Can a Dehumidifier Kill Mold?

Dehumidifiers are very handy tools used for reducing humidity in our homes. Stronger ones can even be used for larger, higher-scale water damage drying, like after flooding.

Many homeowners who have high humidity in their homes and subsequent mold problems often ask if their dehumidifier can kill that mold.

It’s convenient to think that way. You just turn the machine on and let it do the deed. However, it’s not that easy.

Today we’ll cover whether dehumidifiers can kill mold and other things you should know regarding the topic.

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What Do Dehumidifiers Exactly Do?

Dehumidifiers are used to regulate and reduce the level of humidity in most types of indoor spaces, including homes and offices.

They work by drawing in the air first. Once the air is inside the device, it undergoes cooling and condensation.

The incoming air passes over cooling coils, causing it to cool down. As the air cools, the moisture it carries condenses into water droplets.

The collected water is then directed either into a reservoir within the dehumidifier or through a hose to a drain. This water represents the excess moisture that was originally present in the air as humidity.

Before releasing the dehumidified air back into the room, it undergoes a reheating process. This is done to ensure that the air doesn’t become too cold, maintaining a comfortable temperature within the indoor space.

The benefits of using dehumidifiers extend beyond comfort. They minimize the presence of dust mites, allergens, mold, and other struggles.

But can they actually kill mold?

We’ll get to that, but first…

Wait, What is a Humidity Level?

For starters, humidity refers to the amount of moisture in the air, and maintaining an optimal humidity level is crucial for a comfortable and healthy living environment.

What is an Optimal Humidity Level?

Between 30% and 60%, plain and simple.

How Do I Know My Humidity Level?

You can simply get a hygrometer or use a more barebones moisture measuring method like the “soap and squeeze” method.

Can Dehumidifiers Actually Kill Mold?

Simply put, no. Dehumidifiers don’t kill mold. They are simply used to prevent it.

Mold grows whenever there’s a moisture source. Once it grows, it needs to be properly removed and the affected area disinfected. 

You need to kill mold’s roots, often coming from inside the walls. You also need to get rid of the actual moisture source that caused humidity levels to be this high.

It might just be the weather or a leak. Either way, that has to be handled.

How is Mold Killed?

You first need to understand how mold survives; otherwise, mold will just keep coming back.

Firstly, moisture is a critical factor. Mold “colonies” (which is what mold people refer to as mold) thrive in wet environments, and they often develop in areas with water leaks, high humidity (so above 60%), or just inadequate ventilation.

To effectively kill mold colonies, addressing and eliminating the source of moisture is paramount. This may involve fixing any leaks, improving ventilation, and using, you’ve guessed it, dehumidifiers to reduce humidity.

Additionally, mold colonies need a nutrient source to sustain themselves. Molds are capable of breaking down and consuming all organic materials, such as wood, paper, fabric, and even some building materials.

This is why mold can’t be just brushed off. If it grew on, for example, your drywall, you need something that will penetrate the surface and kill all the mold inside.

Vinegar, particularly white vinegar, is a natural disinfectant. Undiluted white vinegar can be sprayed directly onto the moldy surface. After letting it sit for an hour, the area is scrubbed and then wiped clean.

The reason vinegar is great is because it penetrates deep beneath the surface, which is exactly what you need.

What Do I Need Dehumidifiers For Then?

Dehumidifiers are used to prevent mold, not to kill it. It’s essential for a room to be dry so that mold does not come back.

Remember, mix moisture with organic matter and you’ve got mold. Dehumidifiers help keep the moisture out. They are also great for reducing allergens. 

Dust mites, pests like cockroaches, silverfish, and other nuisances also show up when there’s more moisture than needed. If you’ve got allergies or asthma, dehumidifiers can be very helpful to you. An appropriate humidity level positively impacts respiratory health.

Have in mind that high humidity can make your body feel hotter. This can cause you to feel dehydrated and fatigued. You may even get muscle cramps.

So, keeping your rooms dry is quite handy if you’re prone to this.

How to Choose a Dehumidifier?

Great question! 

Determine the square footage of the space where you plan to use the dehumidifier.

Dehumidifiers are typically rated by their pint capacity, which represents the amount of moisture they can remove in a 24-hour period. 

Choose a capacity that matches the size of the room or space. Small-capacity models (around 30-40 pints) are suitable for smaller rooms, while larger-capacity models (50-70 pints or more) are ideal for larger areas or high humidity conditions.

Of course, this is a pretty brief explanation. For more details, read our guide on choosing a dehumidifier.


Wrapping up! Dehumidifiers are really handy tools. However, they can also be pricey, so make sure you get them only if you need them.

If you need more help with water damage, check out some of our other posts or connect with a restoration pro near you!

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