How to Buy a Whole House Humidifier | FurnaceCompare®

Along with a chill, winter brings dry air, which your furnace circulates throughout your home. If your house feels too cold during winter adding a retrofit humidifier can help make your home more comfortable. Plus, whole-house humidifiers help extend the life of wood floors, musical instruments and artwork.

Lack of moisture in the air can make you feel colder, which can cause you to turn up the heat and increase your energy bill. The Environmental Protection Agency recommends keeping indoor humidity under 60 percent, with an ideal humidity of 30 to 50 percent. Higher humidity levels can lead to mold, while lower levels can cause discomfort, along with nosebleeds and infections.

Before installing a whole-house humidifier, you should consider your unique situation. This guide explains the differences between evaporative and steam humidifiers, how each type of system works and how to select a humidifier that’s right for your home.

Types of humidifiers

If you only notice dryness at night, in certain rooms or for one or two months out of the year, installing a room humidifier might improve the comfort of your home. These units disperse warm or cool vapor through either an evaporative or ultrasonic process. Evaporative humidifiers are typically more affordable but require regular filter replacements.

If your home feels dry during several months out of the year and the lack of moisture impacts your health and comfort, you should consider a whole-house humidifier. These systems utilize the air heated by your furnace to disperse humidity through your entire home.

There are two types of furnace humidifiers: evaporative and steam.

Evaporative humidifiers

Evaporative whole-house humidifiers pass warm air through an evaporator pad, which is a ceramic-coated pad saturated with water. The hot air absorbs the moisture and moves it through your home. Evaporative humidifiers receive power from your furnace’s fan and are installed in your ductwork. These bypass units are installed on the cold-air return, and warm air from the furnace supplies the humidifier. During summer, when your air conditioner is running, a damper in the bypass vent pipe closes off airflow through the furnace humidifier.

Steam humidifiers

A steam whole-house humidifier heats water in a canister and converts the water to steam, which the unit forces through your ductwork. Although these systems are installed in your ducts, many do not need to connect to your furnace. These fan-powered models install directly on the warm-air plenum. They can also install on the cold-air plenum if connected to a source of hot water. The built-in fan pushes the moisture into the outgoing flow of warm air and distributes moisture through the furnace humidifier.

Capacity and compatibility

When choosing a humidifier, select a model that can provide enough moisture for your entire home. Approximately 12 gallons of water per day can humidify an area of up to 3,000 square feet. Humidification calculators can provide a more specific estimate.

Many manufacturers offer humidifiers that are compatible with your specific furnace. Installation of a universal humidifier typically does not void a furnace’s warranty. However, you should review all warranty information or consult with an installation technician before installing a humidifier.

Resources are available at to help you find a top-rated HVAC technician in your area. Consulting a professional can help you choose the right humidifier for your home.

Installation and maintenance

Some humidifiers are reversible, meaning they can be installed on the warm-air plenum or the cold-air duct. Many humidifiers must be connected to a drain. Carefully read any supplied instructions before installing a whole-house humidifier yourself. Some warranties require the whole-house humidifier to be installed by a licensed HVAC technician.

Humidifiers require routine maintenance to avoid becoming a breeding ground for biological contaminants. For evaporative units, HVAC technicians advise replacing the humidifier pad annually, as prolonged use may reduce the pad’s ability to absorb water. If you have a steam humidifier, you should flush sediment from the tank annually. Consult your owner’s manual to determine the ideal maintenance schedule for your system.

Whole House Humidifiers In Your Area

For assistance with the selection, installation and maintenance of a whole-house humidifier, contact a pro below to find a reputable HVAC professional in your area.

Find a Certified Heating & Cooling Professional In Your Area

Contact a top-rated local expert to help with all of your home's HVAC needs.

Ready to get a quote from an HVAC contractor?

Let us know what type of service you need and we can connect you with a certified local HVAC contractor.

Please enter a valid name

Please enter a valid phone number

Please enter a valid zip code

There are no dealers in this zip code.

Please enter a valid email address

Please select repair or replace

Please select heating, cooling or both