What Happens if Indoor Humidity Is Too High?

Experiencing humid conditions when we’re outside can be extremely uncomfortable. But experiencing high levels of humidity in our own homes can be damaging and unhealthy. What happens if indoor humidity is too high?

If indoor humidity is too high, it can have adverse effects on our house and our health. Humidity encourages the growth of harmful mold and allergens, damaging both our property and our respiratory system.

What Happens if Indoor Humidity Is Too High?
Is the humidity in your home too high?

In this article, I’ll discuss the potential issues that arise when indoor humidity is too high, how to determine the humidity levels in your home, and what actionable steps you can take if your indoor humidity is too high.

Effects of High Levels of Indoor Humidity

While humidity levels vary widely outdoors, the ideal humidity range inside falls between 30-50%. This range prevents our house from suffering adverse effects caused by the air being either too dry or too humid.

While it may be expected for your indoor humidity levels to rise to 60% in the summertime if you live somewhere particularly humid, anything beyond that is problematic.

Related Article: Humidity causes mold and health problems. An ERV system can reduce the humidity in your home significantly. What is an Energy Recovery Ventilator (ERV)? Ultimate Resource

Effects of High Levels of Indoor Humidity on Your House

The biggest issue homeowners face if the indoor humidity levels get too high is mold and mildew growth.

Mold and mildew require humid conditions to survive, which is why you often see mold growth in bathrooms and laundry rooms, as well as around unsealed windows.

Not only is mold unsightly and bad for your health, but it can seriously compromise the structural integrity of your home.

Often, if left untreated, the mold you’re seeing is only a fraction of the mold growing inside your walls, floorboards, etc., which can weaken and rot your home.

Furthermore, most fungi species need humidity levels greater than 60% to grow, so you run the risk of fungal infestations in addition to mold and mildew.

Humidity can damage your home in less impactful ways as well, such as causing wall paint to bubble up and peel if exposed to too much moisture or wall stains. 

Related Article: Can High Humidity in a Home Cause Mold? Protect Yourself

Effects of High Levels of Indoor Humidity on Your Health

High levels of humidity are potentially problematic for your home and pose a real threat to your health. 

There’s evidence that viruses have an easier time spreading in homes with high humidity levels, especially for immunocompromised people.

High humidity levels provide ideal breeding grounds for species such as dust mites, indicating a direct correlation between high indoor humidity and allergens.

Aside from health issues that arise because of potentially harmful substances growing in your house, humidity can also impact your ability to stay calm when combined with extreme heat, putting you at higher risk for heat exhaustion and stroke.

However, the most significant threat to your health from high levels of indoor humidity is mold. 

Mold requires moisture to grow and often becomes a pervasive problem before you’re even aware of it.

Mold can not only replicate asthma-like symptoms, but exposure to it can give you asthma.

It can have severe effects on your health in general, including making you more susceptible to other types of respiratory infections.

If left untreated, constant exposure to mold can extend beyond your respiratory system, and mold poisoning can even go so far as to cause neurological damage. 

Related Article: What Causes High Humidity in a House? Your Questions Answered

How To Tell if the Indoor Humidity Is Too High in Your House

Even if you’re aware of the adverse effects of having high indoor humidity, it’s not always easy to tell if the moisture has gotten too high.

Luckily, determining the humidity levels in your house is quite simple. First, if you feel like the air is too humid, it almost definitely is.

If you’re noticing a wet, heavy feeling in your house at times beyond when you take a shower or run a load of wash, this is an indicator that your humidity levels are too high.

Another sign of moisture is foggy windows or windows with visible condensation on them.

Furthermore, if you notice a musty or mildewy smell in your house, this is an indicator that you likely have mold growing somewhere, meaning your home is too humid.

If you want to keep track of the humidity levels in your house, consider buying a hygrometer.

Related Article: Does Humidity Affect Hardwood Floors? Protect Your Investment

Hygrometers measure the moisture level in your home and report the relative humidity level, just like a thermometer reports temperature. 

While some hygrometers offer more features, such as Bluetooth connection to your phone, there are plenty of basic models that are inexpensive and still provide accurate information.

Hygrometers are a helpful way of tracking the humidity in your house, and you can install them in multiple rooms or areas if you want more accurate readings.

What To Do if the Indoor Humidity Is Too High in Your House

While high humidity levels are problematic, there are a lot of options to correct the situation. 

The key to knowing how best to correct your humidity problem is identifying the source of the moisture.

If your indoor humidity is getting high because of steam from cooking, showering, or running the washing machine, then you may have a ventilation problem.

If you’re confident that the humidity is coming from the house itself rather than environmental moisture, then you may have a leak in your home or a crack in your foundation that you’ll need to get fixed.

If you notice indoor humidity levels getting high, make sure to address the issue as soon as possible before secondary issues like mold growth become a problem.

Run Your Air Conditioner To Lower Indoor Humidity Levels

Air conditioners function to cool the house down and remove hot air from the inside and blow it outside.

Hot air can hold more moisture, meaning that the cooler your environment, the less humid it’ll be.

By running your air conditioner, you’ll be able to lower your indoor humidity level by reducing the temperature and sending hotter, more humid air outside.

Related Article: Why Is There Mold in My Bathroom? We Find Out

The same effect can be reached by opening your windows if it’s cooler outside than inside, and it’s not raining or humid. 

The warmer, humid air will be drawn out while the cooler, dry air will be brought inside.

Install a Whole-House Dehumidifier

If you’re experiencing humidity in one particular area of your house, then a mobile dehumidifier might be a better option for you.

Dehumidifiers work by collecting the moisture in the air and collecting the water in a receptacle that you can empty.

However, if you’re experiencing a more significant humidity problem, a whole-house dehumidifier would be more practical.

These dehumidifiers connect to your HVAC system, effectively removing the moisture inside the house and draining the water outside.

However, before installing a whole-house dehumidifier, you’ll want to address any more significant issues, such as leaks. Without addressing the root problem, the dehumidifier will simply mask the real issue.

Increase Ventilation and Circulation Throughout the House

One of the most straightforward and essential fixes, increasing ventilation and circulation in your house, could solve your humidity woes.

Areas such as bathrooms, laundry rooms, and kitchens should have exhaust fans designed to remove hot and humid air inside and push it outside.

Always run exhaust fans when showering, doing a load of laundry, or cooking. If your humidity issues are more extensive, consider leaving the fan on for several minutes after you’re done with your activity to remove any remaining moisture.

Related Article: How Does Humidity Affect Food Storage? Storage Tips

Ventilation fans are also critical, as they can circulate fresh air into your home. Meaning running a fan when it’s colder out can help disperse some of the stagnant, humid air inside.

Getting humid air out and fresh air in is the primary purpose of fans, and air circulation is crucial for removing humidity. 


If indoor humidity is too high, it can have detrimental effects on your house and your health.

Mold, mildew, and fungal growth, as well as increased allergens and rot, are all possible outcomes if your house is too humid.

It’s essential to keep your home at a relative humidity level of 30-50%. If the humidity level falls above that range in your home, you’ll need to take steps to lower it.

Ways of lowering your indoor humidity could include increasing ventilation and air circulation by venting and exhausting fans, running your air conditioner, or installing a whole-house dehumidifier. 


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.