Locally Owned · Serving O’Fallon & St. Charles County

HVAC Repair & Services in O’Fallon, MO

O’Fallon has grown into one of Missouri’s largest cities, and the furnaces and air conditioners installed during that building boom are aging right on schedule. Thomas Hoffmann, Master HVAC Engineer with 30+ years in the St. Louis metro, leads the team that keeps those systems running: honest repairs, careful replacements, and maintenance that earns its keep.

4.9 Google Reviews
30+ yrs experience
24/7 phones answered

Schedule Service in O’Fallon

Describe the problem in a sentence or two and we’ll handle the rest. Business-hours calls come back within 30 minutes, and same-day visits are booked whenever openings allow.


Gas furnace repair and replacement for O'Fallon, MO homes, Thomas Hoffmann Air Conditioning & Heating

The Boom-Era Furnace Problem

O’Fallon Grew Fast. Its Furnaces Are Aging Fast, Too.

Thousands of O’Fallon homes went up in the 90s and 2000s, and many still run the builder-grade furnaces and air conditioners installed on day one. Equipment like that often starts showing its age around the 15-to-20-year mark: ignition trouble, short cycling, rising bills. This is where 30+ years of hands-on diagnosis pays off. We tell you honestly whether the system has more good winters in it, and when it doesn’t, we put a repair price and a replacement quote side by side so the decision is yours.

Local

St. Louis Based

An independent local company serving St. Charles County, not a franchise wearing a familiar-sounding name.

30+

Every Kind of System

Three decades on gas, electric, and dual-fuel equipment, from original builder installs to today’s high-efficiency units.

Upfront

Clear Estimates

Pricing in writing before any work begins, so the bill at the end matches the number at the start.

24/7

Breakdowns Don’t Wait

Live dispatch around the clock, because equipment fails on holiday weekends more often than it should.

Urgent? Call Now.

Furnace out on a school morning? AC dead in a heat wave?

Call at any hour and a live dispatcher sorts the true emergencies from the can-wait-until-morning problems, then gets a technician headed to O’Fallon. And the rule that overrides everything: if you smell gas or a carbon monoxide alarm sounds, get everyone out of the house first and call from outside.

24/7 Emergency HVAC Service in O’Fallon Live answer, honest triage, fast dispatch.
Call (314) 471-7625

Straight From Customers

4.9 ★ on Google, One Honest Job at a Time.

