How Does an Air Conditioner Work?

Posted 05-11-16 in Air Conditioning

Many people mistakenly think that their AC works by “creating” cold air. They don’t. Instead, they work by removing the heat inside your house and transferring it outdoors.

So how exactly does this process work?

How an air conditioner moves heat outside

Heat inside your home is absorbed and transferred outside via a cooling agent, or “refrigerant”. The refrigerant is contained inside coils that travel through a closed system. The coils guide the refrigerant from inside your home to the outdoors and back inside again.

Stations along the route manipulate the state, pressure and temperature of the refrigerant so that it absorbs or rejects heat at specific points. These stations include:

  • Evaporator
  • Compressor
  • Condenser

Let’s take a closer look at this process:

AC refrigeration cycle

Photo Courtesy of Energy Vanguard/Allison Bailes

Step 1: Heat is absorbed by the evaporator coil
The warm air inside your house is drawn in through a vent and blows over the cold evaporator coil. The evaporator coil is the station located indoors and absorbs heat from the air, cooling the air. A fan blows the cold air into air ducts that distribute it throughout your home.

How an air conditioner cools your home

As the refrigerant absorbs the heat from the passing air, it changes from a liquid state to a gaseous state and continues to travel along the loop system toward the compressor.

Step 2: Compressor raises the refrigerant temperature
The compressor decreases the gas’ volume. Usually this is done by squeezing the gas tightly between two solid objects.

This raises the pressure and temperature of the refrigerant, preparing it for the condensing process. 

Step 3: Heat is transferred outside
The refrigerant, now a superheated vapor, reaches the condenser (which is located outdoors) and is exposed to the outside air. The outside air absorbs the heat from the refrigerant, lowering the temperature of the refrigerant and changing the state from a gas back into a liquid.

Step 4: Refrigerant gets cold; process repeats
Once the heat from the refrigerant is removed to the outdoors, the cold refrigerant travels back indoors to the evaporator to repeat the process over again. The process continues until the inside temperature of your home reaches your desired level. At this point, your thermostat tells your AC to shut off.

Further reading about air conditioning


Coolray is your Atlanta-area home comfort expert with specialists in heating, air conditioning, air quality and plumbing. Have more questions? We’d be happy to help – just contact us online

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