Whole House Humidifier Problems – 4 You Need To Know Now

The wrong setting on a whole house humidifier can cause mold growth and lead to wood damage and moisture stains. The problems with the actual unit can be avoided by the homeowners who clean the humidifier regularly and use a water softening system.

Below you will find detailed instructions on how to fix any humidifier-related issues. 

Whole House Humidifier Problems

Whole house humidifiers can be amazing at helping you keep the humidity level in your home just right. But if you are not able to adjust the settings according to the outside temperature, the system might end up causing a few problems.

Dangers of a Whole House Humidifier

  • High humidity can cause mold growth
Mold is just one of several whole house humidifier problems

If the settings are wrong, moisture from your whole house humidifier can end up accumulating in the ducts. This, in its turn, leads to the formation of mold that then gets spread all over your home.

Mold spores can affect your health and the worst thing is that this substance is not always visible (it might grow inside the walls).

Tip: keep the humidity level between 30% and 50% to avoid mold growth.

Read: Mold In Air Ducts Symptoms

  • High humidity can damage wood

Moisture can cause the roof to rot, as well as damage wooden floors and furniture.

Unlike a portable humidifier that focuses on one space, whole house humidifiers affect the humidity level in all of the areas, which means that too much condensation can form even in the attic.

  • High humidity leads to moisture stains
moisture stains caused by humidity

This is not something that is going to affect your health or ruin the structure of your house, but moisture stains can be extremely annoying.

The moisture that condenses on the windows can create stains that are challenging to get rid of. These little nuisances can ruin the aesthetics of your house.

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Read: Signs Of High Humidity In Your Home

  • A whole house humidifier might be hiding HVAC air leaks

The air in your house may have gotten so dry in the first place simply because your HVAC system has plenty of gaps and cracks.

It is extremely important to seal your house and double-check the ducts for air leakage before installing a whole house humidifier

Read: Honeywell Humidifier Damper Position On Winter/Summer

Why Is My Whole House Humidifier Not Working?

The other type of whole house humidifier problems that you might encounter include issues with the actual system itself.

The Humidifier Isn’t Getting Any Water

Of course, if the system isn’t getting any water, it won’t be able to humidify.

Here are a few reasons that might be to blame in such a situation:

  • The solenoid valve isn’t opening
humidifier solenoid valve

The solenoid valve looks like a sprinkler valve. It’s an incredibly important element that is connected to the humidistat and to the furnace transformer.

If there is something wrong with the solenoid valve, the commands coming from the humidistat won’t be ‘heard’ by the humidifier.

Make sure that there is water coming from the gate valve (water should spurt out if you loosen the pipe on the supply side of the solenoid valve). 

If everything is okay with the gate valve, then you can proceed to test the solenoid valve. Simply set the humidistat to a high humidity level and listen (you should hear a ‘click’). 

If nothing happens then you or an HVAC expert would have to test the valve with a multimeter and replace the component, if it’s defective.

  • The shutoff valve is closed

You should be able to find the main shutoff valve in the place where the supply line connects to the main water line.

If your system has a ball valve, ensure that the handle and the pipe are parallel.

If there’s a gate valve, then turn it counterclockwise as much as you can.

A saddle valve is a type of valve that’s always open. If the humidifier isn’t getting any water, then it looks like there is an obstruction inside the valve, so you might have to take it out and clean it.

  • The float valve is stuck

Inside the housing, you’ll find a tray with a float valve that is there to stop the water once the tray is full.

You can try moving this valve up and down manually. To go the extra mile, you can also spray a bit of lubricant over it.

  • There is a mineral buildup in the system

If none of the tips mentioned above have helped, then it looks like there is a mineral buildup somewhere in the supply line. You would have to disassemble the thing and clean it.

Tip: if you don’t want to deal with mineral buildup ever again, then you can consider getting a water softening system. 

Read: Why Do Humidifiers Need Distilled Water?

The Unit Isn’t Humidifying

Improper airflow is often one of the key whole house humidifier problems. Replace or clean the dirty filters and if your system has a damper, make sure that it’s always open when the humidifier is working (otherwise, the damper might be depriving the system of air).

If your whole house humidifier has an evaporator pad, then a mineral buildup on the pad might be causing the problem. You can try soaking the thing in vinegar, but if it doesn’t help, simply replace the pad.

whole house humidifier

If you have a drum-style humidifier and you hear humming or knocking sounds coming from the system, then there might be an issue with the motor or the drum. These parts may need replacement.

If a steam generator is not humidifying, then it might be because the system is not heating up. Check the power supply, reset the circuit breaker, and replace a blown fuse, if there is such a need.

Read: How To Increase Airflow In Ductwork

There Are Musty Odors Coming from the Humidifier

Unfortunately, different kinds of bacteria and mold love humidifiers as they increase the moisture level in the system and the house.

All these microorganisms can grow not only in the rooms but also in the water trays and drainage trays.

Drum-style humidifiers recycle the water from the tray (they don’t drain it) and that’s exactly why such systems are especially vulnerable to mold growth.

However, steam generators can suffer from such a problem as well. Such units circulate the steam through the ducts, and if there are any cold spots within the system, the steam is going to condensate on the walls.

If there is a musty odor coming from your whole house humidifier, then there is mold growing in the system and the best thing that you can do is plan duct disinfection and cleaning.

You can prevent these types of problems by regularly cleaning the trays, the evaporator pad, and the drum.

Flush the components with water or a bleach solution and let them dry before placing the components back into the system. Done regularly, this alone can take care of several of the most common whole house humidifier problems.

Do Whole House Humidifiers Need to Be Cleaned?

It is essential to maintain your humidifier if you want to avoid all of the problems mentioned above.

Here are some easy-to-follow instructions:

  1. Turn the power off, unplug the humidifier, and disassemble it.
  2. Empty the water reservoir and then fill it with a bleach solution. Swirl the water around and get rid of any buildup.
  3. Replace the water panel (water and evaporator pad and filter) at least once a year.
  4. Clean the outer body of the humidifier with a cloth dipped in diluted vinegar.

Tip: don’t leave any water in the humidifier, if you do not intend to use it. For example, if you are going on holiday in winter, drain the humidifier completely before you leave.

Read: Why does my humidifier leave white dust?

How Long Does a Whole House Humidifier Last?

Of course, the lifespan of your unit is going to depend on how well you were able to take care of it and the quality of water.

The life expectancy of a whole house humidifier is between 10 and 15 years.

These signs might mean that it’s time to replace your unit:

  • You have had the humidifier for over 10 yearsAt this point, it may be much cheaper and more beneficial to replace the unit with a new one, than to carry on using and maintaining the old humidifier.Moreover, as the unit ages, the water tank tends to develop cracks and leaks.
  • Your house’s parameters have changedIf your house has been reconstructed or had undergone a wide range of changes, the humidifier might not be able to meet the workload required any longer.
  • You’ve done a bad job at maintaining the unitIf you haven’t changed the pads and never cleaned the humidifier, then it might be more cost-effective to replace the whole unit. Disassembling the system, cleaning every single part, and replacing the elements that have gone bad may cost you a small fortune.

Read: Whole House Furnace Humidifier: Everything You Need To Know


Now that we’ve covered some of the most common whole house humidifier problems, you are better equipped to figure out which one (or ones) are affecting your system.

Remember: Regular maintenance will go a long way towards keeping your humidifier working for you, rather than against you.