How to Clean a Humidifier

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Take care of your humidifier so it can take care of you.

Keeping a humidifier running—especially during the winter months—can be a game-changing health habit. Adding a little bit of moisture into your home’s dry air can help with everything from preventing bloody noses and cracked lips to helping to keep your skin hydrated and prevent eczema. Yet, according to an informal survey conducted by Consumer Reports, 59 percent of respondents who use a humidifier said they do not clean it every day and one in four people clean theirs twice a month or less. Not shocking, considering many of us probably don’t want to commit the time to proper maintenance, but experts warn we need to provide the unit with extra TLC—and not just at the end of winter. Reader’s Digest spoke to John McKeon, MD, CEO and Founder of Allergy Standards, to learn how to clean a humidifier. If you don’t have a humidifier at all, these are the 13 best humidifiers for 2021.

Why do you need to clean your humidifier, anyway?

Dr. McKeon explains that it all has to do with how a humidifier works. “By its nature, there is water passing through a humidifier,” he says. “The water tank is usually filled by the user, and then the humidifier will disperse this water into the air in the room to increase the water content in the air.” Here is another nifty trick to humidify your home.

Any time there is stagnant water, the growth of bacteria and mold is a possible scenario. “If the water is not refreshed regularly, you risk spraying infected water into your home,” he explains. This is why it’s not only important that your humidifier has a sanitization function to neutralize any mold before it can be released into your room, but that you clean the humidifier regularly, to ensure there is no build-up of mold or other particles.

“If there are a lot of minerals in the tap-water where you live, you will also need to clean any mineral build-up from the humidifier,” he adds. If you live in an area with hard water, use distilled or boiled water in your humidifier to reduce the mineral build-up.

How often do you need to clean your humidifier?

Luckily, most humidifiers come with an instruction manual that tells you exactly how often you should clean your humidifier—and you should clean it regularly. Additionally, if you are going to put it in storage, or not use it for a few months, make sure there is no water left in the tank before putting it away and clean it before and after, he instructs. “You want to ensure that there is no reason for mold or bacteria to grown within the humidifier.” Did you know that air purifiers may also play a role in protecting your home and family from germs?

What do you need to clean your humidifier?

  • Your owner’s manual: “Different models have different recommended methods of cleaning,” says Dr. McKeon, so always check your manual first. Here’s why you shouldn’t use bleach on every part of your humidifier.
  • Small brush: A small brush, even a toothbrush, will help you clean hard to reach spots. This small brush set comes with everything you need to clean your humidifier and nearly every other odd place and gadget in your home.
  • Cleaning disinfectant: This can include bleach, vinegar, or a hydrogen peroxide solution.
  • Gloves and goggles: If you are working with any harsh chemicals, you should always protect your hands and eyes, Dr. McKeon points out.

Here’s how to clean your humidifier

In order to avoid the fear of contaminating yourself or your family from a dirty humidifier, take these steps to sanitize your device.

  1. First of all, you should read the owner’s manual. Yes, it’s annoying and very tempting to just toss the manual, but it’ll help you know the appropriate cleaning schedule to be following. Look for the manufacturer’s directions: If it is recommended to clean your model regularly, then schedule this simple task in your daily routine. Also, make yourself aware of any warnings and take effective precautions, like unplugging your machine before disassembling it.
  2. Empty the tank: Whether you are just cleaning it so that you can reuse it immediately, or plan on storing your humidifier, make sure to empty all existing fluid from the unit.
  3. Check filters: Prior to cleaning, remove any filters. You should always replace your dirty filters, but once you are done with using your appliance for the season, get rid of any humidifier filters or cartridges before sitting it on a shelf. You will want to start fresh.
  4. Clean the unit: Using a small brush and wearing gloves and goggles, clean the unit with the recommended disinfectant, making sure to remove all mineral deposits from the tank.
  5. Rinse the unit thoroughly: “If you use a weak bleach solution, vinegar, or any other chemicals as suggested by the manufacturer, make sure you rinse the tank several times after cleaning so that these chemicals are not spread into the air when you next switch on the humidifier,” he adds.
  6. Dry the unit thoroughly: After cleaning—and especially if you are planning on storing it—make sure to dry the unit thoroughly. You can do this with a towel or allow it to air dry.
  7. Refill with water: Now your unit is ready to use again. Follow instructions and refill with water.
  8. Sanitize the water: McKeon recommends selecting a humidifier with a sanitizing function. After refilling, run the sanitizing cycle. “This means that the water is sanitized in the machine before it is released into the air, using UV or other technology, which will deactivate any mold or bacteria in the water,” he explains.
  9. Repeat the process regularly: McKeon reiterates that regular cleaning of your humidifier will ensure that your air will be cleaner and free of any mold or bacteria. Here are other places bacteria and germs can hide in your home.

When should you replace a humidifier?

The good news is, if you stick to the recommended cleaning instructions, your humidifier should last a long time, Dr. McKeon promises. However, there are a few situations when you should consider investing in a new one:

  • It breaks: The obvious reason to invest in a new humidifier is if yours is broken.
  • It’s not efficient: If your unit isn’t hydrating the air properly, it is time for an upgrade. You can figure this out by investing in an inexpensive device called a hygrometer that measures the relative humidity in a room. “Ideally you want the humidity to be between 30 to 60 percent,” he points out. “It is possible for air to become too humid if you leave the humidifier running continually without monitoring humidity, and this can encourage the growth of mold and bacteria in the room, as well as shortening the life of your humidifier,” he says.
  • It isn’t the appropriate size: Size matters when it comes to a humidifier. “It is important to choose a humidifier that is appropriate for the size of the room in which you intend to use it,” Dr. McKeon says. An easy way to check if your unit is sufficient for the room it is in is to read the instruction manual.
  • It isn’t certified: It’s helpful to choose a humidifier that has been tested against some of the potential issues outlined above, Dr. McKeon points out. “The asthma & allergy friendly® certification standard for humidifiers tests that a humidifier can increase and maintain humidity in a room,” he says. “The humidifier is also run in a sealed chamber with a contaminated water source, to check that the sanitization function can remove any contamination before it reaches the breathing zone.”

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Leah Groth
Leah is a Philadelphia-based writer, editor, mother and product junkie. Her obsessions include old houses, home design, fashion, beauty, books and anything that makes her life — which includes working full-time and taking care of two "spirited" children and a Vizsla puppy — a little bit easier. Her work has appeared on a variety of publications and websites, including Glamour, Prevention, Business Insider, Livestrong, Mindbodygreen, Fatherly, Scary Mommy, Wonderwall and Cosmopolitan.