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Can You Use A Humidifier Without A Filter

Can You Use A Humidifier Without A Filter?

More and more people opt for using a humidifier at home. It is such a simple but effective household appliance that can relieve many conditions in dry and cold climates.

Some humidifiers work with a filter, and some don’t. Therefore, people may be looking for different answers when they ask if they can use a humidifier without a filter.

Simply put, using a filterless humidifier is perfectly fine as long as you clean and disinfect it regularly and fill it with distilled water. For filtered models, you can temporarily run it without a filter but should get a filter replacement as soon as possible.

This post will explore more about humidifier filters and how to operate a humidifier when it lacks a filter replacement. Let’s dive in!

Do all humidifiers have a filter?

Do all humidifiers have a filter

No, not every type of humidifier has a filter. So if you find your newly got humidifier doesn’t come with a filter or have no place to put the filter, it is possible that it is just a filterless humidifier.

Ultrasonic humidifiers usually don’t have to use a filter. They use a diaphragm to break down the water into tiny moisture molecules. The mineral buildup and germs will also disperse into the air if you fill it with tap water.

Warm mist humidifiers also don’t have an embedded filter. They make use of heating elements to kill the molds and bacteria and turn the water into steam vapor. 

Evaporative humidifiers and drum-style and flow-through furnace humidifiers usually come with a filter. When using these types of humidifiers, you will need to replace the filter every two to three months or one or two times every heating season. 

You can check here to know more about the differences between the filterless model and the filtered model.

Can you run a humidifier without a filter?

Yes, you can. Running it without a filter is just what you need to do if you have a humidifier that isn’t meant to work with a filter, like an ultrasonic humidifier or vaporizer. 

If you have a humidifier that is designed to work with a filter, running it without a filter shouldn’t be a big issue in a short time for most models. Sometimes, people just forget to purchase filter replacements, and they want to use the humidifier immediately.

But you still need to get the replacement as soon as possible, avoiding any malfunction that will happen with time. 

What does a humidifier filter do?

What does a humidifier filter do

The humidifier is a godsend for many of us; however, it is also notorious for upkeep. The water in the water tank is humid and standing, which is a perfect place for the growth of germs.

The dissolved mineral will also settle down in the tank, becoming mineral deposits that can clog the machine.

This is what a humidifier filter comes into play. It can filter out the mold, bacteria, and mineral buildup so that these impurities will not get into the air along with water vapor. Don’t underestimate the effect of these substances. They will pose health risks to you when inhaled and shorten the lifespan of the appliance.

Cleaning the filter frequently is required. As more and more harmful bacteria and dirt get into the filter, it will become clogged, and it’s time to replace it.

What to consider when using a humidifier without a filter?

Until now, you already have a firm understanding of the importance of a water filter. When your humidifier has to run without a filter, you need to take some measures to diminish the adverse effects the filter tries to prevent.

Types of water 

When you use a humidifier without a filter, you should only use distilled water or at least purified water. (Check here to know the difference between distilled water and purified water.)

Since distilled water doesn’t have any or only has minimal dissolved minerals, the mineral buildup is hard to form in the tank. Accordingly, no white dust will be expelled into the air. 

Aside from that, there would be much fewer germs in the machine and you will not be too concerned about the air quality even without the protection of a filter.

Frequency of cleaning 

Even if you fill the water tank with distilled water, you still need to increase the cleaning frequency compared to using humidifiers with filters.

The mold spores and dirt in the air will land on the water in the tank. When the water is stagnant, those microorganisms will start to survive and thrive. There is no filter to help you clean them off, and you need to remove them more regularly. 

Humidity control

Many filtered models use a fan to blow out the vapor, and the filter can decrease the speed of evaporation to some extent.

When there is no filter to impede the evaporation, more moisture particles may enter the air. Hence, you may need to change the settings to prevent the room from becoming over humidified. 

While dry air will lead to many discomforts, damp air will also cause dust mites, molds, and other consequences. 

How to operate a humidifier without a filter?

Rather than continuing to use a clogged filter that may promote the growth of germs, you can choose to use a humidifier without a filter temporarily. 

To achieve it, you can follow these simple steps below.

Step 1: Unplug the device. Humidifiers are electronics, so you should unplug them before taking any action to avoid electric shock. 

Step 2: Remove the old filter. The location of the filter varies according to models, but it is easy to figure out. Once you find it, take it out to check its state. Sometimes you can try to clean it instead of throwing it away.

Step 3: Dump the existing water and then fill the water with distilled water. It is vital to remove the stagnant water in the tank because it is the breeding ground for germs. Water quality becomes more crucial since there is no functional filter, and distilled water is your best bet.

If you find the water tank is dirty, you can clean and sanitize it with white vinegar.

Step 4: Put everything back and turn it on. You should check whether the machine can continue to work. If you see any leaks or overheating, please stop using it immediately.


When using ultrasonic humidifiers and steam vaporizers, running them without a filter is a normal operation.

But furnace humidifiers and evaporative humidifiers often work with a filter that has to be replaced every two to three months. When you don’t have any replacements at hand, you can try to run your humidifier without a filter for a short period. It would not be problematic in most cases. 

However, you should only use distilled water and clean the machine more regularly since there is no filter to remove germs and dust. Don’t forget to get the replacement as soon as possible, as your humidifier is designed to work with it.

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Liz Yang is the founder of Airsmartly. She has been working at home for a few years and realizes that the performance of the HVAC system plays such an important role in our life. She has tested more than 150 products in person, including humidifiers, air purifiers, dehumidifiers, and ACs, and wants to share tips about using or troubleshooting these products with you. Her uncle is an HVAC expert with over 30 years of experience in the field, and often offers assistance when she is unsure how to handle a situation. He is also in charge of reviewing the articles on this site.

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