Whole home or in-duct humidifiers are installed alongside your forced-air furnace, plumbed into your water supply, and are ideal if you want to humidify your whole house. Their easy change filters require service once or twice per year and are less expensive to run (around $30 per year, compared to as much as $350 per year for tabletop models).
There are four types of whole house units:
- Drum Style Humidifiers—Not recommended. With this type of humidifier, the motor spins a drum with a foam pad on it. The pad passes through the pan of water and absorbs some of the water. The warm air from the furnace outlet passes through the foam pad and picks up moisture through evaporation. The air then enters the furnace return duct and passes through the furnace and into the supply ducts where it is distributed throughout the home.These require more maintenance than the flow through type to keep them working properly. The maintenance includes cleaning the water pan and replacing the pad. Also, if the system is not properly shut down in the summer, the standing water in the pan can allow biological growth.
- Bypass Humidifiers—Typically the most affordable option. This type of humidifier cycles the water solenoid valve open for a few seconds and closed for a few seconds, which uses less water than other available options.
- Power Humidifiers—This type of humidifier uses its own fan instead of utilizing the furnace fan. Unit does not require the furnace to be operating in order for it to run
- Steam Humidifiers—A built-in heater heats the water until steam is produced. The steam is then passed through a nozzle and into the duct system. Typically, this has a higher capacity for situations where the furnace is not operating frequently.
Many units utilize manual humidity control (humidistat), requiring manual adjustment to match outdoor conditions. Higher end units will utilize an automatic humidity control that combines an indoor humidistat with an outdoor temperature sensor to automatically adjust the set point to the recommended level for the indoor temperature.
Our qualified service technicians and installers can recommend the proper sized humidifier for your home. There are several different size units, which are rated in gallons per day (gpd). This is the maximum amount the unit will put into the air in one day. This will vary depending on how your furnace is operating and the temperature of the air leaving the furnace.