How Often Should You Change the Filter in a Humidifier?

Also like an air conditioner, a humidifier contains a filter that stops dust, mold and mineral deposit debris from being emitted by the machine.

Filter Replacement

Replace your humidifier’s filter(s) once every three months. If you use your humidifier every day, replace the filter every two months. The filters are treated with a coating that slows mold growth but doesn’t repel mold. Failure to replace your humidifier’s filter can lead to excessive dust and debris being expelled into the air as well as mold growing on the filter surfaces and on the inside of the device.

If your humidifier contains a mineral absorption pad, replace it every two to three weeks to keep mineral deposits from being emitted.

Hard Water Issue

If you live in an area that contains hard water, replace your humidifier’s filter every month, due to the high content of mineral salts present in the water. Mineral deposits clog filters faster and produce a large amount of white dust if you don’t change the filter more often.

Buying Replacement Filters

Locate your humidifier’s name and model number (usually on the back of the device) before attempting to purchase filters. Also, consider purchasing more than one replacement filter. Replacement filters are available at hardware, home improvement and retail superstores as well as directly from your humidifier’s manufacturer.

Shutting Down and Disconnecting

When shutting down your humidifier for a period of time or disconnecting it, remove its filter and replace it with a new one, and empty the device’s water tank. Then clean the humidifier according to the recommendations in your device's manual before storing it in a closet or other location. Do not leave an old filter or water in the humidifier -- mold can grow on the filter, and the water can become stale and smell.