Nov 01, 2017

How do AC Systems Work?

By: support

Your air conditioner keeps your home cool when the summer heat turns up. But have you ever wondered how your AC unit works? Below are the components of your AC unit and how they work together to keep you cool when the temperatures rise.


That refrigerant is what goes through the system’s cooling tubes. It will change its state from gas to liquid while collecting the heat from your home and getting rid of the heat, sending it outside.

It’s very unique, since its boiling point is very low. What this means is that refrigerant will change from liquid to vapor at temperatures that are low. This is the way that your AC will safely work without creating a lot of heat.


The AC unit’s compressor is kind of like its heart, and it pumps refrigerant through the components of the refrigeration system in a huge copper loop. The refrigerant will enter your compressor as a warm vapor at low temperature and then exits it as a hot vapor at high pressure.


After the refrigerant leaves your compressor, it goes to the AC unit’s condenser. Here the vapor gets cooled due to the compressor’s fan blowing air over the condensing coils with fins on them. To help these fins in shape, fin combs are a great choice. As your refrigerant becomes cooler, it goes from a vapor that is hot to a liquid that is hot at a high pressure and then moves onto your expansion valve. Your compressor and your condenser coil, along with your condenser fan are all found in your condensing unit.

Expansion Valve

Your expansion’s valve is really the thing that does all of the work. As the hot refrigerant in liquid form is passing through a really small opening at a high pressure on one of the valve’s sides, it comes out in mist form on its other side at a low pressure and cool temperature. This is what happens when gas expands, it will cool. What an air conditioner does is force your refrigerant to expand. This is what allows it to cool the air. Now there is a cool liquid mist that is low-pressure that will move on your system’s evaporator coil.

Evaporator Coil

That cold liquid leaving your expansion valve will now run through your evaporator coil that is found in your furnace’s plenum.

Here your home’s hot air blows over your evaporator coil, heating it up. While this is happening, the coil that carries expanded cold refrigerant gas will cool off that air that blows over it, sending it back into the house. As your refrigerant is heating up, it’s boiling and changing from the cold liquid, evaporating and becoming warm vapor. Then it goes back to the compressor and the outside condensing unit, continuing the cooling cycle.


In order to work properly, it’s important that you are maintaining the AC unit as you do any other section of the HVAC system of your home. There are things you can do on your own and there are others that require a professional. If you’re not sure, it’s good to refer to your owner’s manual or call a professional.

Air Conditioning Professionals

Boyd Brothers HVAC is built on integrity, professionalism and doing the job right the first time, every time. Growing up in Southwest Florida, we understand that having a broken heating or AC system is about the last thing you want to deal with, or wait around to have serviced.

We have the utmost respect for you, your home, and your heating and cooling needs. We look forward to earning your business through top-quality repair and installation work. Contact us today!

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