Cities We Serve
Austin Area:
San Antonio Area:
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Furnace Repair
Why Furnaces Here Fail on the First Cold Night
A furnace in Austin or San Antonio spends most of the year switched off in an attic that reaches 130 degrees. Dust settles on the burners and the flame sensor, the igniter gets brittle, and a pressure switch hose that was fine in February has cracked by November. Then a norther blows through, the thermostat calls for heat, and the furnace tries to light for the first time in eight months. That is why our heating calls cluster around the first few cold nights of the season, and why we run 24/7 through them.
The other thing we bring is a real diagnosis. “No heat” can be a flame sensor that takes ten minutes to clean, a failed igniter, a stuck gas valve or a cracked heat exchanger that means the furnace is done. Those are very different prices, and you should know which one you have before you spend anything. Our technician runs the furnace through its sequence, finds the part that is failing, and puts the repair in writing. Nothing happens until you approve it. If the repair is poor money on an old unit, we show you the replacement numbers next to it and let you decide.
Every repair carries the Home Comfort Guarantee, and Care Club members get 5% off with no dispatch fee.
Looking for your local team? See furnace repair in Austin or furnace repair in San Antonio.
- The sequence, not the symptom We watch the furnace try to start and test each step, so you never pay for a part that was never the problem.
- Same price after dark Upfront pricing with no surprise fees, on a Sunday night or a holiday morning.
- Home Comfort Guarantee If we cannot resolve the issue, you get a 10% inconvenience refund, up to $1,000.
What to Watch For
Signs Your Furnace Needs a Repair
One of these means shut it off and call now. The rest mean call before the next freeze.
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It clicks, tries to light, then shuts down
The classic fall failure. Usually a dirty flame sensor that cannot prove the flame, a cracked igniter, or a pressure switch that is not closing.
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The blower runs but the air is cold
The burners are not lighting or the limit switch has tripped and cut the gas. On a heat pump, it can also be a system stuck in defrost.
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Heats for a few minutes, stops, repeats
Short cycling from an overheating heat exchanger, a clogged filter, a bad limit switch or a furnace that was oversized for the house.
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Weak airflow from the registers
A blower motor or capacitor on its way out, a collapsed filter, or ductwork that has come apart in the attic.
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Banging, scraping or a loud whoosh at startup
A bang at ignition means gas is pooling before it lights. Scraping is a blower wheel. Both get more expensive the longer they run.
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A carbon monoxide alarm or a rotten-egg smell
Leave the house and call your gas utility first, then call us. Do not restart the furnace until it has been checked.
What We Repair
Gas Furnaces, Electric Furnaces and Heat Strips
One licensed technician for the burner side, the blower side and the controls between them.
- Igniters and flame sensors The two parts that fail most after a summer in the attic. We clean or replace them and confirm a stable flame before we leave.
- Pressure switches and inducer motors The draft system that has to prove the flue is clear before the gas valve will open. A cracked hose or a tired inducer stops everything.
- Gas valves and burners Valves that stick, burners that light unevenly, and the rollout and limit switches that protect you when they do.
- Blower motors and capacitors The same blower runs your AC all summer, so it is often the most worn part of the furnace by the time heating season starts.
- Control boards and thermostat wiring We read the fault codes, test the low-voltage circuit and fix the actual problem rather than swapping the board on a hunch.
- Electric heat strips and sequencers For all-electric homes: the resistance elements, sequencers and breakers inside an air handler that provide the winter heat.
How It Works
What a Furnace Repair Call Looks Like
No guessing and no pressure. You see the price before we pick up a tool.
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Tell us what it is doing
Clicking but not lighting, cold air, a smell, a tripped breaker. We book the soonest window that works, any hour of any day.
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We run the sequence
A licensed technician watches the furnace start, tests the igniter, sensor, switches and gas pressure, and inspects the heat exchanger.
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You approve the price
What failed, what fixing it involves and what it costs, in writing and honored for 72 hours. If a repair is a poor investment, we say so.
