If you’re looking to relieve discomfort caused by dry indoor air, a result of heating your home during the winter, or simply want to improve indoor comfort, a furnace humidifier is a great option. These simple machines help increase indoor humidity levels by adding moisture to your dry air and distributing it throughout your home via your furnace or HVAC system.
While they are most often used in the winter, whole-house humidifiers can be used year-round to consistently relieve respiratory symptoms due to allergies and asthma. Take a look at our article about relative humidity for more information.
For quick access to the sections in this buying guide, use the links below:
- What is a Whole-House Humidifier?
- Types of Whole-House Humidifiers
- How Effective are Whole-House Humidifiers?
- Installing a Whole-House Humidifier
- How Much Do Whole-House Humidifiers Cost?
- Cleaning and Maintaining a Whole-House Humidifier
What is a Whole-House Humidifier?
Also known as a furnace or ducted humidifier, whole-house humidifiers are installed directly onto your home's heating and cooling system to humidify indoor air. These models are powerful enough to cover a large area and are ideal for long-term relief and improved indoor air quality.
Allowing for less maintenance and ease of use, these whole-house humidifiers are well worth the investment for long-term relief and improved indoor air.
For a look at a wider range of all humidifier types, see our Humidifier Buying Guide.
Types of Whole-House Humidifiers
There are three main types of ducted humidifiers. While all connect to your home’s water supply and distribute moist air throughout your home via ducting, the method for moisture distribution is the key difference between them. The installation difficulty and the maintenance required also vary, so selecting the best type for your needs is essential.
Bypass humidifiers have a water pan to moisten an evaporator pad constantly. Air flows through the duct, then into the evaporator pad to grab the water, and finally distributes into your home with that added moisture. They are installed on the vertical or horizontal warm air supply or the cold air return plenum of the furnace. Most can be controlled by an external humidistat set to a desired relative humidity level, which will initiate operation as needed. Maintenance includes regular cleaning of the water pan and replacing the evaporator pad as needed.
Like a bypass humidifier, fan-powered humidifiers constantly moisturize an evaporator pad through a direct water line connection. Adding a fan inside this humidifier, however, makes for a more effective method of distributing humidified air throughout your home, as the fan pushes air through the ductwork faster. They are installed on the vertical or horizontal warm air supply or the cold air return plenum of the furnace.
Heating elements inside the steam canister of a steam humidifier use an electric current to boil the water and generate steam, operating independently of your furnace or HVAC system. The steam flows into the air through your home’s ducting to add humidity directly into the indoor air – since water is boiled before distribution, you enjoy humidified air guaranteed to be germ-free. These humidifiers use a humidistat to regulate the operation and are easy to maintain. Placement and installation can be flexible with free-standing units, including overflow protection and low-water cutoff.
How Effective are Whole-House Humidifiers?
Whole-house humidifiers are among the most effective ways to add moisture to your air. Because it’s directly connected to your water line and the HVAC system, it is the first stop for air as it travels through the ductwork before dispersing into your home. No matter what humidifier you install, a ducted unit consistently maintains comfortable humidity.
Installing a Whole-House Humidifier
Firstly, check whether your manufacturer’s warranty will be voided if you install the humidifier yourself. Some do require the unit to be installed by a licensed HVAC technician.
Bypass and fan-powered humidifiers utilize similar installation setups. They are installed on the bypass duct so the humidifier can use your home’s supply plenum to draw in air and your return air duct to disperse moisture. Most models can be mounted on the plenum or the return air drop, and some can be reversed if the supply line is inconveniently located as originally placed.
Almost all manufacturers require steam humidifiers to be installed by a qualified licensed technician due to their flexible placement options and electrical requirements.
How Much Do Whole-House Humidifiers Cost?
The good news is that you can add a ducted humidifier to your home without breaking the bank. Bypass humidifiers are the least expensive, ranging from about $140 to around $240. Replacement parts are readily available for low cost, should you need them. Replacement pads run about $15.
Fan-powered units are slightly more expensive, running from $150 to $370, depending on the size you need for your home. The cost of replacement pads or parts is very affordable at $16 to $20.
Steam humidifiers can cost significantly more than other whole-home humidifiers; prices can range from the mid $400s to over $1200. However, the heating cost savings gained from installing a steam unit can help to mitigate the initial installation cost over time. The steam canister replacements cost about $100.
Check out our Best HVAC/Ducted Humidifiers for 2023.
Cleaning and Maintaining a Whole-House Humidifier
Bypass units require the most routine maintenance, including regularly cleaning the water pan or reservoir. The evaporator pad and other parts may sometimes need to be replaced.
Fan-powered humidifiers also need the pad checked and replaced as necessary.
Steam humidifiers require the least amount of routine maintenance. Annual inspections for loose electrode and plumbing connections, drain line blockage, and steam hose alignment are all needed. This can be performed while your furnace or HVAC system is inspected.
In Summary
Installing a furnace humidifier can add comforting moisture to your entire home. Working directly on your existing HVAC or furnace system, these machines use your home’s water supply via a supply line and either an evaporator pad or steam to maintain a healthy humidity level. Select a bypass, fan-powered, or steam type to suit your installation requirements and budget.
Additional Questions
Choosing the best HVAC/ducted humidifier isn’t an easy decision. To learn more about humidifiers, take a moment to view our Humidifier Knowledge Center. Still have questions or concerns? We can help; call us at 1-800-934-9194.
