The Aprilaire 1140 humidifier is designed for installation with its own forced air heat source and is installed independent of the building heating system. A transition fitting connects the unit to the heat source and humidified air can be discharged into the immediate area or duct work can be installed for distribution to other locations. The heating system and blower system are NOT included with this humidifier. Parts for the Aprilaire 1140 humidifier are listed here. This model is rated at 27 pounds per hour.