goostorm
1 day ago
Quick service, solved the problem. Thanks!
James H.
2 days ago
The repairman arrived at around 8:30 AM and spent about three hours working on the unit, which I purchased from them less than a year ago. At the end of three hours, he informed me that my unit was not working because I had the wrong filter in it. I raised a question about why it took three hours to replace the filter. I can't really explain his response because it was in technical jargon that I did not understand well enough to know what other questions to ask. The unit has a two year parts and labor warranty and a 10 year manufacturer parts warranty. unfortunately, I did not get the benefits of those warranties because, as the technician put it, the onus for using a less effective filter, rests with the customers. Then, he went on to describe to me the best filter choice, something the average customer would not automatically know. My greatest disappointment was being denied the benefits of my warranties. On the plus side, once management became aware of my dissatisfaction, they reached out to me with an apology for any role they played in my dissatisfaction and, as a show of their good intentions, they shredded my check, subsequently, not charging me for their service. This response showed a genuine commitment to quality and efficient service, as well as a commitment to customer satisfaction. Consequently, I highly recommend Hoffmann Air Conditioning services.
Response from the owner:Thank you, James, for your 5-star rating; we truly appreciate your support!
KATIE DOOLEY C.
3 days ago
I was distraught to find out our 20 year old HVAC needed to be replaced. Hoffman was beyond empathetic and took care of me within 24 hours during the heat wave. They were on time and very efficient. I have to have trust worthy people work on our house and be in our cocoon, therefore Hoffman has always been our contractor and always will be! They have become family;) I refer all of my clients to them!!!
Tiffany B.
6 days ago
My experience was very pleasant. Nick was great got my problem taken care of. He explained how to use my new equipment . Thank you for a true 24 hr service.
Response from the owner:Tiffany, thank you for the 5-star review. We appreciate you and your business!
Kathleen J.
1 week ago
Very prompt, conscientious and personable. Work well done.
Response from the owner:Thank you, Kathleen! We appreciate your kind words about our team's promptness and attention to detail. Your feedback means a lot to us!
Lisa O.
1 week ago
The tech was great. He showed up on time, was very polite, answered all my questions and got the job done. The service was also very reasonably priced.
Response from the owner:Thank you, Lisa! We're glad to hear you had a great experience with our technician. Your feedback about punctuality, politeness, and value is much appreciated!
Bill G.
1 week ago
Technician, Giovanni Leone, did such a great job in fixing our AC on a Saturday morning when the Temp is supposed to get up to 100 degrees, later today! I felt like we were in excellent hands and he explained everything he was going to do and then explained in even greater detail once everything was done! I told him if he ever wants to go into sales, he should! He has great personable skills! We have used Thomas Hoffmann before for our heating and cooling needs and they are always professional and trustworthy! My only mistake was not having them to come out to check our AC in the past 3 years!
Response from the owner:Thank you, Bill! We're so glad to hear about your positive experience with Giovanni. It's great to know that you felt well taken care of and appreciated his thorough explanations. We truly value your trust in us for your heating and cooling needs, and we look forward to serving you again in the future!
Robinette H.
3 weeks ago
He came early and identified the problem ordered the part and put it in. He was professional, neat in appearance. I would say an asset to your company.
Response from the owner:Thank you, Robinette! We appreciate your kind words about the professionalism and neatness you experienced. It's great to hear that our team member made a positive impact. Your feedback means a lot to us!
Susan H.
3 weeks ago
Very professional and polite. Did a great job.
Response from the owner:Thank you, Susan! We appreciate your kind words and are glad to hear you had a great experience with our team.
Ted E.
3 weeks ago
Nick came by, identified the problem quickly and had it fixed. Great service!
Response from the owner:Thank you, Ted! We're glad to hear that Nick provided you with quick and effective service. Your feedback is greatly appreciated!
William H.
3 weeks ago
Zach was great. He helped me better understand my systems and their operating systems.
Response from the owner:Thank you for the 5-star review, William. We are happy to hear Zach took good care of you.
Kaliyah
3 weeks ago
Quality service, fast, very professional!
Response from the owner:Thank you, Kaliyah! We're glad you experienced our quality service and professionalism. Your feedback means a lot to us!
Jacob K.
3 weeks ago
The technician that came to my house was awesome. He explained the issue and was 100% honest with me. He worked with my wishes and did a great job! Thank you
Response from the owner:Thank you, Jacob! We're glad to hear that the technician provided excellent service and was honest with you. Your feedback is much appreciated!
Lucas S.
3 weeks ago
Quick response, professional service. Made it out made the repair even on a holiday.
Response from the owner:Thank you, Lucas! We're glad to hear you appreciated the quick response and professional service, especially during the holiday. Your satisfaction means a lot to us!
Beth G.
3 weeks ago
Zach came out quickly and fixed our A/C on the 4th. He was pleasant and super efficient! A/C fixed and he was out of here, made our day for sure! Plus he likes dogs!
Response from the owner:Thank you, Beth! We're glad to hear that Zach was able to fix your A/C quickly and efficiently, and it's great to know he made your day better. We appreciate your kind words!
Rich J.
4 weeks ago
Excellent customer service and Repair work
Response from the owner:Thank you, Rich! We're glad to hear you had an excellent experience with our customer service and repair work. Your feedback means a lot to us!
Jennifer H.
4 weeks ago
Nick was fantastic. He was a great communicator, efficient and educated me and let me take the drivers seat to decision making without feeling pushed. I will for sure recommend friends and family. Service like this doesn’t come around much these days.
Response from the owner:Thank you, Jennifer! We're glad to hear that Nick provided you with excellent service and made you feel empowered during the process. We appreciate your recommendations and look forward to serving you and your friends and family in the future!
Michael G.
4 weeks ago
Extremely responsive and high quality work.
Response from the owner:Thank you, Michael! We appreciate your kind words about our responsiveness and quality of work.
Elizabeth K.
4 weeks ago
Tom was prompt, courteous and got the AC running right away. I will call him again with any needs.
Response from the owner:Thank you, Elizabeth! We're glad to hear that Tom provided prompt and courteous service. We appreciate your trust and look forward to assisting you again in the future!
Erin B.
4 weeks ago
This is the 2nd time we have used this company for our hvac needs. Great company, fast response, tons of communication and they find the problem and fix immediately. Even during the very hot weather. Couldn't recommend them enough.
Response from the owner:Thank you so much for the kind review, Erin. We appreciate your continued support!
Rich C.
1 month ago
Very prompt response and very professional and conscientious repair service. Nick did a great job and is a very nice guy.
Response from the owner:Thank you, Rich! We're glad to hear you had a great experience with our repair service. Nick will be pleased to know his efforts made a positive impression. We appreciate your feedback!
Becky W.
1 month ago
I called on a Monday morning as air conditioning was blowing warm air. They were able to come to my house very early afternoon and fixed the problem. Would highly recommend and will use them again.
Response from the owner:Becky thank you so much for your great review. We appreciate your business and your kind words.
tori M.
1 month ago
Arrived quickly and fixed our AC issue with ease!
Response from the owner:Thank you, Tori! We're glad to hear that we could quickly resolve your AC issue. Your satisfaction means a lot to us!
James H.
1 month ago
Came out immediately after a time slot opened and fixed the AC issue.
Response from the owner:Thank you, James, for your kind words! We're glad we could address your AC issue promptly.
dawn B.
1 month ago
Had new hot water heater put in. Zack was great. On time and neat
Response from the owner:Thank you, Dawn! We're glad to hear that Zack provided great service and was punctual and tidy during the installation of your new hot water heater. We appreciate your feedback!

