How Does an Air Conditioner Work?

By Dave Donovan

An air conditioner requires three components to cool air in a home--a compressor, condenser and evaporator. The job of each component is essential to the effectiveness of the air conditioner. In most cases, the air conditioner's compressor and condenser is located on the outside of the home, while the evaporator is located inside, normally within the furnace.

The air conditioner system uses a refrigerant that travels through the components. The refrigerant is a liquid and gas mixture. When the refrigerant enters the compressor, it gets compressed, which causes it to become heated. As it heats, the refrigerant is transformed into a high-pressure gas. Once compressed into this gas form, the refrigerant then enters the condenser.

The condenser removes the heat by rapidly condensing the refrigerant into a highly pressurized liquid. Now the refrigerant gets extremely cold and is sent into the coils of the evaporator through a very small hole. Upon entering the evaporator, the liquid quickly begins to evaporate back into a gaseous state due to the extreme drop in pressure.

During this time, the evaporator's fan draws air from inside the home. The system's blower motor pushes air over and through the coils; the air gets cooled and dispersed throughout the home. As the warmer air is pushed through the cold coils, it releases its moisture which is called condensate. The condensate is collected in a condensate pan and is normally removed by a pump that pumps it down a drain in your home.

After the refrigerant returns to its gas state in the evaporator, it then makes its way back to the compressor, which starts the process all over again. This continues until your home's thermostat reaches its set temperature.