How Often To Change Humidifier Filter (For Max Performance)

A friend once asked me why her humidifier smelled awful. I asked her when was the last time she changed the filter, and she just stared at me.

She had never done it!

Replacing your humidifier’s filter is crucial for both your and your unit’s health. But how often should you change a humidifier filter?

My guide will tell you when to get a new filter for your type of humidifier. I will also cover the most popular humidifier brands and their special considerations.

When Should I Change My Humidifier Filter?

How often you must change your humidifier filter depends on the type of humidifier you use. Here are my guidelines for the most common humidifier types.

For Central/Whole House Humidifiers

Most manufacturers recommend replacing a whole-house humidifier filter once a year, at the beginning of winter/heating season. Whole-home humidifiers have large filters and are designed to be used daily, so they don’t require much maintenance.

If you suffer from asthma (like I do), allergies, or other breathing problems, I recommend changing a whole-house humidifier’s filter every three months.

For Portable Humidifiers

The filter of a portable humidifier — whether cool mist or warm mist unit — should be replaced every 1-4 months. The filter change frequency depends on the type of humidifier and its brand.

I’ll cover the most popular humidifier brands below, so keep reading!

The best way to know when to change a portable humidifier’s filter is to keep an eye out for these telltale signs of dirty filters:

  • Sputtering or spitting noises
  • Water ejecting from the nozzle
  • Little or no water vapor or steam
  • Foul smell
  • Dirty water in the humidifier’s water tank

For Ultrasonic Humidifiers

Most ultrasonic humidifiers are unfiltered, so there’s no need for filter replacement. They are convenient devices that require less maintenance, which is why I love them.

As a downside, they could spread white mineral dust into your home, so only use distilled water in them. If you have a unique filtered ultrasonic unit, replace the filter every 1-4 months.

For Furnace Humidifiers

A furnace humidifier filter (also called an evaporator pad) should be replaced annually at the beginning of the winter months, like with any other whole-house humidifier. However, these units are built-in humidifiers connected to your HVAC system and can be challenging to take apart. I would hire an HVAC technician to replace the filter on a furnace humidifier.

For Evaporative Humidifiers

The wick filter of an evaporative humidifier should be replaced at least every three months. The filters may get dirty much faster if you have hard water or live in a dusty region (or both — I live in a desert) so check the filter regularly.

Humidifier for Good Sleep

Can I change a humidifier filter myself?

You can change most humidifier filters yourself. The manufacturer’s instructions should detail the whole process.

You can order new humidifier filters directly from the manufacturer. I also like checking sites like Amazon for cheaper alternatives.

If you have a furnace humidifier, though, I advise getting a professional to change the filter. These filters can be difficult to access and an HVAC professional has all the tools to make the job easy and quick. I also usually ask them to give the furnace humidifier a basic maintenance inspection at the same time.

Popular Humidifier Brands and Changing Their Filters

I’ve used a lot of different humidifiers and they need filter replacement at different times. You should always check the owner’s manual to see when and how to change the filter, but here are my experiences with various brands.


I recommend changing a Honeywell humidifier filter every 30-60 days. Honeywell notes that its filters are sensitive to hard water, so check the filter regularly and use distilled water instead of tap water.


Aircare humidifiers require you to change the filter wick every 30-90 days to effectively maintain indoor air quality. Aircare also recommends that you monitor the water quality and mineral buildup in the wick.


With Bionaire humidifiers, I recommend you replace the filter every 2-4 months. There’s some variability between different Bionaire devices, so the company includes an instructional filter change sticker on the machine to let you know the ideal filter change frequency.


Aprilaire recommends replacing the filter (called a water panel) once a year. However, these whole-house humidifiers have a convenient digital warning system that lets you know if you need to replace the filter earlier.


Vicks humidifiers should get a filter replacement every 30-60 days, depending on water quality and use. Some Vicks units are filterless and will never need new filters, but you should clean these devices every few days to keep them free of mold, bacteria, and mineral deposits.

Why Do Humidifiers Need Filters?

A humidifier filter carries out several vital tasks, including:

Trapping Particles: Humidifier filters can catch pollen, dust, and other particles. While they won’t clean the air, they can reduce the amounts of air pollutants as they add moisture to your home (which is great for my asthma).

Mineral Absorption: The filter traps minerals dissolved in water. Filterless humidifiers, like ultrasonic devices, may spread those minerals throughout your home as white dust, which can irritate both your airway and nerves.

Wicking: In an evaporative humidifier, the filter doubles as a wick, absorbing water from the reservoir. A fan blows air over the wick, evaporating the water to increase humidity levels.

White Humidifier on Top of Bedside Table with Books

How To Change a Humidifier Filter

Now, I can’t tell you how to change a humidifier filter on every device. In general, though, you can follow these basic steps to change the filter:

  1. Make sure that you have a new filter ready. You can buy cheap new filters on Amazon.
  2. Turn off your humidifier before changing the filter.
  3. Remove the front or top cover of your humidifier. Most units have a “pop-off” cover, but you may need to remove some screws.
  4. Take the filter out and check that the water tube is positioned correctly.
  5. Clean the inside of the unit, including the filter tray.
  6. Place the clean filter in the unit along with the filter housing.
  7. Replace the cover and fill the water reservoir.
  8. Dispose of the old filter according to manufacturer’s instructions.

Your device may require additional steps, so I recommend checking the owner’s manual for detailed instructions.

Brown Humidifier with Wood Design

People Also Ask (FAQ)

What happens if you don’t change the humidifier filter?

If you do not change your humidifier filter, it will eventually get clogged with dust and dirt. This can result in mold growth, and a dirty filter will hinder airflow through the humidifier, which could break it over time.

Can you clean humidifier filters?

You may be able to clean some humidifier filters, but they are typically designed to be completely replaced. You likely can’t completely remove all debris from the filter, and a damp filter could see mold and bacterial growth. Some cleaning solutions will also damage filters.

How can I make my humidifier filter last longer?

The best way to make your filter last longer is to regularly clean both your humidifier and your home. Vacuuming floors and dusting surfaces extend the filter’s lifespan by reducing the amount of debris that can get trapped in it.

Can a dirty humidifier make you sick?

Yes, a dirty humidifier can make you sick because it may spread bacteria, mold, and mildew to your home through the water droplets it produces. (1)

Why does my humidifier filter turn brown?

A humidifier filter turning brown or orange indicates that you have hard water in your home. It shows your filter is working — it turns brown when it absorbs minerals from tap water. I recommend using distilled water to reduce mineral buildup.


Changing the humidifier filter is a critical part of maintaining the unit. In general, I recommend changing the filter every three months.

However, you may need to change the filter more or less often, depending on your brand, model, and water quality. Check the manufacturer’s instructions to make sure you change the filter on time and can enjoy healthy humidified air.



Josh Mitchell

Josh Mitchell

My name is Josh and I am obsessed with DIY and improving my family home. HVAC topics can be tricky for homeowners so I decided to share my knowledge on the subject. When I am not working on DIY projects, you can find me at the beach or my local coffee shop.