How to Clean a Humidifier Filter

Mist humidifiers are wonderful inventions, adding moisture to inside air in the winter. In fact, if not for humidifiers, our furnaces and other heating devices would make the air so dry that the mucous membranes in our eyes, nose, throat, and lungs would dry up and turn into imitation leather. And this is one of the main causes of winter colds, flu, and other illnesses.

But humidifiers present their own health hazards, not least of which is the filter. This is because a humidifier filter essentially acts as a wick, bringing water up from the reservoir and exposing it to the moving air of the fan. This means that if the water in a humidifier is unchanged for days on end, bacteria, molds, and fungi breed in it and their spores are transferred to the air we breathe. Just the same as if someone with a cold had sneezed on us!

Cleaning a Humidifier Filter

  1. dirty humidifier filterWhen you clean a humidifier filter you need to remember that this filter is typically layers and layers of mesh or screen and the germs trapped in it aren’t going to come out easily or without a fight. This is true of even the smallest of them, so you need to do more than dunk the filter in a sink full of soapy water and hope for the best—no matter what other sites tell you.
  2. collection of cleaning productsThe first step in cleaning a humidifier filter is cleaning all the spaces around it. This includes the humidifier water reservoir and the base under the filter itself. The reservoir may look fine, and indeed often is, but germs are not visible. Rinse it out with a mild solution of bleach and water at a ratio of one part bleach to five parts water and then a final rinse of clear water. When refilling the reservoir, add a teaspoonful of baking soda to keep the water sweet and clean-smelling.
  3. dirty humidifier baseThe next step in cleaning a humidifier filter is to clean the base beneath the filter, which likely has a yellowish-brown scale of hard water residue that attracts and holds bacteria and germs. You can prevent this by running humidifiers with distilled water only, but this is a little expensive. To clean the scale, pour in a half-and-half mixture of white vinegar and water and let it sit for about thirty minutes. Then scrub with a brush or a 3M green pad until the scale is gone. Do not rinse. The vinegar residue will help prevent future buildup and add a pleasant tang to the air as well.
  4. bottle of scale remover with dirty filterCleaning the humidifier filter itself may involve removing hard-water scale buildup, or actual mold and mildew deposits, which show up as green or black spots. For simple mineral deposits from tap water you can use the vinegar solution above. Equally as effective is a product called CLR (calcium, lime, rust), or a generic equivalent, which attacks and removes the named buildups reportedly with no scrubbing (though I have never found this last part to be true). If the mildew is spotty, use the bleach solution above and soak for a good hour to make sure you’ve gotten it all. Another good product, but one difficult to find nowadays among the plethora of cleaning supplies, is Lysol Concentrated Disinfectant. This reddish-purple disinfecting cleaner is so strong you must wear gloves to handle it, but guarantees to remove 99.9 percent of viruses and bacteria when used as directed. I relied on it for more than a decade when my children were young.
  5. new filtersFinally, cleaning the humidifier filter may be impossible. If it is made of a certain type of plastic, or the mold and mildew is extensive, you may simply want to replace the filter. This is what some manufacturers recommend. Most smaller humidifier filters cost less than ten dollars, which isn’t much to ensure that your family is safe from some really virulent strains of mold.
  6. humidifier protecCleaning a humidifier filter may even become obsolete, given Honeywell’s continuous-cleaning humidifier cartridge. Also called the Humidifier Protec, the baby-rattle shaped device fits in most cool-mist humidifiers and promises to keep the water cleaner and fresher and slows the formation of bacteria and mold. It costs eight bucks and is advertised as safe, nontoxic, and odor-free. It may just preserve the life of your humidifier filter for an entire winter season—which isn’t bad. You can get the Pro-tec at Amazon.

Cleaning a Humidifier Filter Doesn’t Have To Be a Hassle

If you check your humidifier filter weekly and change the water when you do you won’t have a problem with bacteria and mold building up in the filter or at the bottom of the pan. Bacteria is opportunistic, as are mold spores, but it takes a while to get established and build up a network of friends and relatives. If you cut their lives short before they have a chance to network, you won’t have to clean your humidifier filter for at least a month. So put the routine on your to-do list, post it on the fridge or wherever, and designate an official mold-watcher to keep the problem under control. It will make even the smallest person feel important and keep the rest of the family from catching the creeping crud.

Humidifier Filter Cleaning Products

Bottle of CLRCLR Bathroom & Kitchen Cleaner cuts through calcium, lime, rust, and other hard-water deposits. It also eliminates soap scum, soap film, and dirt from showers, tubs, sinks, and other kitchen appliances. It’s also easier on you hands (and water supply) than many other cleaners because it contains no phosphates, ammonia, or bleach.

Bottle of Lysol ConcentrateLysol Concentrate Disinfectant removes 99.9 percent of viruses and bacteria around your home and also eliminates odors. Powerful, long-lasting cleaning that attacks crud buildup like a dynamo, this product has been around for more than half a century and is still going strong removing influenza, herpes simplex, salmonella, and staph.

humidifierfilter-9Honeywell Continuous Cleaning Humidifier Cartridge (HWLPC2) looks like a baby’s rattle but provides ongoing, continuous protection against bacteria and mold buildup in your humidifier. Designed for almost any humidifier, the device simply drops in the tank for a fresher, cleaner mist. It comes two to a package with a one-year warranty. You can get these Cartridges from Amazon.