An Air Conditioner seems as if it cools your home's Air, but it actually makes your home less warm by removing heat from the indoor Air and transferring that heat to the outdoor Air. Heat is extracted from the home by passing indoor Air across a refrigerant coil in the indoor unit. Refrigerant lines then carry the heat to the outdoor unit, where it is released into the outside Air. The cooling cycle continues until the indoor temperature reaches the thermostat setting.