Why Does My Humidifier Smell?

why does my humidifier smell

If there’s one household appliance that helps improve your quality of life during the dry, cold winter months, it’s a humidifier. These machines can help keep your skin from getting dry, help with nosebleeds, and even reduce your snoring.

Humidifiers can emit some weird smells sometimes, and it’s not pleasant when your room smells musty, sour or even worse, like wet dog, fish or urine. So, if you’ve wondering, why does my humidifier smell, it could be from a number of reasons. Using tap water, or skipping regular maintenance are the two most common.

I’ve covered the typical humidifier smells, reasons why, and how to get rid of humidifier smells in the article below.

Why Does My Humidifier Smell Musty?

If your humidifier releases a musty odor, it is caused by bacteria growth in stagnant water inside it. Stagnant water is a breeding ground for fungus and mold.

The smell can be from the filter if the humidifier has one. You may also see black or green discoloration in the device’s reservoir and water tank.

This discoloration will make the water tank fuzzy. Besides the musty smell, these germs can spread through the mist and potentially cause lung problems like the flu.

How to Fix a Musty Smelling Humidifier

You will need a cleaning agent such as vinegar or bleach. Add one teaspoon of the cleaning agent you use per gallon of water. It will help if you leave the solution to rest for an hour and then use it to wash the humidifier.

Cleaning with Vinegar

  1. First, unplug the humidifier and empty out any water that is still in it.
  2. Add 1/4 cup of white vinegar and 3/4 cup clean water inside the humidifier water tank.
  3. Scrub it gently with a soft bristle brush.
  4. Drain the vinegar and water solution, and rinse with clean water.
  5. Refill the humidifier water tank with a solution of water and vinegar.
  6. Leave it to soak for 30 minutes before draining and rinsing with warm water.
  7. Refill your humidifier with distilled water and run as usual.

Cleaning with Bleach

Cleaning with Bleach: The cleaning process is similar to vinegar, except you’ll use a bleach solution and water from the beginning. To get rid of the bleach, you will also run clean water through the humidifier until it is clean.

Why Does my Humidifier Smell Like Wet Dog?

humidifier smells like wet dog

It’s common to use a humidifier and forget to clean it, which will cause it to emit that wet dog smell. The smell is a telltale sign that the unit’s components are dirty. It would be best to stop using the humidifier if it’s in that condition. If you keep using the device, it could spread bacteria into your living space, which could cause lung infections.

Clean your humidifier using white vinegar and water or bleach and water solution. Use a q-tip dipped in white vinegar to clean around any seals into corners, crevices, or small parts. Rinse well and refill your humidifier with distilled water.

Why Does my Humidifier Smell Like Pee

A humidifier can smell urine due to mineral buildup. These minerals appear as grey or white deposits in the humidifier’s drain, water tank, or reservoir. When water evaporates from the humidifier’s tank, magnesium carbonate and calcium are left behind. This forms a deposit of minerals. This mostly happens if you use tap water from a hard water region.

Some essential oils can make a humidifier smell like urine. Essential oils corrode the plastic parts of your humidifier and produce that smell. I have covered this further in a post on using essential oils in your humidifier.

Additionally, fungal spores can also result in a strong urine odor. This happens if you don’t refill the humidifier regularly.

The best way to solve this problem is to empty the humidifier and descale it before refilling it with distilled water. It’s best to avoid tap water if you’re in a region with hard water. Always use distilled or demineralized water.

Cleaning the mineral deposits is known as descaling and entails soaking the tank and reservoir to soften the deposits. Soaking can take a few hours or overnight, depending on how bad the scaling is. You will then use a soft brush and vinegar solution to scrub the humidifier. After that, thoroughly rinse it, then leave it to dry before refilling.

Why Does my Humidifier Smell Like Fish?

humidifier smells weird

The humidifier will smell like fish if mold or mildew accumulates in the unit. In some cases, the smell can be due to the burning of some electrical components.

Switch off the humidifier immediately and empty out the water. Check all electrical components and the inside of your humidifier.
Clean the humidifier tank using white vinegar and water or bleach and water solution. Rinse well and refill with distilled water.

Other Smells Coming From Your Humidifier

Other common smells coming from your humidifier might be sweet, sour, burning or plastic type smells. Here are the common complaints about smelly humidifiers and how to freshen them up.

