A central air conditioner system is made up of three important parts: evaporator, condenser, and compressor.
In this article, No Problem Heating & Cooling is going to run you through how a central air conditioning compressor works, what you can do to maintain the system, and what kind of costs to expect if you need to replace the AC compressor.
What is an Air Conditioning Compressor?
While your AC compressor is located outside, it is really the heart of your AC system. Your compressor works the same way your heart does. The central air conditioning compressor is responsible for pressurizing and circulating the refrigerant, which enables the transfer of heat from inside your home to the outside environment, resulting in a cooler and more comfortable indoor temperature.
How Does Your Central Air Conditioner Work?
The compressor will pump refrigerant from your outside unit to the indoor unit. At this point, the refrigerant is cold, but it starts collecting heat and as it gets hot it turns into a vapor. At some point, it will not be able to grab any more heat and it travels back toward the compressor outside. Remember it is pulling that heat back with it. The refrigerant comes back to the outdoor unit as a superheated gas. Once the refrigerant loses this heat, it goes right back inside to start this process over again.
How to Keep your Central AC Compressor in Good Shape
Keeping your system in tip-top shape is going to help prevent most issues. No Problem Heating & Cooling offers a club membership that will keep your HVAC system protected all year long. Keeping your outdoor unit clean will be a big help. You will want to clean your system yearly outside. Pull your covers off and spray the dirt and bugs off on the condenser fins.
We see a lot of trees and shrubs that cover AC units that cause major problems with the system. Do not ever buy a decorative cover for your AC! If have trees, shrubs, or barriers that covers too much, it will suffocate your system.
What are the Signs of Low Refrigerant in My Central Air Conditioner?
Watch for low refrigerant. If your system is low on freon, the compressor will work harder to push enough refrigerant through the system to cool down your house. Possible signs could be:
- The copper lines are warm
- There is icing on your coils
- Bubbling or hissing noise from your lines
- Higher electric bills monthly
- Warmer air instead of cooler air coming from your indoor vents
- The AC will run constantly and not cool your home
It’s important to note that if your system uses an older type of refrigerant like R-22, you may need to upgrade to a more environmentally friendly refrigerant like R-410A. This can add several hundred dollars to the cost you may be expecting from past experiences.
How to Check for a Bad Compressor
If you are hands on and love the technical stuff, David Jones takes you through how to check for a bad compressor in this video:
For your safety and to maintain any available warranties, only a licensed HVAC technician should perform any work on your HVAC system.
How Much Does It Cost To Replace an AC Compressor?
The cost to replace a central air conditioning compressor can vary widely depending on several factors, including the size of your AC unit, the type of refrigerant it uses, your location, and the labor costs in your area. On average in the St Charles/St Louis area, you can expect to pay anywhere from $500 to $2,000 for the compressor replacement.

Can I Replace the AC Compressor or Do I Need a New One?
This is a tough question. AC compressor failure is fairly common when it comes to a whole system failure. Since the air conditioning compressor is crucial to the function of your AC system, generally the cost of replacement can get high. One of the biggest factors to determine if you should buy an entirely new air conditioning system is how old your current system is. The HVAC technicians at No Problem Heating & Cooling will go over the specific pros and cons with you. Fortunately, there are many rebates and tax credits available for installing select high-efficiency units.
If you have questions about an air conditioner compressor, or if you need service for your air conditioner or need one installed, call No Problem Heating & Cooling!
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Jeanne24 September 2026Trustindex verifies that the original source of the review is Google.
Needed furnace to be checked out for the winter. Casey was very nice and explained everything thoroughly. I am very pleased with the service I received.Posted on Google![]()
Jeff24 September 2026Trustindex verifies that the original source of the review is Google.
The team at no problem heating and cooling did an excellent job installing my new Mitsubishi mini split from start to finish, l am very happy with the completed project and the way everything was handled and the communication was above and beyond great. I would definitely use them again and refer them to all my friends and family. Thanks again for doing a great job. I will be using them from here on out for all my HVAC needs.Posted on Google![]()
Patrick Gateway21 September 2026Trustindex verifies that the original source of the review is Google.
Fast and efficient, tech was very knowledgeable, fixed the issue less than 4 hours after I called them to make the appointmentPosted on Google![]()
Jada Campbell18 September 2026Trustindex verifies that the original source of the review is Google.
We had a great experience with No Problem Heating and Cooling! My AC went out, and they were able to get me scheduled quickly after I called. They came out, figured out what was wrong, and explained my options without being pushy about selling me anything. I ended up repairing my current AC but when it’s time to replace it, I’ll definitely be calling No Problem again. They also told me about their air purification systems, and with my allergies, I decided to have one installed. I’m really looking forward to having cleaner air in the house. Thanks for everything! Great service, honest recommendations, and super easy to work with. I definitely recommend No Problem!Posted on Google![]()
Martha Hogan14 September 2026Trustindex verifies that the original source of the review is Google.
Casey k. Did a awesome job and we are very pleased 😁Posted on Google![]()
Laura Ray11 September 2026Trustindex verifies that the original source of the review is Google.
Casey and Donna both worked so hard to get our air conditioner working and back to normal. I cannot tell you how much it meant to my husband and I. When Casey walked into our home, it was almost 90 degrees, and thanks to both of them - less than 12 hours later - it was a perfect temperature. Even while experiencing a heat wave, our air conditioner works perfectly! THANKS TO DONNA for arranging his crazy busy schedule to fit us in as an emergency and THANKS TO CASEY, for his knowledge and expertise on how to fix the problem in less than an hour. I WILL ALWAYS YOUS NPM HEATING & COOLING LLC, and will recommend them to all of our family and friends. I can't tell you how grateful we are. Thanks again. Laura RayPosted on Google![]()
Lindsay Burle9 September 2026Trustindex verifies that the original source of the review is Google.
Service was fast, professional, and they did a great job!Posted on Google![]()
Sara Fager9 September 2026Trustindex verifies that the original source of the review is Google.
Very skilled, professional and on time. Did a great job on a new system. Good communication process and very responsive. I highly recommend.Verified by TrustindexTrustindex verified badge is the Universal Symbol of Trust. Only the greatest companies can get the verified badge who has a review score above 4.5, based on customer reviews over the past 12 months. Read more
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