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We repair and verify
We fix it, run a full heating cycle, check the temperature rise and confirm the safety controls work before we leave.
Current Specials
Save on the work your home needs most.
No Heat Tonight?
We answer 24/7, including holidays, and the price is the same after hours.
What Our Customers Say
Don't just take our word for it — hear from our satisfied customers
★★★★★
Our 18 year old HVAC system finally gave out this past week, so we reached out to Radiant to see what could be done. They sent a tech out named Bryan the same day, and he did a great job looking over the entire HVAC system. He was friendly and helpful in explaining everything that he saw, and our options moving forward. We decided to replace the entire system, so we met with Jacob (same day thankfully) to find the best HVAC system for our needs. Jacob was friendly, professional, and did a great job explaining the different options on offer. Radiant was able to set-up next day install, which was much appreciated, because the temps were still going to be cold in the coming days.
The install team consisted of Carlos and Pablo, who were very courteous and professional, and were kind enough to answer any questions I had regarding the install. They did a great job installing our new HVAC system, and were tidy which is always appreciated! Before they left, they explained everything that had been done, and showed me photos of the work.
Our entire experience from start to finish was great. I appreciate that they send photos of who is coming to your home too. Friendly, kind, professional team members, and good work all the way around. Thanks Radiant!
The install team consisted of Carlos and Pablo, who were very courteous and professional, and were kind enough to answer any questions I had regarding the install. They did a great job installing our new HVAC system, and were tidy which is always appreciated! Before they left, they explained everything that had been done, and showed me photos of the work.
Our entire experience from start to finish was great. I appreciate that they send photos of who is coming to your home too. Friendly, kind, professional team members, and good work all the way around. Thanks Radiant!
★★★★★
This is the first time I’ve used radiant my neighbor recommended them…. I called them today and they set me up an appointment on the same day. I was totally shocked at that and the service call was only $39!!…. Highly recommend them Danielle showed up and he was a great guy and he put up with all my wishy-washiness and I had to hurry him because I was heading to church and he got caught in a lot of traffic getting here he even would’ve installed the part that broke but I Didn’t have the time tonight….. He was patient with me and just told me to call the office first thing in the morning and get a service call set up…. Thank you so much Radiant!!….
With another cold front coming in tomorrow now I just hope they can get me scheduled for a separate call tomorrow but I have a feeling they will. They are such a great company!!😊😊
With another cold front coming in tomorrow now I just hope they can get me scheduled for a separate call tomorrow but I have a feeling they will. They are such a great company!!😊😊
★★★★★
My unit had been acting funky for a bit and then decided it would shed its mortal coil and go to the next life. I called an another company lets call them company A since I had a warranty with them thinking I could save a few bucks. They showed up 2 hours late of given window. Warranty didnt cover any of the perceived issues ( not really their fault, maybe). Double billed me (why pay 700 for a service call when you can pay 1400!!! ie: they ran my card twice) and then even though issue still wasnt fixed wanted to upsell me some more for close to 3k or get another sweet unit for an overpriced amount.
I'll admit I was getting desperate. Do I let the giant commercial bad guys win? Give them all my money I could be using on fishing gear? My neighbor happens to work at Schmidt Mechanical Group (shout out to Jared) and got me in touch with their service technicians for a 2nd opinion. ENTER Richard Moreno. Showed up at the beginning of time window. Diagnosed the multiple issues in a timely manner. Explained to me what was going on and why and hand held me through what needed to be done now and what to expect in the future. Worked on both of my units. My bill came to a FRACTION of what was recommended by company A. Mr. Moreno was very professional, kind, and honest. As a first time home owner whos been bamboozled by companies like company A, Schmidt Mechanical Group just gained a customer for life. Look forward to doing more business with them and their techs are awesome. Dont be like me and use company A first. Use this company.
