What Does a Central Air Conditioner Compressor Do? A Florida Tech Explains.

February 15, 2017


Your compressor is the “heart” of your entire AC system. Without it, your air conditioner wouldn’t be able to produce a single gust of cool air.

But, of course, that’s a barebones explanation. We’ll take a more in-depth look at exactly what your AC compressor does and give you tips on keeping your compressor in tip-top shape.

A behind-the-scenes look at what your compressor does

So how exactly is your compressor the “heart” of your AC system? Well, just like your heart pumps blood throughout your body, the compressor pumps refrigerant throughout the AC system.

Refrigerant is the fluid that absorbs heat from inside your home and carries it outside (much like blood absorbs and carries oxygen throughout the body).

Here’s a more in-depth look at how your AC uses refrigerant to transfer heat and the role your compressor plays in this process:


Step 1: Your compressor pumps refrigerant from the outdoor unit (condenser) to the indoor unit (evaporator). During this stage, the refrigerant is a cold liquid that absorbs heat from inside your home.

As it collects more and more heat, the liquid refrigerant begins to turn into a vapor. Once it contains as much heat as it can hold, the (now vapor) refrigerant travels back towards your compressor, bringing the heat with it and away from your home.

Step 2: Once the vapor refrigerant arrives back at your outdoor unit, your compressor sucks in the refrigerant and heats the refrigerant up even more until it’s a superheated gas.

And because heat naturally moves to colder spaces, that super hot refrigerant can dump a lot of its heat into the cooler outdoor air. As it loses more and more heat, the refrigerant turns back into a liquid.

Step 3: Once the refrigerant loses most of its heat, your compressor sends it right back to your indoor unit to repeat the process until your home is cooled to your desired temperature.

It’s a bit more complicated than that, but that’ the gist of it!

4 tips to keep your compressor in good shape

Because the compressor is valuable, it’s also very expensive (it can cost upwards of $1,875 to replace it), so you’ll want to keep it in good shape so that it lives a long time.

While compressors can typically live anywhere from 10 to 15 years, if you don’t keep your outdoor unit well maintained, your compressor can die much sooner than that.

So, to keep your compressor in good shape, consider these 4 tips:

1) Don’t suffocate your outdoor unit.

Go outside and check your outdoor unit. Make sure that all shrubbery, tree limbs, fences, etc. are at least 3 feet away from the unit. Never use decorative air conditioner “covers” either. Basically, anything that closely surrounds your outdoor unit prevents it from properly dumping heat into the outdoor air, causing your compressor to overheat and die.

Related: Why You Should NEVER Cover Your Air Conditioner

2) Clean the condenser fins regularly.

Any buildup of dirt, bugs, etc. on the condenser fins can also impede the “heat dump” process and damage the compressor. The best DIY method for cleaning your condenser fins is to grab an “AC-safe” coil cleaner like this one. Just follow the directions on the bottle and rinse the fins off with a hose on a gentle setting when you’re done.

Related: You Should Clean Your Home’s Air Conditioner (Unless You Like Losing Money)

3) Recognize the signs of low refrigerant (and act quickly!).

If your system is low on refrigerant (due to a refrigerant leak), your compressor will have to work harder to circulate enough refrigerant through the system and cool down your home. If you notice any of the signs below call a professional as soon as possible to fix the leak and recharge the system.

Signs of low refrigerant include:

  • An AC that runs constantly and still can’t cool your home

  • Higher-than-normal energy bills

  • Ice or frost on refrigerant coils

  • A hissing or bubbling noise coming from refrigerant lines

4) Schedule regular AC maintenance visits.

Having a professional inspect and maintain your air conditioner twice a year will help keep your compressor in tip-top shape. (And you don’t have to lift a finger!)

Need professional maintenance to protect your compressor (and comfort)?

Want to avoid a costly compressor replacement?

Our professional techs keep your compressor healthy for higher comfort and lower cooling bills.

We even offer our CoolClub Maintenance Agreement Plans for money-savvy homeowners who want to extend the life of their HVAC systems.

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