How a Central Air & Heating Unit Works

Cooling System

Most central cooling and heating systems are partially split systems that include an outdoor metal box holding condenser coils and a compressor to support the air conditioning features.This exterior condensing unit is piped to an interior system that houses the evaporator coils of the air conditioner.

The evaporator coil unit is located adjacent to or in the same unit as the heating furnace and air handlers. Air is cooled as it's blown over the air conditioning cooling coil, which is filled with refrigerant, and the heat is transferred to the refrigerant, which produces condensation as a by-product. The cool air is then blown through the air handlers and through the system of air ducts and vents throughout your home.

Heating System

Central heating means that you have a single centralized furnace which generates heat for the entire home. It is always placed in a protected location in the home, most often in the garage or basement. Every furnace performs similarly: It burns fuel (gas, oil or both), exchanges heat, blows hot air and has an exhaust system or flue vents to eliminate any gaseous fumes. Cool air is warmed by being blown across the heat exchanger in the furnace and then is blown into the duct and venting system shared with the A/C unit that runs throughout the home.

System Links

Installed, the exterior A/C compressor is piped into the coil cooling system in the garage or basement and then linked up to the same air handlers, blowers, exhaust vents and fans that are connected to and used by the heating system. The two elements of the system also share the extensive array of duct work that runs through the home delivering warm or cool air to every room in the house.