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.

Thomas E.
1 day ago
Very fast response and professional service.
Kay H.
2 days ago
Zach came around 9:00 the early part of my window. It was my annual checkup and he said everything looked good. I will be moving out of state soon but appreciate your past service.
Response from the owner:Thank you so much for the great review, Kay. We truly appreciate your business!
William H.
3 days 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.
Thomas E.
3 days ago
They installed our system and came out to check on a concern promptly and didn’t charge us.
Pat Keith T.
4 days ago
Zachary is great! We purchase Hoffmans maintenance plan - they come when needed
Response from the owner:Thank you, Pat, for your kind words about Giovanni; we appreciate your feedback and are glad to hear that he made a positive impression.
Beth R.
5 days ago
Competence and knowledge have been my experience.
Response from the owner:Thank you, Beth, for sharing your experience; it means a lot to us!
Becky W.
6 days 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.
Frank P.
7 days ago
From the phone to the completion of the job everyone is so polite and informative. I had Giovani as our representative and he was very informative and professional, and knew exactly what the problem was. Thanks so much.
Response from the owner:Thank you for the kind review, Frank! We appreciate you and your business.
Adi S.
2 weeks ago
Our AC condenser and coil were swapped out. The company did a very good job with staff that were most professional. Would happily recommend their company and keep them for all my annual maintenance work. I stress their staff is very knowledgeable and professional.
Response from the owner:Thank you, Adi! We're glad to hear you had a positive experience with our team and appreciate your recommendation. Your kind words about our knowledgeable and professional staff mean a lot to us.
Chris S.
3 weeks ago
great people
Response from the owner:Thank you, Chris! We appreciate your kind words about our team.
Christine M.
3 weeks ago
Needed help after hours and they called me back right away! Super helpful and were able to fit me in when I was in a bind during the STL heat wave.
Response from the owner:Thank you, Christine! We're glad we could assist you promptly during the heat wave. Your satisfaction is our priority, and we appreciate your kind words!
ruter
3 weeks ago
Exceptional Service from Start to Finish!I recently hired Thomas Hoffmann Air Conditioning & Heating to replace my complete HVAC system, and I could not be happier with the experience. The installation crew—Zachary and Giovani—was absolutely top-notch. They were professional, courteous, and incredibly meticulous with their work
Response from the owner:Thank you, Ruter! We're so glad to hear you had an exceptional experience with our team, and we'll definitely pass on your kind words to Zachary and Giovani. Your satisfaction means a lot to us!
Richard H.
3 weeks ago
Great people & work
Response from the owner:Thank you, Richard! We appreciate your kind words about our team and the work we do. Your support means a lot to us!
Joe B.
3 weeks ago
Thomas Hoffman Air Conditioning and Heating did a fantastic Job for my company. They promptly responded to an emergency situation that occurred over a holiday weekend. They expedited the delivery of replacement parts Free piece of equipment that had broken down, and installed it immediately after receiving it. They were prompt, professional, and friendly. I would highly recommend them to anyone in need of HVAC services.
Response from the owner:Thank you, Joe! We appreciate your kind words about our team's promptness and professionalism, especially during an emergency. It's great to know that Thomas Hoffman Air Conditioning and Heating met your needs so effectively. Your recommendation means a lot to us!
Alex C.
3 weeks ago
Nick was at my house in Kirkwood within hours of my call and was able to get me back up and running on a super hot day. Very pleased with the service and will be calling them for my HVAC needs in the future.
Response from the owner:Thank you, Alex! We're glad to hear that Nick provided prompt and effective service, especially on such a hot day. We look forward to assisting you with your HVAC needs in the future!
Theresa S.
3 weeks ago
Very punctual. Answers all my questions and concerns. Already scheduled for next service!
Response from the owner:Thank you, Theresa! We're glad to hear you appreciate having the same technician and the communication about your units. Your feedback on our customer service means a lot to us!
Lynn C.
3 weeks ago
Thomas was great! He arrived on time and fixed my problem quickly. I live in Clayton. I highly recommend Thomas Hoffmann Air Conditioning and Heating!
Response from the owner:Thank you, Lynn! We're glad to hear that Thomas provided prompt and effective service. Your recommendation means a lot to us!
steve B.
3 weeks ago
Fantastic service and friendly. We had an AC unit issue and they responded quickly and made the required repairs.
Response from the owner:Thank you, Steve! We're glad to hear you had a great experience with our service and that we could assist you promptly with your AC unit issue. Your feedback means a lot to us!
Matthew John D.
4 weeks ago
The truth of their proffesionalism forces you to Trust their expertise and a determined focus on customer satisfaction was unfortunately a rare experience in my years of east coast building maintenance.
Response from the owner:Thank you, Matthew, for recognizing our professionalism and commitment to customer satisfaction. We're glad to hear that your experience stood out after your years in building maintenance. Your support means a lot to us!
Kevin E.
4 weeks ago
Nick demostrated excllent customer service,professionalism, and technician.
Response from the owner:Thank you, Kevin! We're glad to hear that Nick provided excellent customer service and professionalism. Your feedback is greatly appreciated!
George B.
4 weeks ago
We live in Dardenne Prairie, and want to thank Tom for his excellent work in assessing our A/C unit that stopped working over Labor Day weekend where the outdoor temps were 100+. Tom not only had the exact components on-hand but also offered other future solutions to make our home more comfortable. Very personable and professional! Thanks Tom!
Response from the owner:Thank you, George! We appreciate your kind words and are glad to hear that Tom provided excellent service during such a hot weekend. Your satisfaction is important to us, and we're here to help with any future needs!
Katherine G.
4 weeks ago
Nick came out to our house in Valley Park. Super nice and helpful. Got our AC back to running!
Response from the owner:Thank you, Katherine! We're glad to hear that Nick was able to help get your AC running again. Your satisfaction is important to us!
ladodger6
4 weeks ago
Nick is a very knowledgeable HVAC professional. He quickly and thoroughly inspected my system. Highly recommend Thomas Hoffman AC.
Response from the owner:Thank you! We appreciate your kind words about Nick and are glad to hear you had a positive experience with Thomas Hoffman AC. Your recommendation means a lot to us!
Louise P.
4 weeks ago
My air conditioner went out, my son called, Nick was able to come out same day, very pleasant and professional.
Response from the owner:Thank you, Louise! We're glad to hear that Nick was able to assist you promptly and provide a pleasant experience. We appreciate your kind words!
Chris
4 weeks ago
Saturday. Labor Day Weekend. 100 degrees for the 4th day in a row and counting. A.C. goes out. No hvac companies well return calls and their phonebots say they're not available until Tuesday or Wednesday. Nick with Hoffmann answer's first ring and shows up in a couple hours, make short work of it, house is cooling nicely. Thanks Nick and Company.
Response from the owner:Thanks, Chris! We're glad Nick was able to help you out quickly, especially during such a hot weekend. We appreciate your feedback and are here for any future needs.

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.