How Often Should You Change a Humidifier Filter?

How often to change humidifier filters

Dmitry Marchenko / EyeEm / Getty Images

Humidifiers soften the air and help you feel more comfortable during the driest season of all: heating season. Yet a humidifier is only as effective as its filter. A clogged humidifier filter cannot efficiently deliver air. With wick evaporative filters, the filter's ability to draw water from the tray is hampered with a filter clogged with minerals or impurities. Find out how often to change a humidifier filter for better air quality and a more effective humidifier.

How Often to Change a Humidifier Filter

The type of humidifier you own—whether a large or small portable humidifier or a furnace humidifier—affects how often you should change the filter.

  • Large portable humidifiers: Change the wick filter on evaporate humidifiers four times per year.
  • Small portable humidifiers: While there is no need to change a filter, ceramic filters need to be rinsed every 30 cycles.
  • Furnace humidifiers: Change the filter once per year at the start of the heating season.

Large Portable Humidifiers

Large portable humidifiers between approximately 500 and 4,000 square foot capacity are usually evaporative humidifiers. An evaporative humidifier draws water by capillary action from a water tank to permeate one or two paper wick filters. A fan blows air through the wick filter to humidify the air.

Humidifier wick filters should be changed about four times per year or sooner, if dirty.

Small Portable Humidifiers

Many small or tabletop humidifiers under around 500 square foot capacity have no filters. Some humidifiers do have aromatherapy pads, which resemble filters. Pads generally can be cleaned and reused.

Ceramic filters in the water tank should be cleaned as often as every 30 cycles or if you see that the filter is dirty. Fully submerge the filter for five minutes in white vinegar, rinse with clean water, and let it thoroughly dry. Ceramic filters rarely, if ever, need to be changed.

Furnace Humidifiers

Furnace humidifiers deliver moist air to the entire house through the air ductwork and registers (vents) in each room. Integrated into the HVAC system, the furnace humidifier blows air through a water-soaked pad, which also acts as an air filter. The humidifier pad is sometimes called an evaporator panel, water wick, or humidifier filter.

Most manufacturers of furnace humidifiers recommend that the filter be changed once per year at the start of the heating season.

When to Change the Humidifier Filter More Often

At the least, change the humidifier filter according to its regular schedule. Increase the frequency if any of these conditions are present in your house:

  • Building: Home remodeling, repair, or building inside the house may create dust that clogs the humidifier filter. Wood sawing and drywall work, in particular, create significant amounts of fine dust.
  • Smoking: Cigarette, cigar, pipe, and other types of recreational smoking rapidly clog up humidifier filters with fine particulates.
  • Fireplaces: Wood-burning fireplaces, no matter how well vented, still exhaust particulates to the indoor air. Natural gas fireplaces will not affect the humidifier's filter.
  • Animals: Cat and dog hair and dander are large impurities that quickly fill humidifier filters.
  • Water: Hard water creates mineral deposits that can clog wick filters.
  • Climate: Wildfires, smog, or other poor air quality events will affect your home's humidifier filter, as well.

Tips for Extending the Humidifier Filter's Life

  • Vacuum and sweep the floors frequently. Use a vacuum with a HEPA filter.
  • Limit construction or building activities to the exterior, whenever possible. If this is not possible, create dust barriers in the home to prevent dust from traveling.
  • Traditional wood-burning fireplaces are being phased out in many communities because they create a significant amount of air pollution. Consider converting your wood-burning fireplace to a natural gas fireplace. Ventless gas fireplaces are a good option for homes where it's not practical to vent to the outdoors.
  • Keep your pet well-groomed at an off-site pet groomer. Between visits, brush or comb your pet by yourself, but do so outdoors or away from the humidifier.
  • Use distilled water in the humidifier's water tank.
  • With climactic conditions beyond your control, turn off the humidifier when the Air Quality Index (AQI) reaches 100 (orange).
Article Sources
The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. What Is the AQI? EPA /