What is the AC Compressor?

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Updated February 3, 2023

If you are new to the world of indoor cooling, you may wonder what is the compressor on an air conditioner. The vast majority of the best air conditioners, after all, feature a compressor as a primary component. So what is the compressor, what does it do, and how does it benefit your favorite AC unit? Keep reading to find out.


  • An air conditioner’s compressor is a vital component that is referred to as the “heart” of the AC unit.
  • The compressor converts power into energy and moves liquid refrigerant throughout the condenser coils, the evaporator coil, and other parts of outdoor units.
  • Air conditioner compressors are susceptible to certain repair issues, such as those caused by refrigerant leaks and electrical problems.

What Exactly is an AC Unit’s Compressor?

The compressor converts power into energy and circulates the refrigerant necessary for indoor cooling. Simply put, without the compressor, you won’t have cold air, even if you have learned what type of freon for a home air conditioner. This component is called the “heart” of an air conditioner for good reason, even if you already know what is a package unit air conditioner. This is a crucial component even if you have learned what causes freon leaks in an air conditioner.

Insider Tip

You should also keep your air filters clean to allow the compressor to do its work undisturbed.

Some version of a compressor is found in nearly every AC design, from portable air conditioners to central units and beyond. If you are wondering what kind of oil you need for an air conditioner, the answer is none at all, as most AC units use freon.

Common Compressor Issues

Compressors are not only a vital part of the air conditioner, but they are also expensive and relatively finicky pieces of technology prone to repair and maintenance issues. Here are some of the common repair issues that impact modern AC compressor units.

STAT: The compressor can be found in the outdoor air conditioning unit, at the rear, or on the side of your home. Other important parts within the outdoor unit include the condenser, condenser coil, and fan. (source)

Electrical Problems

Compressors use a lot of electricity, along with the motor, and are at risk for certain electrical issues during use. These electrical errors build up over time, eventually damaging the compressor and the rest of the system. Hire a professional technician to inspect your system for acids and any electrical damage to fuses, wires, and the body of the compressor itself.

Refrigerant Leaks

Most compressors are susceptible to damage related to refrigerant leaks. Over time, your air conditioning unit’s refrigerant lines develop cracks and holes, leading to leaks. As the refrigerant spills out, the compressor has to work harder. This eventually causes a system-wide failure. Hire a pro for an annual inspection to catch leaks before they become a larger problem. A good warranty will also come in handy if you run into these issues, like the great warranty featured in our Goodman air conditioner review.

Too Much Refrigerant

Avoid filling the system with too much refrigerant, as this eventually causes damage to the compressor as the system struggles to deal with the excess liquid.


How do ACs work?

AC units feature an air conditioning compressor and a condenser unit, among other components, to complete the cooling process. A faulty compressor or broken compressor in an indoor unit or outdoor unit leads to system failure.

Why is my compressor so difficult to repair?

AC compressors are complicated, making for a difficult air conditioning repair process. This is due to the nature of modern air conditioner unit compressor designs.

Is this the end of the line for your air conditioner?

In the case of air conditioner compressor failure, you may want to purchase a new AC system, as replacement parts and repairs are costly. However, talk it over with your pro.

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