At Thomas Hoffmann Air Conditioning & Heating, we’ve seen it all. Contact us today by calling (314) 471-7625 or using our contact form.
There’s nothing worse than waking up on a cold Missouri morning, cranking up the thermostat, and feeling cold air blowing from your vents. If your furnace is supposed to be keeping your home warm and cozy, but instead it’s acting like an AC unit, don’t panic—several common causes could explain the issue, many of which are quick to fix.
Fast efficient service. Both of the gentlemen that came to my home were very help and informative not to mention polite. It’s difficult to get service advisers to appear at your home when scheduled most times they’re late or don’t show up at all. Not an issue with this team on time, clear diagnosis, quick repair. I would definitely use Thomas Hoffmann Air Conditioning again. I recommend them highly.
First visit for my maintenance program. Arrived on time. Very polite to talk to. They discussed what they did and everything was good. They were professional. I would recommend this company to everyone.
Response from the owner:We're delighted to hear about your positive first visit experience with us! Thank you for recommending our services.
Very knowledgeable. Very professional. Tom was very thorough and finally confirmed the issues in the system that no one else bothered to check.
Response from the owner:Thank you, David, for your kind words; it's great to hear that Tom's thoroughness made a difference in addressing the issues in the system. We look forward to working with you in the future!
I’ve been using “THOMAS Hoffmann Airconditioning and Heating” for years now. We have a 30 +\- year old system that works perfectly for us. Although we’ve not had to use it yet, it is comforting to know they offer a 24 hour on call service. I really appreciate that the technicians don’t try to upsell us on anything. They’re a very professional, knowledgeable, and courteous, local-family owned and operated business. I’ve also found their pricing to be very fair and by”fair” I don’t mean “cheap” but reasonable… especially for the quality of service provided by THOMAS Hoffmann HVAC. I love supporting smaller family owned business and this one is top-notch! Thank you guys!
Response from the owner:Thank you so much for your continued support and kind words, Mari! We truly appreciate your loyalty and are glad to hear about your positive experiences with our services. We look forward to continuing to provide you with top-notch service in the future.
Great customer service & experience for our HVAC System! They installed two UV lights and a dehumidifier. On time, great service, the new items work great - Great HVAC Service in St. Louis! Thank you!
Response from the owner:Thank you, Brandon, for your wonderful feedback! We're glad to hear that you had a great experience with your installations Your satisfaction is our priority!
Thank you Thomas Hoffman Air Conditioning for doing a great of repairing our HVAC system that was damaged during a power outage. You installed our new HVAC system late last year and promptly responded to our call for repair after a power surge impacted our subdivision.
Response from the owner:Thank you, Don, for your kind words! We're glad to hear that Thomas Hoffman Air Conditioning was able to assist you so quickly after the power surge and that you're satisfied with your new HVAC system. Your support means a lot to us!
This company is so responsive that I love them. They respond immediately, and I trust them to tell me what needs to be done. I haven’t been steered wrong yet. They are genuinely nice to work with and honest. I use their maintenance program which I highly recommend.
Response from the owner:Thank you for your kind words, we truly appreciate your trust in us and are glad to hear about your positive experience with our services.
Quick response and did a great job. On a Saturday.
Response from the owner:Thank you, Scott! We're glad to hear you appreciated the quick response and great service, especially on a Saturday. We look forward to continue serving you.
As owner of rental and living out of town, it is very easy and painless to have Thomas Hoffman schedule all of my seasonal work with the tenant. Highly recommend!
Response from the owner:Thank you for trusting us with your rental property maintenance, Dan! We appreciate your recommendation!
Just had our annual service on our A/C. The technician, Giovanni, was very professional, friendly, thorough and spent time explaining what all he did and what his findings were. Couldn't be happier. I HIGHLY RECOMMEND THOMAS HOFFMAN AIR CONDITIONING AND HEATING.
Response from the owner:Terry, we're so grateful for your kind words and for recommending us! We're thrilled to hear that you had a positive experience with our technician during your annual furnace service. Thank you for choosing Thomas Hoffman Air Conditioning and Heating!
