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.
I am very pleased with the service provided. , especially the quick response to my request . The technician came in themorning and had my cooling system repaired within an hour. Thank you !
Response from the owner:We're delighted we could promptly assist you on a Sunday morning and fix your cooling system efficiently. Thank you!
Here on time, worked fast. Always pleasant and great answering questions. Zach always does a great job.
Response from the owner:Thank you, Debra, for your kind words; we're glad to hear Zach made a positive impression and that you had a great experience with our team!
Extremely quick response for appointment and did quick fix for our furnace and heat is working great !
Response from the owner:Thank you for your kind words! We're glad to hear our team was able to respond quickly and get your furnace working great. We appreciate your feedback!
They were timely, polite, professional and they saved us from too much sweating. In a field full of pompous and arrogant technicians, these guys take the time to explain what is wrong and how they are correcting it. Other folks just assume you are incompetent but these folks take the time to educate. Cannot recommend highly enough.
Response from the owner:Thank you for your kind words! We truly appreciate your feedback and are glad we could provide you with a positive experience.
I would like to have a receipt for my payment which I did not receive. On a positive note he was very punctual very early actually he did his job and was very professional and I'm hoping and praying this took care of the issue thank you and I would not hesitate at this time to use your services
Response from the owner:Thank you, Mark, for your feedback and for highlighting the punctuality and professionalism of our team; we appreciate your support and will ensure you receive your receipt promptly.
Our experience with them was fantastic all the way through! Not only were they able to get to our business that day but the customer service from the phone call to the on-site service was professional and quick. We'll definitely be using Thomas Hoffmann Air Conditioning and Heating in the future.
Response from the owner:Thank you, Michelle, for your wonderful feedback! We're glad to hear about your fantastic experience and appreciate your kind words about our team's professionalism. We look forward to serving you again in the future!
I couldn’t be happier with the service from Thomas Hoffmann Air-Conditioning! From the moment I called, the team was professional, responsive, and truly knowledgeable. Thomas personally made sure everything was handled with great attention to detail. The installation was smooth, efficient, and the quality of the work exceeded my expectations. It’s rare to find a company that is both skilled and genuinely cares about their customers. I highly recommend Thomas Hoffmann Air-Conditioning to anyone looking for honest, reliable, and top-notch service. They’ve definitely earned a loyal customer!
Response from the owner:Thank you, Rick, for your kind words and for recognizing our team's hard work; we're grateful for your support and thrilled to have earned your loyalty!
Amazing service from Thomas Hoffmann! They made space in their schedule to come out the next day to fix our air conditioner. They were on time, honest and fixed the problem on the spot. Thank you!
Response from the owner:Thank you, Ashley! We appreciate your kind words about our team's service – it's great to hear we could help you so quickly.
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.
Response from the owner:Thank you, Anna, for your wonderful feedback! We're glad to hear that our team provided you with timely and helpful service, and we appreciate your high recommendation.
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 fixed my furnace today, excellent service, very personable and quick service on the coldest day of the year. Thank you!!
Response from the owner:Thank you, Randy, for the fantastic 5-star rating; we appreciate your support!
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.
