How Air Conditioner Work

How Air Conditioners Work

A Step by Step Guide for those of us who are Curious

Growing up in New Jersey, we have hot, humid, muggy summers. The only way to find relief from the heat is to either escape to the Jersey Shore or to hand out inside in Air Conditioning. I always asked myself how air conditioners work. Well I have just discovered the wonderful science to one of the greatest inventions of the 20th Century.

Gas to Liquid back to Gas

If you have a box in your backyard, you probably have air conditioning. A liquid evaporates inside of the house and is turned into a gas (moisture). When the coils blow cold air into the house it is a continuous cycle. Moisture always turns into a gas and then a liquid hence the reason why you have a puddle of water outside of your house when you air conditioning unit is turned on. The whole idea is to remove the moisture from the house by turning the gas into a liquid. The cycle keeps on repeating itself.


The coils are a part of the master plan for air conditioning. There are two kinds: evaporator coils and condenser coils. Evaporator coils are low pressure coils that absorb heat as it changes from liquid to gas when it is hot air. The condenser coils allow the extra heat to be sent outdoors, hence the puddle of water that drips from a tube or pipe outside of your house.


The Parts of an Air Conditioner

Besides coils, there are other parts of the air conditioner that make it cool the air in your house. There is a compressor, hot coils, cold coils and the expansion valve in between the two coils. There are also additional parts such as the thermostat to regulate the temperature and dehumidifiers to lower the humidity.

Window Unit

For the houses that are a bit older, some will have air conditioning window units instead of central air. These are set up a bit differently than a traditional air conditioning unit.

Window and Split-system AC Units
  • Size is smaller
  • Has a compressor
  • An expansion valve
  • A hot coil on the outside
  • A chilled coil on the inside
  • Two different fans
  • A control unit (since it doesn’t have a thermostat)

It is the same where the fans blow the air over the coils to cool the air inside. It is only strong enough to keep one room cool. People usually have them in their bedrooms and living area.


The whole point for the air conditioner is to remove moisture and humidity from a room or house. It does this by absorbing the moisture through one coil and blasts out cold air through the other coil to make the room less humid.

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