Can High Humidity in a Home Cause Mold? Protect Yourself

The one place you want to know is safe is your home. You may be wondering about the effects of high in-home humidity levels. Can high humidity in a home cause mold?

In-home humidity levels higher than 55% can cause black mold to grow. The humidity levels can vary greatly within each room, making some rooms more susceptible to the growth of mold. Maintaining a humidity level of between 30 and 50% is recommended to prevent mold and many indoor allergens.

Can High Humidity in a Home Cause Mold? Protect Yourself
This mold is easy to see. Be aware, however, that mold is good at hiding, too.

Many circumstances contribute to the growth of mold in a home.

Where there is moisture there is likely black mold. And keep in mind that just because you cannot see mold, that doesn’t mean you don’t have mold in your home.

One may naturally expect that if they have mold in their home, they would see it growing on their walls and other places.

The hidden mold that we cannot see is also referred to as invisible mold.

Mold spores get into the air and contribute to what many experiences as an allergic reaction. explains some common symptoms of inhaling black mold spores may include but are not limited to:

  • Lung infections
  • Respiratory illness
  • Rashes on the skin
  • Diarrhea, fever, and chills
  • Headache
  • Irritated eyes
  • Sore throat
  • Coughing, wheezing, sneezing
  • Asthma
  • Foggy memory or confusion
  • Fatigue

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

Can High Humidity in a Home Cause Mold?

In-home humidity levels can change dramatically for many reasons. Can high humidity in a home cause mold?

High humidity in a home can cause mold by creating moisture in the air. When this moisture comes into contact with a cooler, hard, porous surface, mold can begin to form. Regulating the humidity levels in each room is key to preventing the growth of black mold in a home.

There are several causes of high humidity in a home. A leaky pipe may go undetected and cause mold.

Other water leaks that eventually collect behind drywall can be easily overlooked.

Floods in a home can create optimal conditions for mold growth before a home has dried out.

Leaky roofs may also trigger the growth of mold.

The most common way to control your home’s humidity level is through your air conditioning system.

Within a home, each room’s humidity level can vary greatly.

For example, a cool basement with little ventilation generally has higher relative humidity. This is an ideal place for black mold to flourish.

Another thing to watch out for is condensation or rust on windows, walls, or pipes. Rust on pipes is a red flag telling you there may be a water leak or a high humidity level problem.

Mold on walls may appear different depending on its stage of growth. Watch out for yellowing on a wall which may turn to a green, black, or brown color.

The condition of the interior paint may also serve as another clue to the possible existence of mold. Is the paint peeling or cracking in places?

Mold may also be seen on bathroom tiles, as bathrooms generally have higher humidity than other rooms in the home.

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

Are there places in your home that smell musty or mildew? This can be a strong indication that there may be black mold flourishing somewhere.

For more information about mold in your home, contact the United States Environmental Protection Agency.

In situations where water has accumulated in inappropriate places, such as a water spill or an overflown toilet, be sure to clean the water up within one to two days to prevent mold from growing.

The sooner repairs can be made to leaking roofs and leaky pipes, for example, the better off your home will be in preventing or stopping the conditions allowing the black mold to thrive.

Mold produces spores that circulate in the air and may cause a variety of relatively mild symptoms such as dehydration, sleep problems, and allergies.

Our bodies have a more difficult time keeping themselves cool when the humidity levels rise.

The humid air does not evaporate the accumulation of sweat on our bodies, therefore we produce even more sweat to compensate.

Along with the dehydration that occurs, our bodies are also depleted of necessary minerals during the sweating cycle. Drinking plenty of water at high humidity levels is extremely important.

Because high humidity levels overheat our bodies, we are more apt to be uncomfortable when we sleep, tossing and turning.

This in turn leads to not getting enough solid sleep that we need to rejuvenate and be ready for the next day.

Perhaps one of the most common symptoms of in-home mold is the allergens that high humidity creates.

Not only does a high humidity welcome mold, but other airborne allergens will likely be sharing the air with the mold spores.

Damp moisture leads to bacteria growth that eventually becomes inhaled into the lungs. Further, one of the most common in-home allergens is dust mites.

Most homes have some level of dust mites. Yes, in higher humidity dust mites thrive. These microscopic organisms absorb the moisture in the air, which is needed for their survival.