Common Questions

O’Fallon HVAC Questions, Answered Without the Runaround

Do you offer emergency HVAC service in O’Fallon?

Yes, 24/7 including weekends and holidays. Call (314) 471-7625 and a live dispatcher will gauge the urgency and get a technician assigned as quickly as the schedule allows.

Do you cover all of O’Fallon’s neighborhoods?

Yes. From WingHaven and Twin Chimneys to the established streets near Highway K and Mexico Road, we work across the whole city, in newer builds and older properties alike.

My furnace keeps turning on and off. What does that mean?

Short cycling can have simple causes, like a clogged filter, or bigger ones, like an overheating heat exchanger, a failing sensor, or an oversized system. It’s worth diagnosing promptly because it drives up bills and wears parts faster. We find the actual cause before recommending anything.

Do you handle ventilation and indoor air quality?

Yes. Newer, tightly sealed O’Fallon homes often trap stale air, humidity, and allergens. We assess ventilation and can add filtration, humidity control, or fresh-air solutions matched to the house and the family living in it.

Should I replace my furnace and AC at the same time?

Often it makes sense when both are similar in age, since matched systems tend to run more efficiently and installation costs overlap. But it isn’t automatic. If one unit has real life left, we’ll say so and price the options separately so you can compare.

Which communities near O’Fallon do you serve?

Lake St. Louis, Dardenne Prairie, St. Peters, Cottleville, Wentzville, St. Charles, and the rest of the St. Louis metro.

O’Fallon Comfort, Handled by People Who Answer.

One locally owned company, 30+ years of St. Louis HVAC experience, estimates in writing, and a phone answered at every hour of every day.