What’s Inside Your AC Unit? A Beginner’s Guide

Your central AC system is made up of four major parts that work together to keep your home cool and comfortable. Let’s take a closer look at each component:

1. Evaporator Coil

This part is located inside the AC handler and helps to absorb heat, cool and dry the air, and circulate it through the ductwork in your home.

2. Compressor

Found in the outside cabinet alongside the evaporator coil, the compressor is responsible for converting the refrigerant into a denser form, which increases its temperature.

3. Condensor Coil

The condenser coil releases heat from the refrigerant and is located alongside the compressor. While the evaporator coil absorbs heat, the condenser coil expels it, causing the refrigerant to turn into a hot liquid.

4. Expansion Valve

The expansion valve reduces the pressure of the refrigerant, turning it back into a cold mist and removing excess heat.

The Process Explained

So how do all of these parts work together to keep your home cool? The process begins with cold refrigerant entering the evaporator coil, drawing latent heat from the air and causing the refrigerant to transform from a cold mist into warm vapor. The warm vapor is then compressed into a denser form using the compressor, increasing its heat and pressure. The pressurized refrigerant then moves into the condenser coil and turns into hot liquid using air brought in by the condenser fan. Finally, the refrigerant changes from liquid back to vapor due to a great pressure decrease in the expansion valve, expelling excess heat at the same time. This process is repeated consistently to keep your home cool.


Now that you understand the different parts of your AC system and how they work together, it’s important to know how to maintain your system. There are a few things you can do from home to help keep your system up and running. Any at-home maintenance should be done carefully to avoid damaging any of the components. For example, removing blockages around the exterior of the condenser can help improve its efficiency.

For more advanced maintenance procedures, it’s crucial to shut the power off both near the condenser and at the breaker box to avoid any potential injury. Using a wrench or screwdriver, the fan cage can be removed, and any debris inside the unit can be removed by hand or vacuum. You can also remove the outer covers and use a brush attachment on a vacuum to remove any buildup on the sides of the unit. Be sure to use a gentle hose stream to spray through the fins from the inside out to remove any debris stuck between them, as high pressure can damage the unit. Any visible dirt buildup can be carefully cleaned and dried, and fins on the side of the unit can also be straightened. While parts such as filters can be replaced, it’s recommended that a professional technician is called for more complicated procedures.

In summary, understanding the different parts of your central AC system and how they work together is essential to keeping your home cool and comfortable. By performing proper maintenance and leaving more complex procedures to the professionals. Give Service Patriots a call for more information!

Share This Post

More To Explore