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.

Hank K.
15 hours ago
Fast, friendly, professional service.
Response from the owner:Thank you, Hank, for your wonderful feedback; we're glad you enjoyed the fast, friendly, and professional service, and we'll be sure to keep up the great work!
Jack R.
2 days ago
Our tech was scheduled to arrive to our house in Brentwood only a few hours after I called. Nick was great and was able to address the issue quickly. Thanks again!
Response from the owner:Thank you, Jack! We're glad to hear that Nick was able to resolve the issue quickly for you. Your satisfaction means a lot to us!
Melanie L.
2 days ago
Nick was amazing!!! He came out after hours to my home in Creve Coeur when my AC stopped working. He was professional, knowledgeable, and genuinely helpful. I really appreciate him going above and beyond when I needed help. Highly recommend!
Response from the owner:Thank you, Melanie! We’re glad to hear that Nick provided such excellent service and went above and beyond for you. Your recommendation means a lot to us!
Margaret K.
3 days ago
Clear communication about arrival, service and costs.
Response from the owner:Thank you, Margaret, for your kind words! We appreciate your feedback on our clear communication and are glad you had a positive experience.
Rich C.
3 days ago
Very prompt response and very professional and conscientious repair service. Nick did a great job and is a very nice guy. I apparently have an intermittent problem that did not occur today. Your technician was excellent and system is now working, so I will call if issue recurs. You have terrific associates.
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!
Ryan B.
3 days ago
I called on a hot summer day and they came out and had it fixed super fast!
Response from the owner:Thank you, Ryan! We appreciate your kind words and are glad to hear we could help you quickly on that hot day.
david W.
3 days ago
Amazing response time and service for AC replacement! Our AC failed on Monday evening, Nick came out to inspect and give us options within the hour, and we had a new AC installed by 1pm on Tuesday. Great team and very happy
Response from the owner:Thank you, David! We're glad to hear about your positive experience with our team, especially with Nick's quick response and the timely installation. Your satisfaction means a lot to us!
Lori B.
4 days ago
I can’t say enough wonderful things about Thomas Hoffmann Air Conditioning and Heating! Nick came promptly, which was such a relief, and from the very beginning, he was personable, professional, and incredibly honest. After dealing with other companies, Nick’s honesty really stood out. He took the time to explain everything clearly, answer my questions, and make sure I understood what was going on—without any pressure or unnecessary recommendations. It was refreshing to feel like I was dealing with someone who genuinely cared about doing the right thing for the customer. Nick’s professionalism, knowledge, and customer service were truly top-notch. I wouldn’t hesitate to recommend Thomas Hoffmann Air Conditioning and Heating to anyone looking for a heating and cooling company you can actually trust!
Response from the owner:Thank you for the 5-star rating, Lori!
Connor L.
4 days ago
Very responsive and helped us promptly on one of the hottest nights in the summer!!
Response from the owner:Thank you, Connor! We're glad we could assist you quickly during such a hot night. Your feedback means a lot to us!
Logan L.
4 days ago
So professional and came within 10 minutes of our emergency! Nick was 10/10!!!
Response from the owner:Thank you, Logan! We're glad to hear that our team responded quickly and that Nick made such a positive impression. Your feedback means a lot to us!
John P.
1 week ago
They did great work on a tight timeline. They saved our business that day! Very professional and smart. I will use them every time!
Response from the owner:Thank you, John! We appreciate your kind words and are glad we could help your business on such a tight timeline. Looking forward to working with you again!
Morgan T.
1 week ago
The service was excellent! When we arrived home after 8 pm, seen our unit was not working and it was almost 85 degrees in our home my husband began calling all of the companies that said they were 24 hrs. Thomas Hoffman heating and cooling was the only company that honored the statement. Nick was at our home in a very timely manor and was also able to fix our unit quickly! I would highly recommend to anyone needing any hvac services!
Response from the owner:Thank you, Morgan! We're glad to hear that you had an excellent experience with our service. It's great to know that Nick was able to assist you promptly and effectively. We appreciate your recommendation and look forward to helping you again in the future!
Excellent service and a job very well done. Highly recommended!
Response from the owner:Neil, thank you so much for the great review. We appreciate your continued support and business!
Timothy L.
1 week ago
Tom was amazing and fast , came out for a 24 hour service call and did quick work to keep us in our home during a summer heatwave.
Response from the owner:Thank you, Tim! We're glad to hear that Tom provided amazing and quick service. Your comfort is important to us!
Margaret F.
2 weeks ago
Excellent service, on time, professional!
Response from the owner:Thank you, Margaret! We appreciate your kind words and will make sure to pass along your praise to Nick for his excellent service.
lisa D.
2 weeks ago
Thomas Hoffman HVAC provides excellent service. The staff members are very nice, respectful and knowledgeable. I always feel comfortable with the advice I have been and the fees for repairs. Whether we see one of the companies employees or Thomas himself we have always had a good experience and highly recommend them. I am thankful to have found a trustworthy company to count on for my future needs.
Response from the owner:Thank you for the 5-star review, Lisa. We appreciate the support!
Michael M.
3 weeks ago
Everything went very well , excellent service, our AC should be good now .
Response from the owner:We are happy to hear it, Mike! Thanks for the 5-star review.
jane G.
3 weeks ago
Nick did an outstanding job on checking the attic and replacing damaged insulation. He showed me where the leak was coming in from the roof. Excellent overall job
Response from the owner:Thank you, Jane! We're glad to hear that Nick provided exceptional service by checking the attic and addressing the insulation issue. Your satisfaction is important to us!
Tom C.
3 weeks ago
Nick is very professional and have our AC issue resolved within an hour.
Response from the owner:Tom, we are so happy to hear you enjoyed working with Nick. We appreciate the great review and your business!
KATIE DOOLEY C.
4 weeks 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!!!
Response from the owner:Thank you, Katie! We're so glad to hear that you felt supported during a tough time. Your trust means the world to us, and it's wonderful to know that we’ve become part of your family. We appreciate your referrals and look forward to continuing to serve you and your clients!
Becky W.
4 weeks 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.
Spencer W.
1 month ago
Thomas Hoffmann provided outstanding service from start to finish. The technician was professional, knowledgeable, and took the time to explain everything clearly. They arrived on time(early), diagnosed the issue quickly, and had my AC running perfectly in no time. I really appreciated their honest recommendations and fair pricing—no pressure or unnecessary upselling. It's refreshing to work with a company that truly values customer service. I highly recommend Thomas Hoffmann to anyone looking for reliable, high-quality HVAC service.
Response from the owner:Spencer, thank you so much for the 5-star review. We really appreciate your kind words, & your business.
john J.
1 month ago
Got a checkup on the hottest day of the year and everything is working fine. Great service.
Response from the owner:John, thank you so much for the nice review! We are so happy to hear you had a positive experience.
Brad G.
1 month ago
Outstanding...Giovani was superb..need him as a regular for our regular maintenance!
Response from the owner:Thank you, Brad! We're glad to hear you had a great experience with Giovani. We appreciate your feedback and will certainly keep your request in mind for your regular maintenance.
Jennifer H.
1 month ago
Service Technician was very nice and friendly.
Response from the owner:Thank you so much for the amazing review, Jennifer. We truly appreciate it!

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.