Does a Dehumidifier Kill Mold?

Mold is a natural part of the environment. Completely eliminating mold and mildew in your home (or anywhere really) is nearly impossible, but give it enough moisture and it can grow rapidly on almost any surface. A dehumidifier does not actually kill mold, but it can prevent mold from multiplying by reducing humidity that mold needs to grow.

You’ll know you have a humidity problem in your home when you notice a moldy smell and feel the muggy and sticky air. In more severe cases, you may find patches of mold growing on walls, wood, and fabric. Don’t wait any longer. Find the source of moisture immediately and stop mold from spreading and prevent its damaging effects.

What Does a Dehumidifier Do?

The main purpose of a dehumidifier is to reduce indoor humidity. It accomplishes this through different methods. Depending on your geographical location and the climate outside, your house may be more vulnerable to excess humidity. In this case, a dehumidifier may be a necessary addition to your HVAC system.

Running a dehumidifier makes the room more comfortable for its occupants and inhospitable for mold, mildew, dust mites, and other airborne allergens. This reduces the risks of health problems in individuals and prevents eventual damage to properties. 

Additionally, dehumidifiers work to eliminate unpleasant odors and improve the air quality. Less humidity in the air also helps dry laundry, preserve stored food, protect electronic equipment, and save important documents. Dehumidifiers are also useful for many commercial applications.

Does a Dehumidifier Kill Mold?

As mentioned above, dehumidifiers do not kill mold. However, they do prevent mold from growing and getting out of control. A dehumidifier helps maintain comfortable humidity within 30% to 50% RH, where mold cannot survive.

Mold is a microscopic organism that belongs in the fungi kingdom. It can grow almost anywhere there’s moisture. Mold needs food and air to survive. Once it spreads, it feeds off of organic materials such as drywall, insulation, wood, carpeting, fabric, and other porous surfaces. Some type of mold multiplies by producing spores that travel through the air. A dehumidifier eliminates mold spores before they find a moist surface to grow and spread in your home. 

Mold problems due to excess humidity may be influenced by many factors. Showers and baths build up moisture in the bathroom. Cooking and doing laundry can also increase humidity. Without proper ventilation or enough airflow, this may lead to mold growth. If the source of moisture is a roof leak, burst pipe, or faulty drainage, it’s important to find restoration experts to tackle these issues before they get out of hand. 

Other Benefits of Using a Dehumidifier

Reduces allergies

Touching mold or inhaling mold spores may cause allergic reactions such as sneezing, runny nose, and itchy eyes. It can also lead to allergy-induced asthma attacks and other respiratory conditions. Likewise, dust mites thrive in humid conditions and trigger allergy symptoms similar to hay fever. They cannot survive when relative humidity drops to 50 percent or below.

Helps your air conditioner

An air conditioner may not be enough to keep you comfortable during hot and humid summer days. It works to lower temperature and reduce humidity to a certain level. However, cooling down heavily moist air makes the job a lot tougher for your air conditioner, which will equate to higher air conditioning bills and less comfort.

Improves indoor air quality

High humidity levels decrease indoor comfort and increase the risk of dehydration. More humid air is more difficult to breathe because the air contains high amounts of water vapor and lower oxygen molecules. Using a dehumidifier keeps out excess moisture and odors, greatly improving indoor air quality for your health and comfort.

Preserves furniture and structures

Dry air preserves the structural integrity of the house as well as the furniture and appliances. Aside from eliminating mold and its damaging effects, maintaining the humidity level within optimal range also helps prevent rapid destruction caused by condensation, rust, corrosion, or pest infestation.

How to Choose a Dehumidifier

Finding the right dehumidifier is no easy task if you don’t know what to look for. Consider the following factors to make sure you get the perfect dehumidifier to combat mold in your home.

Moisture Removal Capacity

This refers to the volume of moisture that the dehumidifier can remove from the air in 24 hours, typically measured in pints per day or PPF. The actual amount of moisture removed per day depends on the condition and the size of the space. As you may expect, a larger space with a higher moisture content requires a more powerful dehumidifier. However, you must use only the right size for your space to maximize the effectiveness and efficiency.

Tank Capacity

Dehumidifiers collect the moisture in an internal tank. Once the tank is full, you will need to remove it from the unit and empty the water manually. For full-size dehumidifiers, you may have to do this a couple times a day depending on room conditions. For mini dehumidifiers in less humid areas, you may need to empty the tank at least every two days up to a week. It’s important you do this as soon as you can to prevent mold growth inside the machine. 

Coverage Area

You want a dehumidifier that can also cover as much space as you have. The efficiency of the dehumidifier will also depend on the amount of space that it has to cover. Obviously, a dehumidifier can accomplish its task more quickly in a smaller area than a larger one with equal humidity levels. Standard 30- to 50-pint units have recommended coverage areas between 1000 to 3000 square feet. Portable models can cover anywhere from 150 to 500 square feet. 

Additional Features

Modern dehumidifiers usually include the standard auto shutoff feature and indicator light for your convenience. Full-size units offer custom humidity control with a built-in humidistat. You set a target humidity level and the dehumidifier will automatically cycle on and off to maintain this level with little supervision. Most dehumidifiers also feature an on/off timer, multiple fan speeds for maximum moisture removal, and different operation modes depending on your needs. 


Mold naturally occurs in the environment, but you shouldn’t endure its damaging effects when you can simply prevent mold from growing and spreading in your home. One effective way to do this is by controlling indoor humidity with a dehumidifier. For every room size and condition, you’ll find the perfect dehumidifier to help maintain optimal humidity levels.

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