“In-duct humidification”, “in duct humidification” and “duct humidification” are interchangeable terms used to describe humidification systems integrated into the ductwork of HVAC installations. All refer to the process of introducing moisture into the airstream within the ducts prior to air distribution throughout the building. The term “in-duct” specifically denotes the placement of the humidifier inside the duct system, whereas “duct humidification” broadly refers to the humidification occurring within the duct infrastructure.