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How to clean a humidifier (and why you should do it today)

Did you know a humidifier can be a breeding ground for bacteria and mold? Neither of those things should end up in your lungs, so knowing how to clean and disinfect your humidifier is essential.
Written by Maria Diaz, Staff Writer

Many of us have been there. Your kid is sick with a runny nose or a cough that wakes you up at 2 a.m. You think maybe the humidifier will help, so you stumble around to get it, refill it, and turn it on, mumbling something reassuring to your kid about trying to go back to sleep.  

Or maybe you like using a humidifier every night for yourself. Personally, I find one helps me sleep better, especially during allergy season. 

But when was the last time you cleaned yours? Have you wondered what kind of bacteria is living in there and ultimately going into your lungs?

How to clean a humidifier

The best thing you can do for your humidifier is keep it clean and use clean water. Simple as that. But knowing how to clean it effectively is important. Always consult the humidifier manufacturer's instruction manual on assembly and cleaning.

Materials needed: 

Estimated time:

  • 15 minutes of cleaning
  • 20 minutes to soak
  • 1 hour to dry

Step 1: Take it apart

Take apart humidifier
Image: Maria Diaz / ZDNet

Take apart the removable pieces on your humidifier. If it has a disposable filter, this is a good time to inspect it and make sure there's no mold growing on it. If there is mold, it's time for a new filter.

Step 2: Wipe down with white vinegar

Wipe it with white vinegar
Image: Maria Diaz / ZDNet

Soak your cleaning cloth or paper towel in vinegar and wipe down all of your humidifier's parts. Clean the base without getting the motor wet. Wipe down the tank and any other pieces.

Step 3: Give the vinegar time to soak

Soak for 20 minutes
Image: Maria Diaz / ZDNet

Carefully add about two cups of vinegar to your humidifier's tank, put the cap on, and swish it around. 

Humidifiers can get limescale buildup pretty much anywhere that comes in contact with water, so you can put the vinegar-filled tank on the base without the filter and let the vinegar soak for about 20 minutes.

Don't turn on the humidifier with vinegar or any other cleaning solution inside it while you are indoors. The resulting fumes can irritate your eyes, nose, throat, and even your lungs.

Step 4: Rinse out the vinegar

Rinse out the white vinegar
Image: Maria Diaz / ZDNet

After the vinegar has soaked in the humidifier, rinse the tank with plenty of water to clear all of it from the machine.  

Step 5: Disinfect the humidifier

Disinfect humidifier
Image: Maria Diaz / ZDNet

To disinfect the humidifier, we'll use bleach. 

It's important to completely rinse out the vinegar as you don't want to mix it with bleach. Now that you have cleaned your humidifier with vinegar, disinfect it with a 10% bleach solution (1:10 solution of 12.8 ounces of bleach per 1 gallon of water). 

Wearing gloves, repeat the process to wipe down your humidifier with the bleach solution to disinfect it. You can use an old toothbrush (that you'll never put in you mouth again) to get into the nooks and crannies. Always avoid getting the motor wet.

Step 6: Thoroughly rinse with water

Thoroughly rinse with water
Image: Maria Diaz / ZDNet

Thoroughly rinse your humidifier with water -- and I mean thoroughly. You don't want any bleach in the unit the next time you turn it on; you or your family could inhale it. 

Fill and rinse the tank several times over and rinse any part that you wiped with the bleach solution. Be careful not to submerge the motor in water. 

If your humidifier has a reusable filter, rinse it a couple times using clean water.

Step 7: Air dry and assemble humidifier

Air dry and assemble your humidifier
Image: Maria Diaz / ZDNet

Dry the humidifier parts to prevent the water from seeping into the base. Let your humidifier parts completely air-dry to remove any moisture before putting it back together.

Reassemble your humidifier once it's dry. Now your humidifier is ready to be refilled with clean water and operated.


Can you get sick from a dirty humidifier?

Unfortunately, yes. Consider you're putting water into this machine and eventually inhaling some of the vapors it produces. We know moisture is a breeding ground for bacteria and mold, so it's only natural that it could make you sick.

Several studies have noted what has been called humidifier lung and humidifier fever, which are pulmonary inflammation and/or flu-like symptoms with fever caused by bacteria, mold, or yeast that could call your humidifier home. So the importance of keeping your humidifier clean goes beyond simply having a clean home in general. It's about your health and that of your family.

How can I keep my humidifier clean?

It's important to let your humidifier dry completely every now and then between cleanings. This will prevent moisture from sitting in the inner parts of your humidifier, effectively avoiding bacteria growth. So if you use your humidifier at night, empty it out in the mornings, give it a rinse, and let it completely air-dry for about 45-60 minutes, this will help keep your humidifier clean.

Aside from letting your humidifier air-dry, you may want to add a water treatment to prevent bacteria growth and mold. These come as a liquid bacteriostaticdrops, or even a fish.  

Do I need to add clean water to a humidifier every time I use it?

Every time you refill your humidifier, empty out the tank and base completely and rinse the tank before refilling it. Refilling the tank by adding fresh water to the water remaining in it potentially can leave any bacteria that has taken hold of your old water in your humidifier. A good, quick rinse is a simple way to prevent biofilm buildup as well.

Is it okay to use tap water in a humidifier?

If your tap water is safe for drinking, then it should be fine to use in a humidifier. A humidifier with a filter provides a layer of cleansing for the tap water. 

With filter-less humidifiers, I prefer using filtered or distilled water. This helps prevent limescale buildup, which can happen with tap water, and helps keep the humidifier cleaner and running smoothly. 

How long does a humidifier filter last?

A humidifier filter typically lasts three to six months, depending on frequency of use, the care you give it, and the type of water used. 

A filter may have a brown tinge when you take it out, but many manufacturers say this is normal. It is important to always follow the filter manufacturer's instructions on when to replace it. 

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