Why Does My Humidifier Smell: A Simple Guide

Assembling a humidifier

Humidifiers are designed to help us maintain comfortable humidity levels inside our homes. This keeps our skin supple and can reduce symptoms like dry throat and runny nose during the winter months. But what should you do if your humidifier starts to smell? Keeping your humidifier clean is the easiest way to avoid harsh smells and continue using your humidifier as usual.

If you’re wondering “Why does my humidifier smell and is it a hazard to my health?”, these are both important questions to ask and we’re here to help.

Reasons Your Humidifier Smells

Here are four common smells and their causes:

Musty Smell = Mold

Why does my humidifier smell musty? This is the most common smell many homeowners experience and it’s due to mold growth in the stagnant water. As water sits in the humidifiers tank, it can develop mold and mildew which leads to a musty smell.

Keep in mind that you’re providing moisture to the air using this water to enhance your indoor air quality. If the water has developed a layer of mold, you can be putting mold spores into your home which can cause serious issues for people with allergies or respiratory issues.

To tackle mold-related smells, regular cleaning and maintenance are vital. Always empty and dry the water tank when the humidifier is not in use.

Yeast Smell = Bacteria

You may notice a yeast or sour smell coming from your humidifier and this is due to bacteria growth. Bacteria thrives in moist environments and you’re likely to experience this if your humidifier has a filter that hasn’t been cleaned or replaced often enough.

All of the dust and debris that gets caught in the filter is then moisturized from the humidifier which causes bacterial growth. To prevent this from happening, be sure to clean and change filters according to the humidifiers manufacturers instructions.

Urine Smell = Mineral Deposits

If you have hard water that contains high concentrations of calcium and magnesium, you might notice a urine smell coming from your humidifier. While it’s unpleasant, it’s not as harmful to your health as the previous two issues.

To combat mineral deposits, use distilled or demineralized water in your humidifier. These types of water have had most of their mineral content removed, reducing the chances of deposits forming.

Burning Smell = Electrical Problem

If you notice a burning smell, you’ll want to turn your humidifier off immediately. This likely has nothing to do with the water or moisture but instead, is a sign of an electrical problem with the components inside the unit.

The humidifier might be overheating which can pose a fire hazard so you’ll want to unplug it, give it some time to rest, and try again. Keep a close eye on the humidifier and if you notice the smell again you’ll want to contact the manufacturer or take it back to the store if you purchased it recently.

Best Way to Clean a Humidifier

Now that you understand all the humidifier smells and issues associated with them, let’s talk about the best ways to clean your humidifier to prevent these issues from happening.

  • Unplug the humidifier and disassemble it according to the manufacturer’s instructions.
  • Empty any remaining water from the tank and base.
  • Wash all removable parts with mild soap and warm water. Use a brush or sponge to remove any residue or buildup.
  • For stubborn mineral deposits, use a mixture of white vinegar and water to soak the affected parts. Rinse thoroughly afterward.
  • Wipe down the exterior of the unit with a damp cloth.
  • Allow all parts to air dry before reassembling the humidifier.


Here are some of the most frequently asked questions about humidifier smells.

Why does my room smell weird after running the humidifier?

If you notice strange smells in your room after running a humidifier, you’ll want to check the reservoir to make sure there is no mold or mildew. Check your filters, clean them, and replace everything to prevent this problem.

Why does my cool mist humidifier smell like pee?

Mineral deposits from hard water are the most common causes of a pee smell. Use distilled water and clean your unit to prevent this.

Should a humidifier smell at all?

Ideally, a humidifier should not emit any noticeable smell. If you experience odors, it indicates a problem that needs to be addressed, such as mold, bacteria, or mineral buildup.

Final Thoughts

Humidifiers are an important part of maintaining optimal indoor air quality but if your humidifier smells, it’s likely doing the opposite. Let us help with your indoor air quality today!

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