Humidifiers add moisture to indoor air to ease breathing, make the space feel warmer, minimize static shocks, and help prevent wood surfaces and furniture from drying out. They are used in office buildings, warehouses, homes, and other facilities with dry air. Portable humidifiers treat a single room or area and can be moved to where they're needed. Duct-mount humidifiers install between the supply and return air ducts in an HVAC system to humidify all the rooms connected to the system. Humidifier pads install into humidifiers. They hold water and release it into the air that passes through the humidifier.