How an Air Conditioning System Works

You may have pondered how an air conditioning system actually works, or perhaps you have never given it a moment’s thought. Just in case you are curious, we will attempt to explain it to you.

Air conditioning like it says, “conditions” the air. It not only cools the air down, but it also reduces the moisture content, or humidity. Refrigeration cycle plays an important part in this. This cycle works the same way whether an HVAC system is installed in a building, in a car, or even a household refrigerator. Air conditioning is a field in its own right but we’ll stick to the main points.

A number of people don’t realise that turning on the air conditioner actually reduces the number of miles per gallon of your car. Because the compressor runs, there is excess energy used in removing the heat and moisture from the air inside the car, which consumes more gasoline because of the extra engine load. Nevertheless, your car basically has the same type of AC that your house does.

Refrigeration Cycle

Air conditioning’s main principles are evaporation and condensation. It repeats the cycle of compression and expansion. It pretty much is a science experiment happening in your home. At a simpler level, it absorbs heat and throws it outside.


You may have noticed that if you rub a little bit of surgical spirits on the back of your hand, your hand will feel cool. Why is that? It’s evaporation. It is because the spirits on the back of your hand start to evaporate. As these spirits evaporate, it takes away heat from the surface of your skin. This is basically the role of the evaporator in your air conditioning system at home.

The Process of Cooling your Home

Your air conditioning unit uses refrigerant, some people call it freon, that converts from gas to liquid and back again quickly. This refrigerant transfers the heat from inside of your house to the outside air.

The air conditioner appliance has four key elements. They are the compressor, the condenser, the metering device, and the evaporator. You unit’s compressor and condenser are typically located at the outside area of the air conditioning system. Inside your home, perhaps the attic or in a closet, is where you will find the evaporator with the air handling unit.

How Your Air Conditioner Removes Hot Air & Blows Cold

The refrigerant enters the compressor as a low temperature, low pressure gas. Once it is “compressed”, it leaves the compressor as a high temperature, high pressure vapor and moves to the condenser. The condenser is the outside unit that has metal fins all around the housing.

When the fluid leaves the condenser, it actually “condenses into a liquid” It then moves to the metering device and becomes much cooler. Finally entering the evaporator through tiny tubes. The pressure drops and the liquid turns to gas. This gas goes back to the compressor as a low temperature, low pressure gas and repeats the cycle.

If you are still confused, I will explain it in a simple way. Imagine a dry sponge that is dipped in water and absorbs a good amount. Then the sponge is removed from the water is squeezed to remove the water outside of the bucket. The water is heat absorbed and removed leaving cold air.


Air conditioning systems are a wonderful invention. They keep us comfortable during extreme seasons and help us sleep better at night. HVAC systems are misunderstood and learning about them can be quite interesting.

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