I called on December 25th at midnight and started leaving a message and Thomas Hoffman the owner called me back almost immediately. He said he would come out the next morning between 8:00 and 10:00 am snd he was promptly on time. He fixed my problem and while he was there I decided to get an estimate for a new furnace and air conditioning unit. The price was very reasonable and the installers one of them being his son were both very professional very courteous, polite, arrived on time and finished the same day. I enjoy knowing that I now have the support of Thomas Hoffman heating and air conditioning along with the peace of mind that comes with owning a Trane. Nothing stops a Trane.
Albert Koesterer
Response from the owner:Albert thanks so much for your kind reviews and your business. We truly appreciate it!!!
I made another service call years after my last review. Once again, Tom did not disappoint. He identified the cause of my newly purchased system installed by another HVAC company. He explained it so simple and easy to understand without the technical jargons. I just wished I had purchased the new equipment from Tom instead of saving a few hundred dollars from his competition.
Response from the owner:Thank you, J, for your kind words! We're glad to hear that Tom was able to assist you so effectively and make everything easy to understand. We appreciate your continued trust in our services and hope to help you again in the future!
I've used these guys twice now and their response time is great, they are friendly, informative, and most importantly, effective. I'm calling these folks every time my furnace sounds weird.
Response from the owner:Thank you for the wonderful feedback, Greg! We're glad to hear that you've had such positive experiences with our team. Providing timely and effective service is our priority, and we're here whenever you need us. Looking forward to assisting you again!
Nick was on he way to our house when I had to cancel my appointment for service. Nick was very understanding and professional about it. While we didn't get to utilize him, I have no doubt he'd have been just as professional in his job.
Response from the owner:Thank you for your kind words. We appreciate your understanding and are glad to hear that Nick made a positive impression. If you ever need our services in the future, don't hesitate to reach out.
I couldn’t be happier with Thomas Hoffman. They are quick, courteous, and super knowledgeable as well as providing service at a good value. Most importantly to me, they have great integrity. I could not recommend them more highly!
Response from the owner:Thank you for your wonderful review, Josh and Nikki! We’re thrilled to hear that you had such a positive experience with our team. Providing quick, courteous, and knowledgeable service is our priority, and we're glad to know that our efforts resonate with our customers. Your recommendation means a lot to us!
Tom was a great service technician- arrived promptly on time - and fixed our issue within a few minutes!! Very nice guy too!
Response from the owner:Thank you for the wonderful feedback! We're glad to hear that Tom provided prompt and effective service. Our team strives to deliver a great experience, and it's fantastic to know that you were satisfied. If you need any assistance in the future, don't hesitate to reach out!
Very prompt and friendly service. Will definitely call them again.
Response from the owner:Thank you for the positive feedback! We're glad to hear that you were pleased with our prompt and friendly service. We look forward to assisting you again in the future!
Tom Hoffmann has been servicing both our residential and commercial equipment for several years. Tom is an experienced, innovative engineer, he can troubleshoot and solve any problem that arises. He has even personally serviced our furnace on a holiday! The trust, communication, knowledge, and relationship we have built is why we choose Tom Hoffmann every time, and highly recommend him to all our colleagues
Response from the owner:Thank you, Dan, for your wonderful review and for highlighting Tom's dedication and expertise; we're grateful for your trust and support over the years!
This was my 1st time using Thomas Hoffmann A/C & Heating, but it will probably not be my last. After calling 📞 a few companies near my location & not getting a response, I decided to call Thomas Hoffman & someone immediately answered. I needed someone to comeout & look at the installation of a new Smart Thermostat & let me know if it was installed properly & if not, install it correctly for me. I was given a appointment on the day that I called for later that morning with a gentleman named Nick who supposedly was the guy that knew all about Thermostats & Wiring. Nick arrived & honestly saved the day. He was very personable & professional & did a very thorough job while explaining everything thoroughly. Nick is a very valuable asset to the Hoffman company & represents their company & himself with great pride. I felt like I was in safe hands, & Nick performed quality work. Thomas Hoffman is a company that U can trust & get ur money's worth if not more. I look forward to doing more business with them in the future....
Response from the owner:Thank you, Harlan, for sharing your experience with us! We're glad to hear that Nick provided such excellent service and made you feel confident in your Smart Thermostat installation. Your trust means a lot to us, and we look forward to serving you again in the future!
