Understanding the Parts That Make Your Home’s Air Conditioner Function

An air conditioner incorporates many critical parts. Not a single one manufactures coolness. Instead, the entire function of an air conditioner is to transfer heat. The cool comfort you feel inside your home after all components have done their job is simply a convenient byproduct of efficiently moving indoor heat outdoors. It’s not a simple process. In most residences, there’s no more complex mechanical device than the common central air conditioner.Understanding the Parts That Make Your Home's Air Conditioner Function

Here’s how the symphony of parts play together.

Evaporator Coil

Heat transfer starts here as refrigerant vapor circulating through the indoor evaporator coil absorbs heat from household air blown through coil passageways. The evaporator also condenses humidity from the air, enhancing the cooling process. Vaporous refrigerant then flows from the indoor unit through an insulated line to the outdoor component.


Warm air is drawn out of living spaces through return ducts by the blower, pulled through the system’s air filter, then pushed through the evaporator coil. After heat energy is extracted, the blower disperses cooled air back to individual rooms through supply ducts.


Refrigerant flowing from the evaporator coil is sucked into the compressor installed in the outdoor half of the system. The compressor concentrates heat energy extracted from the house, converting refrigerant into a hot gas.


Hot refrigerant flows into the condenser coil and coverts to a liquid state, rapidly releasing its load of concentrated heat energy through coil surfaces. A coil fan built into the unit blows through the condenser passageways to disperse released heat into outdoor air.

Expansion Valve

The flow of refrigerant loops back indoors to the evaporator coil. Forced through the tiny orifice of an expansion valve, the liquid refrigerant converts again to a vaporous state, ready to absorb more heat from your home.


The thermostat actuates the system blower and compressor to cool the house to the desired temperature setting, then cycles the system off. As the house warms up, the thermostat activates the system again.

For questions or issues concerning the complex parts of your air conditioner, contact the professionals at Amarillo Air Conditioning.

Our goal is to help educate our customers in Amarillo, Texas about energy and home comfort issues (specific to HVAC systems). For more information about air conditioners and other HVAC topics, download our free Home Comfort Resource guide.

Credit/Copyright Attribution: “cherezoff/Shutterstock”