Humidifier Cause Mold? Symptoms and Prevention

When we have trouble breathing, sleeping or fallen sick, we turn to humidifier. It is a perfect night companion but beware, poor maintenance will lead to the widespread of mold and its pal. Inhaling into these airborne microbes will lead to many preventable health complications. So how can a device that is designed to disperse moisture can end up being the breeding spot of mold? What can you do to prevent mold and other microorganisms from spawning inside a humidifier water tank?
Short answer
Humidifier requires cleaning every 3-7 days. Choose warm-mist type if you want a relatively mold free humidifier.


Mold in Humidifier: Real or Myth?

Mold in a humidifier can make you sick. A dirty humidifier (cool-mist or warm-mist) will have mold growing it that can become airborne contaminants during humidification. As warned by Consumer Product Safety Commission and EPA, a humidifier that contains mold will actually do more harm to our health particularly for people suffering from asthma. Most mold and bacteria patches can be spotted in the water tank. However, mold and bacteria accumulation can also happen on the ventilation, filter or fan blades that are hidden inside. If your humidifier is part of a HVAC system, checking on mold infestation can be tricky without professional help.

What Happens If You Don’t Clean Your Humidifier?

If you continue using a dirty humidifier, you’re at risk of falling sick from exposing to mold, bacteria, or germs. White dust, fungi, and germs will be released into the air together with the mist. When we inhaled the allergens into our body, the harmful microbes will begin infecting our nose, lungs, and respiratory system. At this point, one may experience allergy reactions from the common flu, cough to the more severe hallucination, and heart failure.

Mold in Humidifier Symptoms

  • Stuffy nose with flu
  • Postnasal drip cough/ Wheezing
  • Bloodshot/ dry eyes
  • Itchiness on throat, skin, and eyes
  • Rashness/ Eczema
  • Chest tightness
  • Breathing Difficulty
  • Headache, Dizziness
  • Forgetfulness
  • Constant joint pain

Can a Humidifier Cause Mold In a Room?

If a humidifier continues to supply moisture to a room with excessive wetness, it can cause mold to build up rapidly. Mold flourishes in a high humidity environment and will start spreading on porous objects. From wall, ceiling, windows, windowsills, bathroom, door, to wooden furniture, nothing is spare. So do not operate a humidifier if the room dampness level is high and make sure the humidifier is clean.

Humidifier Mold Prevention Tips

If you notice your humidifier is starting to give in to mold, it’s time to perform some cleaning. In general, cool mist humidifier (evaporative or ultrasonic) requires maintenance every 3-7 days. On the other hand, warm mist humidifier would require less maintenance due to the nature of its heating elements. If you decided to keep the humidifier back to storage for future use, make sure the unit is thoroughly clean and dry especially in the reservoir. Store it in a dry location to prevent mold infestation.

Below are the steps to get mold out of a humidifier without any fuss.

How to Clean Humidifier Mold

  • First thing first, unplug your humidifier before proceeding with the cleaning. Wear rubber gloves to avoid direct contact with mold.
  • If the water bucket is full, empty out the remaining water in the reservoir.
  • Apply a few drops of 3 percent hydrogen peroxide or white distilled vinegar and mix it up with water. Pour the natural solution into the bucket and let it soak about 10-20 minutes. Empty out the remainder solutions.
  • Use either a toothbrush, sponge or scrubber and scrub all the surfaces with mineral build-up. Once the mold and mineral patches fall off, rinse the bucket and flush out the remaining residues.
  • Repeat the mixing and scrubbing process if there are still leftover residues.
  • Use a dry cloth and start wiping both inside and outside of the water bucket. After that, let it air-dry before refilling the bucket with only distilled water.
  • Resume back the humidifier operation and let it run for at least 10-30 minutes.

Humidifier is a highly popular home appliance during winter where the indoor air is dry due to the constantly running heater. It helps increase the moisture level of your home so the air is much more breathable for everyone. Nevertheless, over humidifying can be bad for you and your home as the warm temperature and damp air is perfect for mold, dust mites, and pest. We recommend keeping the relative humidity level between 30-50 percent where the air is clean without the risk of mold growth. It will also discourage the spread of bacteria and viruses due to the heavier air.


Max Fernandez

A humidifier distributor with more than 11 years of experience in the field, Max Fernandez is no stranger to the moisture-capturing machine. You can catch him here reviewing humidifiers and preaching on the importance of perfect humidity.