A compressor and condenser coil housed in a unit outside your home. An expansion valve and evaporator (also called an "A coil") mounted above the furnace heater inside your home's heating, ventilation and air conditioning (HVAC) system. An air conditioner works by cycling refrigerant from gas to liquid and then to gas again through the use of pressure. Refrigerant (known as R-410A) begins the cycle as a low-pressure, low-temperature gas that enters the outside unit where it’s compressed into a high-pressure, high-temperature gas. Next, it enters the condenser coil where the fan cools the gas into a high pressure liquid that flows through tubing to the HVAC unit. There it first enters the expansion valve which limits the flow of the liquid as it enters the evaporator. This valve lets the liquid expand into a gas inside the evaporator coil, chilling it as air from the HVAC blower moves over the coil. The refrigerant then heads back to the outside unit as a low-temperature, low-pressure gas to begin the cycle again.

Air is cooled by being blown over the chilled coil and it is then circulated throughout your home. The AC system continues running until the desired temperature is reached. Your home is both cooled and dehumidified by a central air conditioning system. [ Don't let the heat get to you - cool off with a quality air conditioner - learn more here ] Choosing the right size unit Size is a key factor to performance and efficiency of your HVAC system and depends on: Total volume of your home's living space - not just the square footage Area of sun-exposed exterior walls Number, age, condition and orientation of windows Amount of shade from trees and shrubs Amount of sunshine on your home Age of your home Degree of air sealing - amount of insulation Existing ventilation system and ductwork A correctly-sized air conditioner should run a proper full cycle and ensure your home stays cooler longer.It will run for too short a time, too often and cost too much.