produces excessive water vapor (and other air pollutants).

When taking a shower or bath, the exhaust fan should be on and vented outside constantly.  

Fact: It is possible to reduce humidity inside with air conditioning throughout the summer. 

Importance of Maintaining a Balance in Humidity in Basements

You may have heard people say that it is essential to keep humidity levels in your basement within a set range. But, why is that?

The truth is that you will experience problems if the humidity is a bit too low or a bit too high.

measurement of a balance humidity

For instance: 

When Humidity is Too High

Excessive humidity can promote the formation of mold, which can aggravate existing conditions like asthma and allergies if left unchecked.

If the humidity level is too high, you may notice:

  • Wood flooring to buckle and warp
  • Support beams decay quickly
  • Paint bubbling and peeling 

When Humidity is Too Low

Keeping humidity too low in your basement is not desirable either. Dryness and cracking of wood flooring, furniture, and other items might occur in the presence of a low humidity level.

Similarly, static electricity is another problem that can arise from dry air and is especially dangerous to electronic devices.

Keeping these issues in mind, it is important to check the humidity levels frequently.

It becomes more important after rainy days or other events that might have let moisture seep into your basement. 

An Important Consideration

Using a dehumidifier, ensuring adequate ventilation, and swiftly addressing any moisture problems, especially water leaks are all ways to keep the humidity level within acceptable ranges.

Fact: Air conditioning might sometimes contribute to excessive humidity levels by merely reducing temperature without removing any water vapor from the air. 

Is 60 Humidity Too High for a Basement?

basement with high humidity

The maximum allowed percentage is 60%. Infestation by mold becomes an issue at that level and above. Air leakage is likely to blame for most of the issues.

It means that most people would be willing to wager that if you air-seal the sill plate and rim joist, you will notice a significant decrease in the issue.  

Whatever the case, you should not ignore the problem and take steps to lower humidity in the basement and never let it cross the 60% mark

The Acceptable Level of Humidity in Basement

Between 30 and 50 percent humidity is considered good humidity for basement!

Maintaining humidity levels between 30% and 50% helps to minimize issues, such as:

  • Musty odors
  • Mold growth
  • Moisture damage to your belongings

Always keep in mind that this “acceptable” humidity range may change a little depending on your location and climate.    

Understanding the Normal Humidity Level in Basement

normal level of humidity in basement

Whether it is used for storing items or as a relaxing hangout after a long day, your basement has a higher RH than the rest of the house.

Mold, mildew, and other forms of bacteria can flourish in the damp conditions that exist in any basement, unfinished or finished.

Therefore, humidity levels in the home should be monitored routinely and maintained at a comfortable level to ensure the health of all residents.

So, what is considered normal when you talk about humidity levels in the basement? 

Typical Relative Humidity in a Basement

summertime dampness in the basement

You might be able to feel the dampness in your basement if the humidity level is too high.

Depending on where you live, the ideal humidity for a basement is anything from 30 to 50 percent.

But, be prepared to see it change a little in summers and winters. 

Summertime Dampness in the Basement

The issue of higher humidity in summer can become quite pressing. It is mainly because the outside air is humid and hotter throughout the summer.

It is possible for that air to seep down into your basement, raising the relative humidity there to somewhere near 60%.

Let us assume the external humidity is at 65% on a comfortable summer day of 80 degrees.

This air is conditioned to a temperature of 65 degrees and a relative humidity of 98% after it enters your basement.

If the relative humidity is 70 percent or greater, mold can thrive.

If you ignore mold growth in your basement, it might spread throughout your home and make everyone sick.  

Fact: You notice dew when the relative humidity in the air reaches 100%. 

Winter Moisture and Humidity in the Basement

Humidity levels in a basement may decline in the winter as cold air from outside enters the space. 

Not to mention, if that chilly air is getting inside, it is likely wreaking havoc on your heating costs as well.

winter moisture and humidity

When the external temperature drops below 20F or lower, you should maintain a humidity level of between 25 and 40 percent inside your home.

Keep in mind that reduced humidity can also be harmful to your health, increasing your susceptibility to colds and flu during the dry winter months. 

High Basement Humidity Signs to Check

signs of high humidity in basement

At least 60% of American homeowners have experienced problems with a damp or wet basement.

This shocking number occurs when the three main sources of damp basement issues are overlooked:

  • Subsurface seepage
  • Excess humidity
  • Water intrusion due to rain

Having any of these signs in your basement may indicate that high humidity levels are already causing problems.

For instance:

  • Condensation on appliances or windows
  • Possible signs of mold
  • Weird odors
  • Water damage
  • Rotting wood

What Causes Basements to Have High Humidity?

causes of high humidity in basement

Excess moisture is the ultimate cause of high humidity in your basement, and it could be due to the following major issues. 

Drainage Problems

Waterproofing your basement completely necessitates the installation of proper drainage systems. Humidity can go up with insufficient drainage.

Similarly, another common problem is that yards have a gradual incline that leads water toward houses rather than down and away.

This is a major problem if your downspouts and gutters are also clogged.

Humidity is the obvious result because water is getting into your basement. 

Inadequate Airflow

Not having adequate ventilation in the basement can also increase humidity.

Basements typically have poor ventilation, leaving the moisture trapped there. So, you have to dry out your home with the help of ventilation.   

Domestic Home Equipment
domestic home equipment

Humidity issues can be exacerbated by common household appliances like dryers and washing machines as well as by moist indoor environments.

If any of these machines are in use anywhere near your basement, they may be the cause of the problems you are experiencing.

Fact: Singers will tell you that it is more challenging to maintain a consistent tune when the air is dry and has low humidity since this reduces the suppleness of the vocal cords.


Is 60 humidity too high for a basement? Many experts would confirm that you need to keep the humidity levels below 60% in the basement to avoid mold growth.

Sometimes, you can get away with humidity this high, but you should take it as a cut-off point, and never let it go beyond that.

Try various ways and improve ventilation in your basement to bring those levels down a bit.