How to Clean a Humidifier

Most homes have humidifiers, especially when the weather is dry. Excessive humidity is uncomfortable (it makes people sweat more), but equally, humidity that is too low can cause discomfort. Dryness of skin, irritation to eyes and sinuses, and other unpleasant conditions can result.

Humidifiers are, therefore, a welcome addition to a home. Most humidifiers last for many years, but it is important to keep them well-maintained. Without regular cleaning, a humidifier would accumulate dust and dirt, or even worse contaminants such as mold, mildew and limescale. If a humidifier has enough of such particles, especially in its reservoir tank, air vents, or misting outlets, it will end up polluting the room. What started as an attempt to improve the conditions of a home may end up making it unhealthier.

A clean humidifier is a must. The good news is that cleaning is easy! It doesn’t require more than ordinary household items: some white vinegar, lots of clean water, a towel, cloth and sponges. Experts recommend that humidifiers are cleaned lightly every 3 days and deeply cleaned once every 2 weeks.

Once equipped, here is a simple step-by-step guide to cleaning a humidifier.

1. Unplug the Humidifier
It’s not sufficient to turn off the power. It should be fully unplugged from the wall socket for safety reasons.

If the humidifier has a heating element (most models that emit warm air or mist have one), then it is recommended to let the unplugged unit sit and cool for 30-60 minutes before proceeding to the next step. Again, this is for safety – it will prevent any burn injuries.

2. Rinse the Air Filter
The next step is to check the location of the air filter (the user’s manual may help), then follow the instructions to remove it from the unit. Clean the filter by running cold tap water over it. Make sure to turn over the filter so that all its surfaces are cleaned. Allow the air filter to dry naturally by leaving it on a clean cloth or towel.

Note that cleaning or chemical solutions should not be applied to the air filter, or it could likely damage the filter.

It may be necessary to replace the air filter entirely if it looks worn or damaged. Most hardware stores would carry air filter parts for a wide range of humidifier models. Alternatively, look online.

3. Clean the Reservoir Tank
Take out the tank from the unit. Empty the liquid contents into a drain or sink.

Next, fill the tank to half-full with the white vinegar, taking care to swirl or pour the vinegar so that it covers the bottom and insides of the tank fully. Leave the vinegar to soak the tank for at least 60 minutes.

This is an effective cleaning method because vinegar is acidic and will eliminate limescale and other minerals. In fact, vinegar will remove small amounts of mold and mildew.

For very dirty tanks, a sponge should be used to scrub the insides until no traces of dirt can be seen. Vinegar can be added to the sponge for a stronger scrub. Cotton wool or swabs can be used to get to the corners of the tank.

Pro tip: Adding a small amount of uncooked rice to the vinegar in the tank and shaking the tank will help dislodge stubborn dirt particles trapped in corners or edges. The rice and vinegar mixture creates a slurry that essentially exfoliates the tank.

Do not use other chemical solutions to clean the reservoir tank. Vinegar is a natural substance and, therefore, safe for people. Stronger cleaning solutions may contain harmful chemicals and leave a residue in the tank. These chemicals may be expelled by the humidifier back into the room and pose a health hazard.

4. Rinse Out the Tank
Empty the tank of excess vinegar, then rinse thoroughly with tap water. Several rounds of rinsing are typically required to get rid of the last traces of vinegar, resulting in that clean smell.

5. Clean the Humidifier’s Frame
With a clean reservoir tank, the next step is to wipe down the outside of the humidifier. Dab a clean sponge in some vinegar and water, then wipe the frame. Most people pay extra attention to the joints or edges of the unit, such as around the knobs, controls, or user displays.

Use another dry cloth to wipe down any excess water.

6. Re-assemble the Humidifier
Now it’s time to replace the dry air filter back into the unit. Fill the reservoir tank with clean water, then power up. Enjoy a clean, well-functioning humidifier!


Disinfecting a Humidifier
Once every 2 or 3 times a humidifier is cleaned, it should be thoroughly disinfected. This will ensure that mold and other harmful particles do not make the humidifier their home.

