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Will A Dehumidifier Kill Mold

Will A Dehumidifier Kill Mold? You’ll Be Surprised!

Dehumidifiers have been trendy recently. More and more homeowners are aware of their benefits and have decided to give it a try. Since dehumidifiers can regulate indoor humidity, many users wonder if they can kill mold. 

Unfortunately, a dehumidifier will not kill mold. It can prevent mold growth in the first place or restrain it from spreading, but you should take other measures if the mold has shown up in your house. 

Most people don’t really understand the relationship between mold growth and dehumidifiers. In this post, I will provide all the information you need to know about this subject so that you can better understand controlling mold at home. 

What causes mold to grow?

As a property owner, you must deal with various home creatures, like bugs, molds, mildew, and so on. Sometimes, it could be very frustrating and time-consuming. 

Mold can appear everywhere at home, but the bathroom, kitchen, basement, and crawlspace are the most common locations for them to thrive. This is because these places are the wettest places at home, offering the perfect condition for mold growth. 

Mold spores need water, food, and warm air to thrive. The food source is plenty for mold, including wood, paper, wallpaper, paint, and carpet, which you can find everywhere in the house. As for temperature, the best is between 77° F and 86° F, but they can still survive in colder or hotter places. 

That explains why the areas I mentioned earlier are a breeding ground for mold because they are closer to water sources or more prone to condensation and water leaks than other areas.

Water or moisture plays an important role in the growth of mold at home. Wherever there is excess moisture, there is a higher chance of the presence of mold. 

Will a dehumidifier help with mold?

will a dehumidifier help with mold

Now that you have already understood the importance of water for mold. Since a dehumidifier is responsible for removing the moisture content in the air, it should have some effects on the mold. 

In fact, a dehumidifier can help with mold. When the air is humid, condensation is easier to form since the air can only hold a certain amount of water.

Once the condensation appears on the windows, walls, or other surfaces, the new water source can attract airborne mold spores to stay and thrive. Aside from that, many species of mold can make use of water vapor in the air directly. (It is also the reason why a humidifier can cause mold.)

Usually, to prevent mold growth, it is recommended to control the humidity level between 35% and 55%.

The primary function of a dehumidifier is controlling the humidity level. By maintaining the indoor humidity at a comfortable level, the dehumidifier can prevent condensation and provide less water for mold to draw. 

If you run a dehumidifier before the humid climate arrives, it can prevent the mold from showing up because it stops condensation and excessive moisture in the air. 

When you use it after mold patches appear on the walls, it can help inhibit the situation from getting worse by limiting the water source. 

Can a dehumidifier kill mold?

Even though a dehumidifier can help control mold growth, it can’t kill mold.

The dehumidifier collects water through a condensation process. There are no chemicals used in the process, and no extreme high or low temperatures are produced. As a result, the mold cannot be killed while in operation.

Regarding the molds on the surfaces, the lower humidity level can restrain the proliferation but can’t affect the remaining mold too much. 

When the moisture is removed, the mold can convert from active to inactive (also known as “dormant.”) They are still there and can be activated whenever there is enough water or food. 

Therefore, you can’t expect the mold patches on the wall will disappear after running a dehumidifier for a few days. Besides, the situation can get worse if you stop running your dehumidifier.

Will a dehumidifier remove mold?

An air filter is usually included with a dehumidifier. Unlike an air purifier, however, its purpose is to collect dust and dirt rather than mold spores.

Furthermore, the condensation and reheating processes are unable to kill or settle the mold, and the air expelled contains almost the same number of mold spores as before. As a result, a dehumidifier will not be able to remove mold.

Best ways to kill mold at home

best way to kill mold

Albeit a dehumidifier is not capable of killing and removing mold, there are ways to do it. While professional mold remediation is effective, doing it yourself can save you a lot of money, especially if the condition is not too bad.

Remove mold spores with cleaners 

Many household cleaners can be used to kill molds


Bleach is effective at removing mold spores from tiles, glass, and other non-porous surfaces, leaving a mold-resistant surface. It cannot, however, penetrate porous materials and can emit harmful fumes.


Vinegar is a mild cleanser without releasing any toxic fume and is able to kill 82% of mold spores. You can spray some distilled vinegar on the surface and allow it to sit for an hour before wiping it down. It is not good at removing mold stains. 

Hydrogen peroxide:

Hydrogen peroxide is safer than bleach but is still very effective. You can spray a 3% concentration of hydrogen peroxide on the surface, allow it to sit for 10 minutes, and then wipe down the surface. 

Other effective cleansers include ammonia, borax, baking soda, and tea tree oils. 

Use an air purifier

The air purifier’s HEPA filter can capture airborne mold spores. Even though it is impossible to remove all of the airborne mold spores, an air purifier can significantly reduce the concentration.

In a nutshell, you can use the cleaners to kill and remove the mold on the surface and use an air purifier to remove the mold spores in the air. 

How to prevent the mold from showing up again?

No matter if you use a dehumidifier to regulate the humidity or a cleaner to kill the mold, it can only address the symptoms. 

To prevent the mold completely, you should inspect the root causes and eliminate the source of moisture. For example, you should replace the leaking pipes, fill the cracks, or install insulation. Running the exhaust fan after a hot steam shower is also beneficial. 

Open windows when the indoor air is humid and stagnant but don’t do that when it is raining.


A dehumidifier can help with mold but can’t kill it.

It can prevent and control mold growth by removing excess moisture from the air. However, the mold on the surface will remain and thrive once the device is turned off.

The air drawn into the machine will turn to be drier and warmer, but it wouldn’t be free of mold spores after the process. You should use some cleanser to remove the mold on the surface and use an air purifier to capture the airborne ones. 

What’s important is that you should find the root cause of moisture in the house so as to get rid of mold completely. 

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Liz Yang is the founder of Airsmartly. She has been working at home for a few years and realizes that the performance of the HVAC system plays such an important role in our life. She has tested more than 150 products in person, including humidifiers, air purifiers, dehumidifiers, and ACs, and wants to share tips about using or troubleshooting these products with you. Her uncle is an HVAC expert with over 30 years of experience in the field, and often offers assistance when she is unsure how to handle a situation. He is also in charge of reviewing the articles on this site.

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