Is your furnace blowing cold air instead of heat? You deserve to stay warm. Call us today at (314) 471-7625 or visit our contact form.
There’s nothing more frustrating than cranking up the heat on a chilly St. Louis day only to feel cold air blowing from your vents. If your furnace is blowing cold air instead of the cozy warmth you expect, don’t panic. This is a common issue with several potential causes—some of which you can address yourself and others that may require a professional HVAC technician.
Need help now? Contact us today or call us to schedule same-day service.
Nick was great! He came right out and was able to solve the problem fairly easily. He communicated well and helped us prevent a future problem as well.
Response from the owner:Thank you for the review, Philip! We are happy to hear you had a pleasant experience working with us.
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.
They have never failed to fix my hvac problems. These folks are top tier.
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!
Giovanni was very professional, helpful, patient and helped me figure out the issue, if it was covered under warranty, and next steps. Great overall experience and much appreciated.
Response from the owner:Thank you, Amy! We're glad to hear that Giovanni provided you with such professional and helpful service. Your appreciation means a lot to us!
Always professional and thorough whenever they service our home. We have used Thomas Hoffmann Air Conditioning & Heating multiple times since we moved into our home and will continue to use them in the future.
Response from the owner:Thank you for the thoughtful review, Joe. We appreciate you and your business!
0 stars if I could. Bought a faulty (not to mention overpriced) surface igniter, called back five minutes later after installing, of course they didn’t stand behind their part. Go to Grainger instead. Same (working) part, half the price.
Response from the owner:Hi there. I am unable to locate your customer profile. Please give our office a call at 314-471-7625 so we can get this figured out for you.
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.
My furnace was not working. A very nice gentleman came out this morning and fixed the problem and now I have much needed heat. He was very professional and courteous. I will definitely be using them again when the need arises.
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!
I will always call Hoffmans for my air and heat needs. They were out to my daughters house that day and fixed it. It was right before the weekend storm with below zero temps the next day. They saved my daughter and grandbabies. I could never thank them more.
Response from the owner:We are so happy to hear that we could help! Thank you for the kind review.
Snow and drifting snow covered intake and out take vents causing the furnace emergency to shut off furnace. Cleaned off the driftibg/ snow off roof and vents furnace works perfect now. Thank you and great job Nick.
Response from the owner:Thanks for the great review, Scott! We appreciate your support.
5 stars! Nick was here to fix my heater within 2 hours of my call. He explained the problem to me thoroughly and got the job done quickly & professionally. Thank you so much!
Response from the owner:Thank you for the kind review, Jennifer! Glad we could help.
Extremely thorough and educational. They do a wonderful job of explaining everything and making sure I was comfortable knowing how the systems worked in my house!
Response from the owner:Thanks for the great review, Matthew! We appreciate your support.
I noticed a strange noise that I was concerned was linked to my furnace. I called Thomas Hoffman Heating & Cooling and Nick came right out. He was very thorough checking all components. Thankfully all checked out for us this visit. Definitely recommend Thomas Hoffman Heating & Cooling!
Response from the owner:Thank you so much for the kind review, Abby! We appreciate your business and look forward to servicing you in the future.
Thomas Hoffman is a wonderful company to work with. Techs are knowledgeable, personable & efficient.
Response from the owner:Thank you, Christine, for your kind words about our team; we appreciate your feedback and are glad to hear you had a positive experience!
Got a quote over the phone. Everything was explained thoroughly. Dakota, my technician arrived and on time, was very professional and knowledgeable. He didn’t try to upsell or change anything. He did a great job. We can already tell the difference since the ducts and vents were cleaned. Would recommend an use Hoffman again in the future.
Response from the owner:Happy to hear you had a pleasant experience using Thomas Hoffmann!
The technician, Ryan, was knowledgeable and helpful in identifying the issue with our mini split AC unit. They are the second company we called after issues with the first and will be using Hoffmann again.
Response from the owner:We are so happy to hear your experience with Thomas Hoffmann was pleasant. Thank you for your kind review, & we look forward to working with you in the future!
woke up to a very cold house, called Thomas Hoffmann, they were able to come out a couple of hours later and get the issue resolved. Always trust them, they have always been quick to respond and get either the heating or ac issue fixed that day. Also a great price!!!! give them 10 stars if i could, Thank You JS
Response from the owner:Thank you for the kind review, Jim. We are happy to hear that you had a positive experience working with Thomas Hoffmann!