Here are 3 methods to disinfect. They use bleach, vinegar, and peroxide, respectively. However, these cleaning solutions should not be mixed together. Doing so may inadvertently create harmful fumes.

Method 1: Bleach
This is a very strong chemical but necessary if the humidifier is extremely dirty or has lots of mold growing inside. Bleach will effectively kill any microscopic particles, but too much bleach can cause health issues.

Fill up the reservoir tank with regular tap water. Add a few teaspoons of bleach – no more. Let the mixture sit in the tank for about 60 minutes, but not much longer, as too much bleach may cause permanent damage to the tank.

Empty the tank and rinse thoroughly with tap water, taking care not to get bleach on exposed skin. (If this happens, seek medical attention immediately.) Dry the tank and replace in the humidifier.

Method 2: Vinegar
Mix one cupful of vinegar into a reservoir tank full of water. Replace the tank, then run the humidifier as usual for about 60 minutes. This will allow the vinegar to clean not only the tank but the air vents and misting outlets as well. However, take care to run the humidifier outdoors – running it indoors with a vinegar solution will make the home smell like vinegar!

Once the unit has run for long enough, turn it off and unplug the unit. As before, empty the tank, rinse thoroughly with tap water, dry the tank with a cloth and replace it in the humidifier.

Some people may be tempted to add essential oils into the reservoir tank, thinking that it may help to eliminate or mask the smell of vinegar. Do not attempt this unless explicitly allowed in the user manual. Essential oils are another substance that may permanently damage the unit.

Method 3: Peroxide
This is a mild version of bleach but often works just as well.

Fill the reservoir tank with peroxide, taking care to cover the insides and bottom of the tank thoroughly. Leave it to sit in the tank for 60 minutes, then pour it out. Rinse the reservoir tank with ordinary tap water.


The Importance of Maintenance
Cleaning the humidifier isn’t the only way to maintain it. Indeed, most people clean their humidifiers only occasionally. However, frequent maintenance is important, and there are a few simple steps that should be done on an almost daily basis.

Empty the Tank
It may be tempting to let the water sit in the reservoir tank and just re-use the water. But it’s a bad idea, especially if the humidifier is not constantly running. Water that sits in the tank tends to grow mold and other bacteria, posing a health risk. Tanks should be emptied daily, or at most on alternate days, to be safe.

Avoid Excessive Moisture
Humidifiers sometimes create too much humidity around them, causing mold and mildew in the reservoir tank or other inside parts. Just turn off the unit when possible to avoid excessive moisture and health problems.

Store It Properly
Many people use their humidifiers only during the winter when the air is particularly dry. During the off-season, it is important to store it properly. This means emptying the tank, drying every part of the unit, and cleaning it to eliminate any bacteria.

The humidifier should also be cleaned when it is taken out of storage.


Frequently Asked Questions

How To Remove Limescale or Calcium Deposits?
This is a common problem. Calcium or limescale deposits come from the mineral content of tap water, especially “hard” water. The vinegar solution recommended is typically effective in removing such deposits.

How Quickly Does the Air Filter Dry?
This depends on the humidity of the home. Unfortunately, the more humid the air is, the slower the air filter will dry. But typically, it takes only a day for an air filter to dry completely. Just be sure to check that the filter is completely dry before replacing it in the humidifier.

Can a Dishwasher be Used to Wash the Humidifier?
No. This is especially true of electrical components. Some manufacturers state that their product is “dishwasher safe” – these are exceptions rather than the rule. Even for such units, it would be safer not to do so.

When Running the Humidifier to Clean It, Should Vinegar be Used?
No. Vinegar will damage the air filter. Be sure to remove the filter before filling the reservoir tank with vinegar and running the unit.

The Humidifier Still Smells Funny After Cleaning – Can It Be Used?
It’s best to replace such a unit. The funny smell could be residual mold or bacteria in the inside parts of the humidifier, which cannot be removed even after deep cleaning with bleach. This means the humidifier is no longer safe to use.

There’s Colored Residue In The Humidifier – What Is It?
This is most likely mold. There are various forms of mold, in colors ranging from black to brown to pink. If there is colored residue in the humidifier, it is important to deep-clean the unit with bleach.

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