I'll admit I was getting desperate. Do I let the giant commercial bad guys win? Give them all my money I could be using on fishing gear? My neighbor happens to work at Schmidt Mechanical Group (shout out to Jared) and got me in touch with their service technicians for a 2nd opinion. ENTER Richard Moreno. Showed up at the beginning of time window. Diagnosed the multiple issues in a timely manner. Explained to me what was going on and why and hand held me through what needed to be done now and what to expect in the future. Worked on both of my units. My bill came to a FRACTION of what was recommended by company A. Mr. Moreno was very professional, kind, and honest. As a first time home owner whos been bamboozled by companies like company A, Schmidt Mechanical Group just gained a customer for life. Look forward to doing more business with them and their techs are awesome. Dont be like me and use company A first. Use this company.
Maintenance Membership
Join the Care Club
Home maintenance for $9.99 a month.
Care Club members get two HVAC tune-ups and a plumbing safety inspection every year, priority scheduling, no dispatch fees — ever — and 5% off every repair.
- Priority scheduling
- Seasonal HVAC tune-ups
- Annual safety inspection
- Exclusive member discounts
- Free dispatch on repairs
- No long-term contracts
Furnace Repair Questions
Why does my furnace start, run for a few seconds and shut off?
That pattern almost always means the furnace lit but could not prove it. A gas furnace has a flame sensor, a thin metal rod in the burner flame, and if the rod is coated with the film that builds up over a summer of sitting idle, the control board cannot see the flame and closes the gas valve within seconds as a safety measure. It will try again two or three times and then lock out. Cleaning or replacing the sensor fixes it. The same symptom can come from a weak igniter, low gas pressure or a pressure switch that opens once the inducer motor is under load, so we test the whole start sequence rather than assuming.
The thermostat is calling for heat but nothing happens. What should I check before calling?
Three quick things. First, the furnace switch: most units have a light switch on or near the cabinet, and it gets bumped off in the attic or closet more often than you would think. Second, the breaker for the furnace and, on a gas unit, that the gas supply valve at the furnace is open. Third, the filter and the blower door: a badly clogged filter can trip the limit switch, and a door that is not fully latched holds the safety switch open so the furnace will not start at all. If those check out and it is still silent, leave it and call. A dead control board, a failed transformer or a fault in the thermostat wiring needs a meter to find.
Why is my furnace blowing cold air?
If the blower runs but the air never warms, the burners are not lighting or they lit and were shut down. Common causes are a failed igniter, a dirty flame sensor, a closed gas valve or a limit switch that tripped because the heat exchanger got too hot, often from a clogged filter. On a heat pump, cool air in heating mode can be a normal defrost cycle or a system that has lost refrigerant. One more thing to check: if the thermostat fan is set to “on” instead of “auto,” the blower runs constantly between heating cycles and the air it moves will feel cold. That one is a setting, not a repair.
Is it safe to run my furnace if I smell gas near it?
No. A faint gas smell for a second or two at ignition on an older furnace can happen, but a persistent rotten-egg odor near the furnace or at the registers means gas is escaping somewhere it should not. Do not flip switches, light anything or restart the furnace. Get everyone out of the house, call your gas utility’s emergency line from outside, and then call us. Once the utility has made the area safe, our technician can find the source: a leaking valve, a loose fitting on the gas line, or a burner that is not lighting cleanly. Radiant handles both the HVAC and the plumbing side of a gas problem, so you are not coordinating two companies.
Do you repair electric furnaces and heat strips, or only gas?
Both. A large share of homes in Austin and San Antonio have no gas service at all and heat with electric resistance elements inside an air handler, or with a heat pump that uses those strips as backup. The failures are different from a gas furnace: burned-out elements, sequencers that will not stage the strips on, tripped breakers from a shorted element, and thermostat wiring that never calls for auxiliary heat. Our technicians carry a meter and the common elements and sequencers on the truck. If your electric bill spikes every winter, that is often the strips running more than they should, and it is worth a look.
*Offers cannot be combined with other promotions or applied to dispatch fees. No cash value. Must present offer at time of service. Call for details.