Dust mites create airborne allergens that can trigger serious asthma attacks as well as more mild yet annoying symptoms.

Aside from all of the ways that higher humidity can affect us, let’s not overlook the importance of the physical structure of our home.

An overly humid home can cause the wood to swell, as well as dry rot and eventual deterioration. Not to mention rust and oxidation.

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

What Should the Humidity Level in My House Be?

To address a mold issue in your home or to simply prevent in-home mold growth in the first place, we need to address the ideal humidity levels for a home. What should the humidity levels in a house be?

Humidity levels in a house should be between 30 to 50% to eliminate mold growth. Mold flourishes in higher humidity levels and therefore should be avoided. Some measures can be taken to control the humidity levels in a house, eliminating the chances of mold growth.

As temperatures go up and down, the capacity of air to hold water changes. Air can hold more water as temperatures increase.

When humidity is routinely higher than recommended, the accumulated moisture causes mold growth leading to problems with one’s health as well as damage to the home.

Structural damage to a home due to mold is of great concern and should be addressed if suspected. Mold flourishing on floors, foundations, and walls can cause significant structural damage.

Mold damage to a home should be immediately attended to and corrected to prevent further weakening of the home’s integrity.

Unattended mold will eventually rot the structure leading to costly damage control.

On the other end of the spectrum, humidity levels in a home that are extremely low can cause dry, itchy skin making you and your pets very uncomfortable.

According to The Mayo Clinic, the ideal humidity in a home is between 30 to 50%.

Some measures can be taken to balance your in-home humidity to levels beneficial to both your health and your home.

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?

How Can You Measure Humidity in a Home?

To stay on top of the humidity in your home, you are going to need a way to measure the humidity. How can you measure humidity in a home?

There are several ways to measure the humidity in a home, such as the use of a hygrometer which measures the amount of water in the atmosphere. Ice in a glass to test for condensation on the outside of the glass is another way to measure humidity, as well as the wet and dry bulb method.

4 Ways to Measure the Humidity in Your Home:

1. Ice cube method.

2. Use a hygrometer.

3. Wet and dry bulb test.

4. Use a homemade hair hygrometer.

The Ice Cube Method

A common way to test the humidity is to place two or three ice cubes into a glass. Add water and stir. After about three minutes, check to see if moisture has formed outside of the glass.

If there is no moisture on the outside of the glass, the air is considered too dry and you may want to use a humidifier.

If there is condensation on the outside of the glass, this indicates that the humidity level is too high.

Which begs the question, how then do you know when you have a good humidity level that is just right?

The Hygrometer

The most efficient way to measure the humidity in a home is by using a hygrometer.

A hygrometer is a device that operates as an indoor thermometer as well as monitors the humidity levels in your home.

There are several varieties of hygrometers, and they work a bit differently. They all, however, measure the moisture in the air to give you an idea of the humidity levels.

The Wet and Dry Bulb Method

The wet and dry bulb method is one of the simplest ways to measure in-home humidity and involves the use of two mercury thermometers.

To try this method of testing your in-home humidity, place a fan in the room you will be testing and aim the fan directly toward where you will place the thermometers.

Shake your two mercury thermometers until the mercury has relocated into the bulb ends of each thermometer.

Using a piece of cloth or something else that absorbs moisture. A cotton ball is ideal, or simply use a small piece of cloth.

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

Dampen the cotton ball, yet not to the point of dripping, and tape it to a bulb at the end of one of the thermometers.

Room temperature water is best so as not to influence the reading on the thermometer.

Place your two thermometers in the room you wish to test, making sure to put them directly in the line of the fan air. So to recap, one thermometer’s bulb will be covered in a wet cotton ball, while the other thermometer is not.

Check the temperature difference between the two thermometers after about five minutes has passed.

Make note of each temperature reading. Subtract the wet-bulb reading from the dry-bulb reading to find the depression value.

Our demonstration covers only a rough overview of how the wet and dry bulb method is used.

There are charts online that can be used to gauge your results to see where your in-home humidity is at.

Using a Homemade Hair Hygrometer

Some interesting videos on YouTube show how you may also test the humidity in your room using strands of hair.

