Parts of an AC Unit

Jul 2nd 2021

Air Conditioner Parts and Functions

The following elements make up the various parts of an AC unit. If one or more of them is not functioning, neither will your air conditioner. Fortunately, you can find all the air conditioner components you need at HVAC BRAIN.

Condenser Coil

The condenser coil has hot refrigerant in it and can generally be found on outdoor air conditioning units. It's typically under a tremendous amount of pressure, and its entire function is to send warm air to the outside of your home. This way, your home stays nice and cool inside.

The condenser coil sends the hot refrigerant through the expansion valve and flushes it outside. It's one of the most critical AC parts, and if it's not functioning correctly, your air conditioning unit will not work right.


Perhaps the most crucial part of your air conditioning unit, the refrigerant is what makes the whole thing run smoothly and adequately. Sometimes you will hear refrigerants referred to as "Freon," a specific brand name. This liquid stimulates the cooling system within your air conditioning unit and helps it pump out cool air.

The refrigerant is completely encased in the parts of an AC unit itself. The closed-loop system allows it to move from inside your home to outside, where the hot refrigerant is distributed. Refrigerants can also change their state. They regularly move from liquid to vapor as they cool the air.

Refrigerant acts as a messenger between the outside and inside of your home. It takes the heat from the air inside your home, sucks it in, changes it back to a liquid form, and moves it outside.

After getting rid of the excess heat from inside your house, the refrigerant goes back to being a gas and comes in. As it chills, your fan blows the cool air into your house. This process is repeated several times as the refrigerant changes from liquid to gas, cooling your home.

Expansion Valve

The expansion valve is one of the air conditioning parts through which the refrigerant must travel when moving from inside to outside. This valve can take the pressure off of the refrigerant, which enters it as a liquid so it can transform back into a gas.

Without this valve working correctly, you will not be able to manipulate the state of the refrigerant, which could cause your air conditioning unit to stop working entirely.

Air Filter

The air filter cleans and purifies the air so that your air conditioner components work properly. Like all appliances, air conditioning units can collect dirt or dust from the air. If this gets into the air conditioner, it could cause problems with the internal features.

Change your air filter often to ensure that you are getting the best, coldest air. If it's clogged, your air conditioner parts and functions won't work as well and might even stop working entirely.

Evaporator Coil

Your evaporator coil is one of the AC parts you can't live without — it helps your air conditioning unit get air from inside the house and move it outside. It's generally made out of copper and helps move the refrigerant outside of the home after it goes through the expansion valve. Evaporator coils only operate correctly if your fan is operational because both help to move the refrigerant.

An AC unit disassembled


Another of the essential air conditioner parts is the blower. It does two jobs: sends cool air into your house and pulls hot air outside. If your blower isn't working at maximum capacity, you could miss out on some of the benefits of having an air conditioning unit by not having enough cool air circulation. If your blower is broken, your air conditioning unit will be completely ineffective.


The compressor works to pressurize your refrigerant and make it warmer. Since the laws of thermodynamics dictate that the more you pressurize something, the hotter it gets, this helps to make the refrigerant as hot as possible. The compressor crushes the refrigerant, which is in gas form, to heat it up.

The idea is that you need to get the refrigerant as hot as possible. To travel outside, it needs to be warmer than the outside is. A compressor is one of those air conditioning parts that's easy to overlook, but it's another vital part of your unit's operation.


Your air conditioning unit's fan helps to make sure that the inside isn't overheating. Its function makes it another of the most important air conditioner parts. Since tons of warm refrigerant passes through it, it could get extremely hot and shut down.

Although you don't specifically benefit from the air conditioning unit's fan, its operation helps keep cool air circulating.


The thermostat is one of the only parts of an AC unit that you can physically control. Often, we can set the thermostat simply by pressing a button or turning a dial that lets it know when it's supposed to kick in. You set the thermostat by dictating what temperature is acceptable in your home. When your home reaches that desired temperature, the thermostat will tell the air conditioning unit to switch off.

As your home naturally heats up, the thermostat will tell the air conditioning unit when it needs to go back on again. Of course, the lower your thermostat is set, the higher your energy bills will be, which is why many people prefer to turn off their units when they're not home.

Find Your Air Conditioner Parts Now at HVAC BRAIN

Understanding the different parts of an AC unit and how they all function together is necessary for keeping your home cool. It's vital to keep all of your air conditioner components working correctly. Whether you need to buy air conditioners or find replacement parts, HVAC BRAIN can help! Check out our selection today and reach out if you need assistance.