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!
The technician Giovanni was excellent and on time very professional and efficient and knowledgeable of the project at hand ,gave great advice but most of all did great work 👏 thank you .
Response from the owner:We are so happy to hear you had a great experience, Sam! Thank you for the review, and thank you for your business.
Your service technician was very professional and knowledgeable. And did not appear to try to give me bogus information. I truly appreciate his honesty because several other companies did not appear to be honest, obviously wasn’t honest, my gut feeling told me they were not honest and tried to get me to spend $10,000 for a problem that was much simpler to fix. I look forward to you servicing all my properties, and possibly those of the rest of my family.
Response from the owner:Thank you so much for the kind words and great review! We appreciate your support.
Your Thermostat Is Set Incorrectly
Before examining furnace components, check the thermostat. It may sound simple, but settings can be accidentally changed.
Ensure it’s set to “Heat” and not just “Fan.”
If the fan is set to “On,” it will blow air continuously, even when the furnace isn’t actively heating. Set it to “Auto” so it only runs when heating.
Quick Fix: Adjust your settings and give the system a few minutes to respond.
The Furnace Hasn’t Warmed Up Yet
Sometimes, the furnace just needs a few minutes to get going.
It might blow cool air when it starts while the heat exchanger warms up.
Quick Fix: Wait 2–5 minutes to see if warm air starts flowing.
Pilot Light or Ignition System Issues
It may have gone out if you have an older furnace with a pilot light. Newer models use electronic ignition systems, which can also fail.
Pilot light out? Try relighting it, following your manufacturer’s instructions.
If ignition fails repeatedly, it could be due to a faulty igniter, flame sensor, or thermocouple.
Call a Pro: A certified technician can safely inspect and repair ignition components.
Dirty or Clogged Air Filter
A clogged air filter restricts airflow, causing the furnace to overheat and shut off the burner as a safety precaution. This can result in the system blowing cold air.
Quick Fix: Replace your furnace filter. A clean filter improves airflow, efficiency, and indoor air quality.
Overheating or Limit Switch Malfunction
Your furnace has a built-in limit switch to prevent overheating. If the furnace gets too hot, the limit switch will shut off the burner, but the blower may continue running, pushing out cold air.
Dirty filters, closed vents, or blocked ducts can cause overheating.
A faulty limit switch can also trigger this issue.
Call a Pro: An HVAC technician can test components, check for airflow issues, and reset or replace the switch.
Leaky Ductwork
Damaged or disconnected ducts can allow warm air to escape into unheated spaces like your attic or crawlspace, making the air from your vents feel cooler.
What to Do: Inspect visible ducts for gaps, disconnected joints, or insulation issues. Sealing or repairing ductwork often requires professional attention for hard-to-reach areas.
Furnace Is the Wrong Size
If your furnace is too large or small for your home, it may not heat efficiently or consistently.
An oversized furnace can short-cycle, turning on and off too quickly to distribute warm air.
An undersized furnace may not be powerful enough to heat the entire home.
Call a Pro: A load calculation by a local HVAC expert can help determine whether your current furnace is sized correctly for your home.
Fuel Supply Issues
Whether your furnace runs on natural gas, propane, or oil, insufficient fuel can prevent it from producing heat.
Check that your fuel supply is turned on.
If you’ve recently had service, ensure the gas valve is turned back on.
Safety Tip: If you smell gas, leave the area immediately and call your gas provider and HVAC company.
When to Call a Local HVAC Pro
If you’ve tried basic troubleshooting and your furnace is still blowing cold air, it’s time to call in the experts. At Thomas Hoffmann Air Conditioning & Heating, we offer fast, reliable furnace repair throughout St. Louis and the surrounding areas. Our technicians are trained to diagnose and fix all makes and models of heating systems.
Whether it’s a worn-out igniter, a thermostat calibration issue, or an airflow problem, we’ll get your heat back up and running—and keep your family comfortable all winter.
Need help now? Contact us today or call us to schedule same-day service.
Stay warm, stay safe, and don’t let your furnace leave you out in the cold!
