During winter, low temperature is not the only reason why your home feels uncomfortable. It is low humidity levels that dry out your skin and make you feel uncomfortable. A whole-house humidifier can solve the problem by raising the humidity levels in your entire house. But how does a whole house humidifier work? We are going to explain that in this post.

What Is a Whole House Humidifier?

A whole-house humidifier is attached to the heating system to add moisture to the air. The device brings water vapour into the ducts and disperses humidity with the help of a distribution tray. Read more about mechanical ventilation.

There are a host of benefits of using a whole-house humidifier. By raising the humidity in the air inside your home, a humidifier can prevent the growth and spread of viruses. As a result, your family members become less susceptible to flu-like symptoms and other respiratory conditions.

A whole-house humidifier is different from a portable humidifier. The latter is a device that is plugged into a wall and used in a single room. Moreover, a portable humidifier won’t humidify multiple rooms at a time.

How Does a Whole House Humidifier Work?

There are three main types of whole house humidifiers. We encourage you to learn how they work.  

Steam humidifiers

A steam humidifier senses the humidity in the home with a humidistat. The humidistat does not measure the temperature like a thermostat; it measures the moisture in your home. When the humidity drops below a certain point, the steam humidifier pumps moisture into the house. 

The steam humidifier is part of the heating system. It boils water in a reservoir, creating steam. The furnace works in tandem with the steam humidifier by slowly dispersing the moisture throughout the house through the ventilation system.  

A steam humidifier is more energy-efficient than other humidifiers.

Drum Humidifiers

Drum humidifiers, aka reservoir humidifiers, harness the power of evaporation. Air that moves through the ductwork flows into a unique bypass tube containing the humidifier, which moisturizes the air.

Drum humidifiers are efficient but not very environmentally friendly. Under certain conditions, bacteria can form in the standing water.

Flow-through humidifiers

Similar to the drum humidifier, a flow-through humidifier uses the principle of evaporation to create moisture. Both use a unique bypass tube to redirect warm air from the heat duct to the humidifier. And both use absorbent pads to hold water, which migrates into the air moving through the humidifier. But the difference is that a flow-through humidifier does not have any moving part. The unit has a pad that receives hot air from the HVAC system, and then the duct system carries the moisture into your home.

The main difference between a drum humidifier and a flow-through one is the water source. Instead of using a water drum, a consistent stream of water sprays across the humidifier pad. The water spray significantly reduces the risk of bacterial contamination.

Humidifier Installation, Operation, and Maintenance


You can install a humidifier at any time. For this, you do not have to wait to install a new furnace or new ductwork. Make sure there is enough room for the humidifier after installing the air handler or furnace. The closet should not be too tight.

Also, make sure there is a source of water nearby. Do not install the humidifier in an unconditioned space. Otherwise, the unit may freeze in the winter.


Without knowledge of humidifiers, you may wonder how a whole-house humidifier works? The good news is, you can use it without knowing exactly how it works. But some technical knowledge is helpful for a user. 

Your humidifier does not have to be on year-round. It is a good idea to set the humidifier to come on when the system is heating. When there is enough humidity in your home, you can close your humidifier manually.

Depending on the thermostat, you may or may not control the level of humidity from your thermostat. Most thermostats come with this feature. Otherwise, you have to use the control panel, which is usually on the ductwork.

When you set a specific humidity level, the unit will work to reach that level. There are some models with outdoor sensors. These models naturally adjust the humidity level with outdoor temperature. In such cases, high humidity does not cause window condensation.

The energy consumption of a whole-house humidifier depends on the particular unit. In general, the utility costs do not go up abruptly. Steam humidifiers are the least energy-efficient of the three types. But yet, there is a minimal electrical burden. You will not see an abrupt rise in your electrical bills.


Whole-house humidifiers do not require much maintenance. If your unit uses a humidifier filter or pad, you will have to replace it yearly. For a steam humidifier, upkeep is even easier. Cleaning the humidifier once per year is enough.

Even homeowners who have been using humidifiers for years still ask how a whole-house humidifier works? If you are one of them, consider hiring an experienced HVAC contractor for annual routine maintenance. 

How Does a Whole House Humidifier Work – Final Thoughts

For optimal comfort and wellness, controlling the moisture level in your home is as essential as controlling temperature. Using a whole-house humidifier is the best way to ensure the proper moisture level during winter.

Whichever type of humidifier you choose to use, they are a great way of achieving optimal humidity levels in your home. Moisture is essential for those family members suffering from asthma or allergies.

For many users, understanding the unit’s mechanism is essential, partly because this knowledge can help users take care of their humidifiers. We hope now you have a good idea of how a whole-house humidifier works.