Skuttle 86-UD is a whole-house central humidifier designed to improve indoor air quality by adding moisture to the air. It is equipped with a drum motor that rotates a polyurethane foam evaporator pad, lifting water into the dry air stream from the water pan. The moist air is then circulated throughout the home by the heating system. The unit includes a humidistat that allows you to set the desired humidity level, and it has a low-voltage solenoid that controls the flow of water to the evaporator pad.