Trusted HVAC Service In O’Fallon Since 1977
There are more than a few reasons Jerry Kelly Heating & Air Conditioning has been selected as the winner in the Heating & Cooling service category of the St. Louis Post-Dispatch Best of St. Charles awards 23 times running. In addition to delivering impeccable workmanship and superior customer service to O’Fallon, MO homeowners, we provide:
- Top-rated air conditioning, heating and indoor air quality services.
- Dependable, 24/7 answering system.
- Flexible scheduling to meet your needs.
- Over 50 years of continued education in the field.

Whether you’re in need of a furnace installation, air conditioner repair, or water heater maintenance check, our friendly and professional team will simply make it work. We urge you to read what some of our valued customers have to say about our O’Fallon, MO heating and air conditioning solutions and services on our resources page.
“The HVAC technician was very knowledgeable & identified the issue within minutes of accessing my furnace. He was also able to alert me of maintenance concerns I didn’t know about it. I would definitely recommend Jerry Kelly and the crew to my neighbors!”
Robertson – O’Fallon, MO
Give us a call at 636-757-8506 to schedule heating and cooling service in O’Fallon today!
Yes, Jerry Kelly is an essential service provider during the COVID-19 virus outbreak. This is because Jerry Kelly provides vital HVAC, Indoor Air Quality and Water Heater services that are essential for maintaining the safety, sanitation, and operation of residences and businesses. HVAC contractors like Jerry Kelly have unique skills that are important to public health and welfare.
Jerry Kelly HVAC service technicians who come to your home or business will adhere to the CDC's guidelines designed to stop the spread of COVID-19. Jerry Kelly has enhanced its already strict cleaning and disinfecting measures to ensure the safest possible service experience for its customers and employees, including wearing personal protective equipment, and practicing social distancing. Also, our HVAC technicians are using hand sanitizer in between hand washes.
If your air conditioning unit is not working, there might be a number of reasons why. Some common reasons why include:
- Tripped circuit breaker - Air conditioners typically have an indoor and an outdoor circuit breaker. Make sure your outdoor breaker is not tripped. If you reset it and it trips again, you will need to contact a professional to determine what is wrong.
- Dirty evaporator coils - Dust, dirt and dander can build up on evaporator coils and can cause a total breakdown of the system. Regular AC maintenance can help prevent this from happening.
- Dirty condenser lines - Over time, mold and algae can grow on condenser lines, clogging them and causing the air conditioning unit to malfunction.
- Faulty motor - If the unit had been making unusual sounds before it stopped working, the motor is probably broken.
- Broken thermostat - If the thermostat is not working properly, it can stop the air conditioner from turning on.
For more information on air conditioner troubleshooting, contact Jerry Kelly Heating and Air Conditioning. We pride ourselves on being the premier heating and air company in the O’Fallon area. Call us 24 hours a day, 7 days a week at (636) 757-8506.
You should have an air conditioning maintenance service performed on your unit annually. Regular service will help prevent malfunctions in the future and keep your unit running efficiently and effectively.
After 40 years in the business, Jerry Kelly knows a thing or two about ACs. Contact us online or call us today to schedule your air conditioner maintenance service at (636) 757-8506. You’re in good hands with Jerry Kelly, and we’re proud to serve the community of O’Fallon.
Residents in the O’Fallon area can expect to pay between $150 - $300 a year to have their HVAC system inspected and maintained.
After 40 years in the business, Jerry Kelly knows a thing or two about HVAC units. Contact us online or call us today to schedule your HVAC maintenance service at (636) 757-8506. You’re in good hands with Jerry Kelly.
A few reasons you may want to replace instead of repair your AC unit include:
- Your AC unit is over 10 years old.
- Your AC unit requires many repairs.
- Your AC unit does not cool effectively.
Another reason you may want to replace your AC unit instead of repair it is if the cost to repair it is more than half of the cost to replace it. To get your air conditioning system repaired or replaced, contact us today.
Local Reviews
for Ofallon, MO
Great service!
Deutsch - Ofallon, MO
Tech did a great job and explained everything he did to me




on time and informative
dan - Ofallon, MO
Very satisfied, especially being on time




Great Service!
Barbara - Ofallon, MO
Jeff was knowledgeable, friendly, helpful and thorough.




I was happy to have service early due to a cancellation.
mrs Betty - Ofallon, MO
Your screen is hard to read as the type color is very pale.




Very professional presentation and follow-up service.
Ken - Ofallon, MO
The first service call did a very good job of listing my options in terms of risk and cost. The installation and the system were first rate and so far, the results show I made a good decision. My electric bill went down by half. We also liked the follow-up courtesy call.




Great service. He answered all of our questions.
Joe - Ofallon, MO
We are very happy with our new sur conditioner and heater. The service is phenomenal.




always great service
vee - Ofallon, MO




best service
hodson - Ofallon, MO




quick response
steven - Ofallon, MO




Answered questions and offered suggestions to extend life of unit
Bouchillon - Ofallon, MO
I took his advice




Everyone was very professional and we received a great price!
Joe - Ofallon, MO
We will definitely recommend Jerry Kelly to our friends and family!




Exceptional Service, from Beginning to End!
Mary - Ofallon, MO
I caught the salesman, Bryan Jones, on his day off and he still took the time to give me an estimate and get everything lined up. The installation was very professional and fast. Thank so much for rescuing us from another miserable summer. Mary & Steve




thank you
Matthew - Ofallon, MO




Always a Great Experience!
Chris & Angela David - Ofallon, MO
We wouldn't use or trust anyone other than Jerry Kelly. Always professional, friendly and thorough.




Ryan S.
Troubleshooting an air conditioner that broke down.
Will L.
Repairing an air conditioner that had malfunctioned.

David G.
Doing an a/c startup.
Ronan w.
furnace repair

Shane F.
cleaning
Will L.
clean and safety check on a Jerry Kelly emerald 90 percent efficient furnace with a humidifier #runninggreat

Matt H.
Just installed another new Jerry Kelly Emerald high efficiency furnace and ac.
Shaun M.
Repairing a malfunctioning air conditioner.
Shaun M.
Repairing a malfunctioning air conditioner.
Jeff T.
gas furnace
Jeff T.
furnace check
Steve L.
heat tune up
Jeff T.
no cooling
Will L.
tuning up a Jerry Kelly 90 percent efficient furnace to keep it running at its best #cleanandcheck#heatson
Jeff T.
electric furnace tuneup
Ronan w.
furnace cleaning

John W.
furnace tune up
Ronan w.
furnace maintenance

Shane F.
cleaning

Shane F.
cleaning
Mike S.
emerald gas furnace tune up

Shane F.
cleaning

Shane F.
cleaning