How Does An HVAC System Work?
An air conditioner’s compressor contains a refrigerant. As it works, it sends this refrigerant through the system. As warm air blows across the coil that carries this refrigerant, the heat transfers to the refrigerant (cool always absorbs warm). A fan moves the cooled air through the ducting and out of vents that lead into the rooms of your house. The refrigerant returns to the compressor where the absorbed heat is moved outside. The refrigerant is then sent through the coil once again to continue the cycle.
In a split system, the heater or furnace will be located away from the air conditioner. It may be in a garage or a basement. In a package unit, sometimes called a “gas pack”, the heater is in the same cabinet as the air conditioner. All heating systems will have four elements in common:
- Burners that burn fuel and deliver it
- Heat exchangers
- A blower that pushes the air along
- An exhaust flue
In a manner similar to the coil described above in the cooling section, the burners heat up the fuel and send it through the heat exchanger. Cool air blows across the heat exchanger and absorbs the heat. The blower then sends it through the ducts and into the rooms of your house. The flue sends any exhaust gases safely out of your house.
All of this is controlled by the thermostat as it communicates with your HVAC system’s circuitry. It tells the system when to heat, when to cool, when to stop and when to run. Some systems control the temperature according to the whole house while others can control it room by room.