Do Dehumidifiers Remove Mold & Mildew?

Thomas King

Mold and mildew growth is a serious problem. In addition to causing damage to your home, including peeling and wood rot, mold can cause significant health problems, including eye and skin irritation and asthma attacks and other respiratory complications.

Dehumidifier attached to side wall in room

To prevent these problems, it's important to take care of infestations early.

Mold and Mildew

Mold is a microscopic fungus that requires moisture, warmth and organic material to grow; some types of mold produce mildew in damp, warm and poorly lit places. When mold and mildew form, the appearance of the substrate on which they grow generally takes on shades of green, black, white or yellow. Molds can be fuzzy, but mildew tends to be thinner and merely cause discoloration.


Dehumidifiers help prevent mold and mildew from growing in your home because they remove moisture from the air. However, a dehumidifier will not remove mold and mildew that has already formed. To effectively prevent mold and mildew growth, the University of Missouri Extension Service recommends keeping the relative humidity in your home between 35 and 55 percent. Many dehumidifiers feature a relative humidity gauge, also called a hygrometer, that can help you accomplish this. Relative humidity gauges can also be purchased separately at most hardware stores.


You can remove mold and mildew from hard surfaces using a stiff brush and a mixture of detergent and water. If mold has overtaken an extremely porous surface, such as paper or drywall, the substrate on which it's growing should be discarded. Before cleaning up mold, put on long rubber gloves, eye protection and an N-95 respirator mask. These items will help limit your exposure.


The key to preventing fungus growth is controlling the moisture. In addition to running a dehumidifier, you should increase ventilation and air circulation in the home and manage external runoff (such as that from gutters) and other potential sources of water intrusion. In addition, you should install an exhaust fan in high-moisture areas, such as bathrooms and kitchens.