Burning Smell

A burnt or burning smell from a humidifier means that it’s overheating. This overheating can be due to a lack of water in the tank, especially in warm mist humidifiers that don’t have an auto shut-off feature. Additionally, putting the device close to a heat source can cause the unit to emit this burnt smell.

The solution to this smell is to check the water level and refill it if necessary. Disconnect your humidifier from its power source, disassemble it, and let it cool. After the tank has cooled, fill it with distilled water and put it back together to keep using it. But before that, ensure that the unit isn’t near a heat source that could burn the plastic components.

New Humidifiers

New humidifiers can often emit a plastic smell due to off-gassing. Gas trapped in humidifier parts during their manufacture is released during this process. The gas isn’t hazardous, provided the manufacturer used safe products to make the unit.

An off-gassing smell should dissipate in a few days. If you are concerned, double-check the humidifier’s internal components to ensure everything is working correctly. If the smell persists after a few days, contact the manufacturer or place of purchase.

Humidifiers That Smell Like Vinegar

Your humidifier will smell like vinegar if you use more than a 5% acetic acid solution. As effective as vinegar is as a cleaning solution, because of its lower toxicity than other commercial cleaning agents, it’s hazardous in distilled fume form. So, if you want to “clean the air,” it’s best not to put vinegar in the humidifier.

The solution to this smell is to clean the humidifier thoroughly. To do so, you will unplug the unit and empty it. You will then one part hydrogen peroxide with 4 parts water. Leave this to soak in the humidifier for 30 minutes. Use this solution to clean the inside of the water tank and all available parts of your humidifier.

Rinse the humidifier thoroughly after cleaning and refill with distilled or demineralized water.

humidifier smells

Sweet Smelling Humidifiers

A sickly sweet smell from a humidifier is a sign of mold accumulation inside the unit.

Clean the humidifier using white vinegar and water or bleach and water solution. Scrub the inside of your water tank well and use a q-tip to get into cracks and crevices. Rinse well and refill with distilled water.

My Humidifier Smells Like Chlorine

Chlorine is another typical smell humidifiers emit. Heavily chlorinated tap water can be the culprit. This is because as the water vaporizes, chlorine is dissolved in the vapor. A chlorine smell from a humidifier is unlikely to be the more harmful chlorine gas. More information on chlorine gas can be found on the CDC website.

Empty out the humidifier, dry the inside and refill it with distilled or demineralized water. You can also use a mixture of bleach and water or vinegar and water to clean the inside first.

My Humidifier Smells Sour

An unpleasant sour smell is caused by bacteria buildup in the humidifier. This smell of fermentation is a sign that you haven’t cleaned and refilled the humidifier in a long time, and bacteria have grown in the water. You may also notice mold starting to grow, cloudy water, or discoloration.

Clean the humidifier tank thoroughly using vinegar and water or hydrogen peroxide and water.

Frequently Asked Questions About Smelly Humidifiers

dyson humidifier musty smell

Why Does My Humidifier Make My Room Stink?

If your humidifier emits a musty smell that makes your room stink, you need to give it a good clean. Clean with tap water and a small amount of vinegar, bleach, or hydrogen peroxide. Change any filters your humidifier has. Refill with distilled water only to cut down on cleaning and maintenance.

How Do I Freshen My Humidifier?

Hydrogen peroxide (3%) is a disinfectant that will help keep your humidifier fresh. Use 1/4 cup of hydrogen peroxide and 1 cup of water. Let it sit in the the humidifier for 30 minutes (don’t run the humidifier). Use the solution to clean the rest of the tank and inner parts, then rinse with clean water. Only use distilled water in your humidifier for the best outcome.

Can You Use Tap Water With a Humidifier?

Tap water isn’t recommended for use in humidifiers due to the mineral build up causing calcification and poor mist output. Tap water can also harbor bacteria, causing mold buildup inside the tank. Use distilled water in your humidifier for the best results.

Your Humidifier Shouldn’t Smell

If your humidifier starts to smell, it is most likely a sign some maintenance is needed. Tap water is the most common culprit for mineral buildup and bacterial growth. You must change the humidifier water more frequently, generally every 3 days (maximum), daily changing is often recommended.