Air conditioning is often used to mean cooling, but it can also refer to heating or ventilation of the indoor environment. When in ‘cooling mode’ an air conditioning system moves heat from one area to another effectively cooling down the air in the room. It works by driving refrigerant through two coils; one hot and one cold. The warm air in the room is taken over the cold coil, which cools and dries it. This cool air is then returned into the room and the hot air is expelled outside or into another space.