This method is effective, and chances are you have what you need in your home to test the humidity with your hair.

9 Ways to Reduce Humidity in a Home?

There are several ways you can reduce the humidity in your home. With a little creativity, you will be able to find some relief.

9 Ways to Reduce the Humidity in a Home:

1. Airdry Laundry Outside

There are times when we cannot put our washed clothing into the dryer. The dryer can be very harsh on our clothing.

Each time you clean out that dryer vent, you are removing material particles that came off of your clothing during the drying cycle.

Air drying can be much kinder to your clothes, which in turn helps them to last longer.

Most of us either use racks made to airdry clothing, or we simply hang our clothes over a chair or in the closet to dry.

However, airdrying your clothing indoors creates a good deal of humidity.

When possible, it is recommended to air dry your clothing on drying racks outside or use a good, old-fashioned clothesline.

Understandably, this may be unsightly to neighbors, so try to do this in a way that doesn’t flaunt your clothing and forces others to have to look at it.

2. Use an Air Conditioner

By using an air conditioner, you lower the humidity by adding cooler air into your home.

It’s important to make sure you are changing your HVAC filter on a routine basis to ensure your AC is working effectively.

3. Consider Using a Dehumidifier

The use of a dehumidifier is the way to go if you can swing it. You do not have to spend a lot of money to be comfortable in your home.

Some dehumidifiers fit inside your furnace, or there are stand-alone dehumidifiers that you can put in each room to lower the humidity.

The added benefit of using a dehumidifier is that you can use your air conditioner less, in turn spending less on your electric bills.

Related Article: Why Is the Paint Bubbling on My Wall?

4. Relocate Plants

We all love plants, and they add a special touch to the environment and feel of our home. Too many plants, however, can contribute to higher humidity levels in your home.

Plants give off a decent amount of moisture which is great for the skin, yet when the humidity is higher, it creates more problems than it’s worth.

Especially if you are dealing with a possible mold problem that needs to be addressed.

Try moving your plants out of a room where humidity is a concern.

And if you are like me and you love your plants, using other suggested methods to address the humidity in your home may be the preferred way to go.

Then your plants can remain as-is and you can continue to enjoy them.

5. Charcoal Briquettes

Who doesn’t love a good barbecue? Whether it be on a gas or charcoal barbecue, the experience is always enjoyable.

Were you aware that charcoal briquettes are good for more than just barbecues? Believe it or not, these little gems absorb moisture.

By using a decorative basket or another small container to put a few of these briquettes into, they will slowly absorb some of the moisture in the air of your home.

Simply replace the briquettes every couple of months.

6. Utilize Your Ventilation and Exhaust Fans

It’s important to always use your ventilation fans when cooking. It’s common to turn the vents off when you are done cooking.

Oftentimes, this does not allow enough time to absorb the moisture in the air.

Running your vents a bit longer can help reduce the built-up humidity in your home from cooking.

7. Attend to Your Gutters

Cleaning out your gutters and making sure they are draining properly does wonders in making sure that water from outside is not coming into your home through hidden leaks you may not be aware of.

Unmaintained gutters are often the cause of water getting into your home, which increases your in-home humidity.

Water damage to a home can be very costly. Dry rot alone can get right down into your foundation and create very serious problems.

Clean out your gutters routinely, and ensure that your downspouts are working properly.

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

8. Check for Leaking Pipes

There are times when pipes are leaking that we do not see. There are, however, signs you can watch for that are warning signs you may have a pipe leak.

Any discoloring on drywall is a good indicator you may have a water leak, as well as paint on a wall that is bubbling up.

Is your utility bill suddenly a bit higher than normal? You may want to do some in-home investigating.

Fix all the leaks and wrap your pipes with insulators to prevent condensation.

9. Avoid Super Hot Water in the Shower

Most of us love taking hot showers. Yet did you know that the moisture in the air created by a hot shower is a huge contributor to the humidity levels in your home?

Keep your ventilation fan running while you enjoy your shower, and leave it on for some time after your shower so it can continue to absorb the moisture in the air.

And if you can manage, reduce your water temperature even just a tad so as not to create as much steam.

This can be done more easily by lowering the temperature on your water heater to prevent the temptation of turning up the hot water just a bit more.

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.