Common Humidifier Problems and How to Fix Them

Why is my humidifier not working? Even the best humidifier needs to be used properly and needs to be maintained on a regular basis! Always check your manufacturer’s instructions first, and understand that some repairs you perform yourself may void your warranty.

All household appliances require general maintenance from time to time to retain their usefulness and prolong their shelf life. It is much easier if your appliance is still under warranty- you only need to send it back to the manufacturer! However, if humidifier has broken down after the warranty period, what should you do?

Listed here are some common problems concerning humidifiers and repair tips to help you fix the humidifier that is not working quickly and easily.

Warning! To avoid personal injury or even death, always disconnect your appliance from its power source–that is, unplug it or break the connection at the circuit breaker or fuse box–before you do any troubleshooting or repair work on your appliance. Also, because some components may have sharp edges, use caution while working on your appliance.

It If You Notice Your Humidifier’s Leaking Water

The water supply attached to your humidifier provides the moisture that’s necessary to adequately humidify your home. The water supply may be turned on by the humidifier to fill a reservoir tank or it may continuously flow over a filter medium whenever the furnace blower is on.

If the humidifier has a reservoir, when the water collects to a certain depth in the holding tank/tray, a mechanical float ball rises to the surface of the water, shutting off the water supply. If the float mechanism sticks or is otherwise defective, the water may not shut off properly–so the tank/tray overfills and spills out onto your floor.

What you probably need to do is replace the entire float mechanism. You could be successful with cleaning it or replacing one or two components, but the cost of a new float is comparable to the cost of some of its individual components.

If your humidifier leaks water continuously while the furnace blower is running, check all hose and/or tubing connections to be sure that everything is tight. Then, open the cover and make sure the filter is in its proper place and position. Finally, make sure the water drain line/tube is unobstructed and unclogged.

It Works Fine, But The House Is Too Dry

Humidifiers have one major drawback; they humidify only when the furnace blower is on. If your house is well insulated and you have a high-efficiency furnace, the blower may not run long enough to evaporate an adequate amount of water into the air. Then you have two options:

  • Set the furnace fan to run continuously.
  • Supplement the furnace humidifier with a freestanding humidifier. 

Humidifier Making A Loud Noise

While humidifiers run, they either add water to the filter pad or reservoir, or they spin their cylindrical pad through the reservoir. The solenoid that allows water to flow into the flow-through type can be noisy, as can the motor that spins the pad in a reservoir.

There’s usually no remedy for this noise. If it’s very noticeable or bothersome, qualified heating and cooling contractor may be able to help.

Humidifier Doesn’t Run At All

If your dehumidifier does nothing at all, the humidistat may be set too low or too high. Try turning the humidistat to a setting calling for greater humidity, then turn your furnace up 5 degrees higher than the current room temperature.

When the furnace blower turns on, the humidifier should function. If it doesn’t, you may have lost power to the unit, or one of the electrical components may have failed–the valve, motor, or step-down transformer.

If these are okay, check for a problem in the water supply, or contact a qualified heating and cooling contractor to diagnose and fix the problem.

There’s No Water In The Reservoir

If there’s no water in the reservoir, first make sure that water is getting to the humidifier. The humidifier must have a good stream of water available to it. If there’s water in the waterline, but the reservoir doesn’t fill, replace the float mechanism inside the humidifier.

There’s No Water Flowing Through My Flow-through Type Filter Pad

If there’s no water flowing through the humidifier filter pad, first make sure that water is getting to the humidifier. The humidifier must have a good stream of water available to it. If there’s water in the waterline, but it’s not flowing to the pad, you may have a stuck, clogged, or defective water valve.

Often these valves can be cleaned. Try removing the water line from the inlet side of the valve and cleaning out the valve. There may be sediment clogging the orifice. If it’s clean, check the coil with an ohmmeter; it may be burned open, or the humidistat transformer may have failed. If none of these is the problem, we suggest you contact a heating and cooling technician for further assistance.

The Humidifier Pad Doesn’t Spin

A small motor on the side of the humidifier spins the rotating filter pad on the reservoir type of humidifier. If it doesn’t spin, adjust the humidistat to make sure it’s calling for more humidity. Then turn on the furnace. When the furnace blower is on, if the pad still doesn’t rotate, the motor may be defective. If so, you need to replace it.

Now you know how to perform humidifier repair. This guide covers how to fix furnace humidifiers. If you need help with other types of humidifiers, see the owner’s manual. Repairing a humidifier is easy, that’s because these machines are easy to understand.

Mas Broto

Written by: Mas Broto

Mas Broto is a small business owner with 30 years experience in the real estate industry. He is the founder and editor of, the most comprehensive free home improvement website on the planet!