Humidifier Mold Prevention

Suzanne Alicie

Because a humidifier incorporates moisture into the air in your home, it is also an ideal home for mold. Water in a closed container with heat from the motor and a fabric or foam filter creates an environment that mold will thrive in.

There are several ways to prevent mold from growing in your humidifier and spreading through your home when it becomes airborne. Many of these steps are simply basic humidifier maintenance.

Cleaning Your Humidifier

It is important to clean your humidifier at least once per month. Empty the humidifier and wash it with extremely hot water and either vinegar or chlorine bleach to kill mold spores. While you are washing the humidifier, remove the fabric or foam belt that lifts and cycles the water, and wash it in hot water and vinegar as well. This will kill any existing mold spores and also eliminate hard-water deposits from forming in your humidifier. In between the monthly cleanings it is wise to remove and wash the belt weekly, as the texture of the belt allows many spaces for mold to form and grow.


When you fill your humidifier, simply adding a cup of white vinegar to the well will help prevent mold from growing. Vinegar is a natural antimicrobial and antibacterial product that will not harm the various parts of the humidifier while it kills mold spores that it comes in contact with.

You can also purchase humidifier tablets to drop in that will do the same thing for a higher price. It is almost always cheaper to use natural products you have around the home.

Some other additives include hydrogen peroxide, tea tree oil and even a small amount of chlorine bleach. However, bleach can damage hoses when it is exposed to them for long periods of time.

Storing the Humidifier

Humidifiers aren't often used year-round. If not emptied and dried properly, mold can grow in the humidifier while it is not being used. When you are finished with the humidifier for a while, always clean it well and allow it to dry completely, especially the pad. Sit an opened box of baking soda inside the humidifier before placing the lid on and storing it. Baking soda will absorb moisture and prevent mold from forming while the humidifier is not in use.