The only other main part of the system is the evaporator unit. It is the A/C system component that has the function of removing heat from air injected into the cabin. Another very important function performed by the evaporator is that of dehumidifying the conditioned air.

The evaporator is in front of a fan. The fan pulls out the hot, humid air of the car's cabin. The refrigerant makes the hot air's moisture condense into drops of water, removing the heat from the air. Once water is removed, the "cool" air is sent back inside the car. The system has two built in switches, one that stops the compressor if the pressure is too low, and one that prevents ice from forming on the cold evaporator, as both of these faults can damage the system.