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Humidifier filters: wicks, water panels and when to replace them

By the Life in Good Form editors. Updated 2026-10-15.

We research products from makers' specs and health sources; we do not run hands-on tests. Links to Amazon may earn us a commission at no cost to you. How this works.

Which humidifiers use filters

The EPA notes that steam vaporizer and evaporative humidifiers are not expected to disperse substantial amounts of minerals, while ultrasonic and impeller units can disperse minerals and microorganisms from their tanks. See our ultrasonic humidifier guide for more on white dust.

The EPA adds that warm mist humidifiers are a type of steam vaporizer in which the steam is cooled before it leaves the machine, and that steam vaporizers should be kept out of the reach of children because steam and boiling water may cause burns.

Wick filters for portable evaporative units

Wicks are made to fit specific models. Vornado, for example, says its MD1-0034 wicks are 1 inch thick and designed for its EV100, EV200, EVDC300, EVDC500, Evap2, Evap40 and Baby Huey evaporative humidifiers. It says the wicks carry an antimicrobial treatment, need no cleaning and are disposable, and that other brands may fit but can reduce performance.

Before buying, find the model number on your humidifier or in the manual and match it to the filter listing. A wick from another brand may look similar but fit differently.

Water panels for whole-house humidifiers

Furnace-mounted humidifiers use a water panel instead of a small wick. AprilAire lists panels by humidifier series; its 700 series panel measures 10 inches high, 13 inches long and 1.75 inches wide and fits models 700, 700A and 700M. For its 620 and 720 humidifiers, AprilAire sells a HydroCore cartridge and says to replace it every 12 months. In hard water, it says to replace the orifice annually or as needed to help prevent scale buildup.

The EPA says to follow the maker's directions for cleaning and maintaining console and central (furnace-mounted) humidifiers.

Demineralization cartridges

The EPA suggests considering demineralization cartridges, cassettes or filters if they are supplied or recommended for your humidifier, but warns that their ability to remove minerals may vary widely and that more research is needed on how well and how long they work. Watch for white dust, which the EPA says would show minerals are not being removed. In areas with high mineral content in tap water, the EPA notes distilled water may cost less than cartridges.

For water choices, see our cool mist humidifier guide.

Care between filter changes

• Unplug first before emptying or cleaning, the EPA says.
• Empty and refill daily. For portable units, the EPA says to empty the tank, wipe surfaces dry and refill daily.
• Clean every third day. Scrub scale, deposits or film from the tank, then wipe dry.
• Use the maker's cleaner. Without specific instructions, the EPA suggests a 3% hydrogen peroxide solution for surfaces that touch water, then several rinses with tap water.
• Keep humidity at or below 50 percent. The EPA says higher levels may encourage biological growth; a hygrometer can help.

End of season

At the end of the humidifying season, the EPA says to clean the humidifier as directed, make sure all parts are dry, dispose of all used demineralization cartridges, cassettes or filters, and store the unit in a dry place. After storage, clean it again before use. Starting the next season with a fresh filter matched to your model keeps the schedule simple.

The EPA also says to stop using a humidifier and contact your doctor if you have breathing symptoms you believe are linked to using it, even if you follow the care directions. If your home is too humid instead, see our dehumidifier guide.

What to look for when you buy

Questions people ask

Do all humidifiers need filters?

No. Evaporative units use wicks or water panels, and some ultrasonic units use cartridges; check your manual.

How often should I change a humidifier filter?

Follow your maker's schedule; AprilAire says every 12 months for its HydroCore panel.

Can I clean and reuse a wick filter?

Vornado says its wicks need no cleaning and are disposable; follow your own maker's instructions.

Do demineralization cartridges stop white dust?

The EPA says their ability to remove minerals may vary widely; white dust means minerals are getting through.

Will another brand's filter fit?

It may, but Vornado says non-genuine wicks can reduce performance; match the model number.

Sources

• Use and Care of Home Humidifiers (epa.gov), U.S. Environmental Protection Agency
• MD1-0034 Humidifier Wick (2-Pack) (vornado.com), Vornado
• HYDROL HydroCore Water Panel Cartridge (shop.aprilaire.com), AprilAire
• H735EZ1A EZKit Water Panel Assembly (shop.aprilaire.com), AprilAire

Sources checked 2026-10-15.