Let's break it down step by step: a. The built-in humidistat senses when the humidity goes above your set level and turns the unit on. b. The fan pulls in air through the grille. c. That air passes over cold evaporator coils causing moisture in the air to condense. d. The water drips into a drain pan, and the now-dry air moves on to the condenser coils. e. The condenser coils warm the air back up to its original temperature before releasing it back into the room.