How to prevent mold from forming in a humidifier

When dry winter air gets uncomfortable, many homeowners turn to humidifiers to increase the levels of humidity in their homes. But while it may be helpful to use the device, it can also be harmful in specific aspects.

Depending on how often you clean your humidifier and the type of water you pour in it, chances are you are breathing in harmful microorganisms like mold. You need to figure out how to prevent mold in the humidifier before it can cause any adverse health effects.

Humidifiers come in different types. Some of these include evaporators, ultrasonic, and impeller humidifiers. Besides, some home heating and air conditioning systems have in-built humidifiers designed to humidify a house. Apart from the steam vaporizers, which use electricity to create steam, the rest of the devices can be breeding grounds for mold.

4 ways to prevent mold in your humidifier

Luckily, you can keep your humidifier from molding using different methods.

1. Use white distilled vinegar

One of the best ways of protecting a humidifier from molding and scaly build-up is to add white distilled vinegar into the device’s water chamber.

  • Empty the water from the humidifier’s chamber
  • Add some fresh water, either distilled or demineralized, into the chamber
  • Pour one cup of white distilled vinegar into the water
  • Let it run until the tank is empty
  • Repeat the process at least once a month

Vinegar is the best natural humidifier additive to prevent mold because it has antimicrobial and antibacterial properties. It is also safe to use and will inhibit the growth of mold in the device.

2. Use humidifier cleaning tablets

Many humidifier cleaning tablets act as demineralization agents. They are useful for removing minerals that cause white dust and purifying the water in the chamber to prevent the growth of mold.

  • Discard the water in the device chamber
  • Add fresh distilled water
  • Drop the tablets in the water

Read the packaging to know the number of tablets you should drop in the water or how to use them. The tablets will dissolve in the water and remove microbial build-up and essential oil residue. You can find the best humidifier cleaning tablets here.

3. Clean the humidifier weekly and regularly

The easiest way to prevent mold from forming in a humidifier is to clean it thoroughly every week or regularly. When cleaning the device:

  • Empty or discard the water from the chamber.
  • Rinse it using hot water. You can also add hydrogen peroxide, white distilled vinegar, or tablets to rinse the device.
  • Scrub all corners of the machine using a sponge or bristled brush to get rid of mold build-up or scales.
  • After scrubbing, rinse it again using hot water.
  • Dry your unit in direct sunlight or air-dry it before you assemble it.

The next step is to add some fresh distilled water and let the humidifier run. If your humidifier smells bad, use these strategies to eliminate the odor.

4. Do not use tap water in a humidifier

Many humidifiers work by separating, splitting up, and expending water and mineral particles. The process form white dust, which is a mineral residue that can spread around a house and in the device’s water tank. This dust usually occurs if you use tap water.

It is not advisable to add unfiltered tap water into the unit because the mineral deposits will cause bacterial and mold growth. Therefore, use purified, distilled, or demineralized water in the humidifier.

If you don’t have a way to purify, we recommend using CO-Z water distiller. You can also find a good selection of water distillers here at Amazon.


The best humidifier mold prevention step you can take is to clean the unit weekly and regularly. You can also add humidifier tablets into the device’s water chamber or add white distilled vinegar or hydrogen peroxide to inhibit the growth of mold.

It is not advisable to use unfiltered tap water into the tank. Instead, use demineralized or purified water to prevent mold from forming in a humidifier.