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What Makes an Air Conditioner Work? Part 2: Operation

We’re exploring what makes an air conditioner work. It’s one of the things we take for granted – until it breaks, that is.

If you read [Part 1], you know that your air conditioner cools air by removing heat. That’s why you might have heard an air conditioner described as a heat pump.

Now, let’s go through the 2 steps of what makes an air conditioner work.

 Step 1: Compression

Your air conditioner’s compressor constantly fills the condenser with more and more of the refrigerant in its gas state. It forces the gas in there, so that the gas particles have no choice but to move closer to each other. As they get closer, the gas condenses into liquid. That’s known as a phase change. In fact, “phase change” is the term used to describe the technology.

During compression, the condenser coil radiates heat from the refrigerant. Fins attached to the condenser give it greater surface area to transfer heat to the air. This aids condensation of the refrigerant, since cooler gases can more easily condense.

The condenser fan helps to speed up the cooling process. It passes air over the condenser coils. Cool air absorbs more heat than warm air. And as the refrigerant gas’ particles get closer together, the refrigerant lets off heat.


After the refrigerant is condensed, the compressor continues to force more gas-form refrigerant into the condenser. That pushes the liquid refrigerant out of the condenser through one of two parts: either the capillary tube or the expansion valve. (Not all air conditioners use the same part for this step of the process.) Both the capillary tube and expansion valve lead into the evaporator and restrict refrigerant flow.


As refrigerant is pushed into the evaporator at low pressure, the refrigerant evaporates quite fast. And evaporation makes the refrigerant absorb heat. The more quickly it evaporates, the colder it gets. Remember the term, “phase change?” This is phase change #2.

Next, the blower fan pulls air from your home through the cold air return. It blows the air over the evaporator coil, cooling it.

Now in gas form again, the cold refrigerant soaks up heat from the evaporator coils. As it moves into the compressor, it goes on to absorb heat from the compressor as well. That cooling action extends the compressor’s lifespan.


So, now you know what makes an air conditioner work! The air conditioning process is a fascinating one – and understanding it helps us to see how each and every part is crucial. If your compressor, condenser, or evaporator goes, the whole machine is useless.

That’s why it’s so important to have regular maintenance done on your air conditioner. What makes an air conditioner work is really proper maintenance.

Because even if your unit is still running, if it’s not properly maintained, the cooling process will be less efficient. It’ll cost you money and break down sooner.

Just Call Dale’s for the peace of mind that comes with professional air conditioner service. We’ll be happy to keep you cool and comfortable – all summer long.