The evaporator cools and humidifies the air before the air enters the vehicle. High pressure liquid refrigerant flows through the orifice tube into the low-pressure area of the evaporator. The heat in the air that passes through the evaporator core is lost to the cooler surface of the core, thereby cooling the air. During this time, any moisture (humidity) in the air condenses on the outside surface of the evaporator core. The condensed moisture is drained off as water.