My family was having issues with our old water heater leaking gas so we called Thomas Hoffmann’s company to help us. Giovanni and Ryan changed our water heater and replaced it with a new one fast and efficiently. I would recommend anyone looking for efficient and reliable work to give them a call. Thank you guys again!
Response from the owner:Thank you, Michael, for your kind words! We're glad Giovanni and Ryan could assist you with your water heater replacement efficiently. Your recommendation means a lot to us!
Great service. Responsive. Well trained technicians. Honest friendly and thorough. I highly recommend Tom Hoffmann and his team.
Response from the owner:Thank you for your kind words! We appreciate your recommendation and are delighted to hear about your positive experience with our team.
Giovanni and Ryan were great! Arrived on time, polite introductions, quality work and installed a new water heater in just a few hours. We have used them multiple times now and every time, they have been great!
Response from the owner:Thank you, Laura! We're so glad to hear that Giovanni and Ryan provided you with great service and quality work; we appreciate your continued trust in us!
Nick was a great technician to work with. He accurately assessed my problem and found a solution that will help keep my unit functioning without continued problems. Great and knowledgeable company.
Response from the owner:Thank you, Amond! We're glad to hear that Nick was able to provide you with a great solution and appreciate your kind words about our company.
1. Thermostat Settings Are Incorrect or Misconfigured
Before jumping to conclusions about your furnace, always start by checking your thermostat. A simple setting issue might be the root of the problem.
What to Check:
Is the thermostat set to “ON” instead of “AUTO”? If so, the blower may run continuously—even when the furnace isn’t heating.
Is the temperature setting too low?
Are you accidentally in “cool” mode?
2. The Furnace Hasn’t Warmed Up Yet
Sometimes, it’s just a matter of patience. If your furnace just kicked on, it may take a minute or two for warm air to start circulating.
3. Dirty or Clogged Air Filter
A dirty filter can restrict airflow, cause overheating, or trigger your furnace’s safety mechanisms. This might make the system shut off the burners while the blower continues to run, resulting in cold air.
Symptoms:
Weak airflow
Increased energy bills
Furnace short cycling
4. Pilot Light or Ignition System Failure
If your furnace uses a pilot light (common in older systems) or a hot surface igniter, the burners may fail to ignite, leaving you with cold air blowing through the system.
Signs of Ignition Problems:
You hear the blower running, but no whoosh of flame
No visible flame through the inspection window
Error codes on modern control boards
5. Flame Sensor Is Dirty or Malfunctioning
Modern furnaces have a flame sensor to confirm that gas is being burned correctly. If it’s dirty or defective, it may shut down the burners to prevent unsafe operation, leaving just the fan running.
Common Symptoms:
Furnace turns on briefly, then shuts off
Cold air blows intermittently
Multiple restart attempts
6. Overheating or Limit Switch Tripped
If your furnace overheats, a safety switch (limit switch) may shut off the burners while keeping the fan running to cool the unit down. This can happen due to airflow blockages, dirty components, or mechanical failure.
7. Leaky or Disconnected Ductwork
Even if your furnace is producing heat, damaged or poorly sealed ducts can cause heat loss before the air reaches your vents, especially in unconditioned spaces like attics or crawl spaces.
Signs:
Cold air from a few vents, but not all
Uneven temperatures across rooms
Higher energy bills
8. Fuel Supply or Gas Valve Issues
If you have a gas furnace and it’s not producing heat, the gas supply may be off, or the gas valve could be faulty.
9. Your Furnace Is Reaching the End of Its Lifespan
If your furnace is more than 15–20 years old, recurring issues like cold air, uneven heating, or cycling could be signs it’s time for an upgrade.
When to Call the Experts
Some furnace problems have simple fixes, but others signal more serious mechanical issues or potential safety hazards. If you’re not comfortable troubleshooting or have tried these tips without success, call in the pros.
Thomas Hoffmann Air Conditioning & Heating offers:
Emergency heating repair across the St. Louis metro
Expert diagnostics for all major furnace brands
Transparent pricing and no-pressure service
Contact Thomas Hoffmann Air Conditioning & Heating Today
A furnace blowing cold air isn’t always a disaster—but it’s not something to ignore. With a bit of troubleshooting and the right support, you can quickly and safely restore comfort to your home.
