Conversely, a humidifier will increase the humidity of a constructing. With the split system, the evaporator coil is linked to a distant condenser unit using refrigerant piping between an indoor and outdoor unit as an alternative of ducting air instantly from the outdoor unit. Indoor units with directional vents mount onto partitions, suspended from ceilings, or fit into the ceiling. Other indoor units mount inside the ceiling cavity in order that quick lengths of duct deal with air from the indoor unit to vents or diffusers across the rooms. These are put in throughout a constructing to maneuver air in or out of rooms. In the center is a damper to open and shut the vent to allow kind of air to enter the area.