Furnace repair when the heat is out
No heat? Most repairs start with a $100 to $200 diagnostic. Gas smell or CO alarm? Get outside first.
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Gas smell or a carbon monoxide alarm? Get outside first.
If you smell rotten eggs or hear gas hissing, get everyone outside now. Do not flip light switches, unplug anything, use a phone inside or look for the leak. Once you are outside, reach your gas utility's emergency line or emergency services.
If a carbon monoxide alarm sounds, or people feel headachy, dizzy or sick indoors, leave and get help from outside. This site lists no phone numbers and is not an emergency service.
Safe checks before you book
Ten minutes, no tools. Leave the burners, gas valve and wiring to a technician.
- Thermostat. Make sure it says Heat and is set a few degrees above the room. A blank screen usually means dead batteries.
- Power. The furnace switch (it looks like a light switch) is on, and its breaker has not tripped.
- Filter. A clogged filter can overheat the furnace until it shuts off. If you cannot see light through it, swap it.
- Furnace door. The lower door presses a safety switch. If it is not seated firmly, the furnace will not start.
- Condensate. A blocked drain trap or a full condensate pump shuts a high-efficiency furnace down.
- Vent pipes. The two plastic pipes outside must be clear of snow, ice and nests. Clear them gently by hand.
- Error code. Count the blinking light behind the small window in the door and match it to the chart inside the door.
Fixed something? Switch the furnace off for 30 seconds, then on, once. If it shuts down again, stop resetting and request a repair visit through FurnaceQuotes.ca.
While you wait for the repair
- Close curtains at night and keep interior doors shut.
- Prop open sink cabinets on outside walls, and leave a tap dripping if pipes might freeze.
- Plug space heaters straight into a wall outlet, 1 metre from anything that can burn. Never heat with an oven, barbecue or camp heater.
Common furnace problems and typical repair prices
Match the symptom, then expect a diagnostic visit to confirm it. Prices assume a high-efficiency gas furnace.
- Diagnostic visit
- $100 to $200Ask if it is credited
- Most common fixes
- $150 to $450Igniter, flame sensor, pressure switch
- Bigger repairs
- $450 to $1,800Motors, control board, gas valve
| What you notice | Likely cause | Typical price |
|---|---|---|
| Inducer fan runs, but no orange glow and the burners never light | Hot surface igniter | $250 to $450 |
| Burners light, then shut off after a few seconds, over and over | Dirty or failed flame sensor | $150 to $300 |
| Nothing lights and the blink code points to pressure | Pressure switch, or a blocked vent or drain | $250 to $450 |
| Loud whine, rattle or grinding at start-up | Inducer motor | $600 to $1,200 |
| Burners run but little or no air comes from the vents | Blower motor: PSC on older furnaces, ECM on newer ones | $500 to $900 PSC $900 to $1,800 ECM |
| No response once power is confirmed, or erratic behaviour | Control board | $500 to $1,100 |
| Igniter glows but the burners never light | Gas valve, or the gas supply is off | $450 to $900 |
| A crack, rust-through or carbon monoxide in the exhaust | Cracked heat exchanger | Often replacement-level |
| Not sure what is wrong | Diagnostic or service call | $100 to $200 |
Under about 10 years old and registered? The part may still be under the manufacturer's parts warranty, leaving labour only. Renting? Contact the rental provider first: repairs are normally included.
Repair or replace?
One repair on a healthy furnace is usually worth it. Compare with a replacement price when the furnace is old, the repair is big or the heat exchanger is cracked.
Repair usually makes sense
- The furnace is under about 12 years old
- One part failed and the rest checks out
- The part is still under warranty
- The heat exchanger is sound and the exhaust tests clean
Get a replacement quote too
- The furnace is 15 to 20 years old or more
- The repair runs into four figures, against $4,000 to $6,500 for a new standard furnace installed
- The heat exchanger is cracked
- It is an older 80% furnace, or it needed repairs each of the last two winters
Worked example: a 17-year-old furnace needs an ECM blower motor at $900 to $1,800. The middle of that range is about 26% of a new single-stage furnace, and you would still own a 17-year-old furnace. Price a replacement first. Going from an 80% to a 96% furnace also cuts gas use by about 17%.
Told the heat exchanger is cracked? A technician can shut off a furnace they find unsafe, and that is a safety step. You can still ask to see the crack or the carbon monoxide reading, and test any replacement price with the quote checker.
Try the furnace price estimator, or request a furnace replacement quote too.
Furnace tune-ups
A yearly tune-up typically costs $120 to $250 and catches the parts most likely to fail before the first cold snap.
A good tune-up includes
- Clean the flame sensor and check the burners
- Inspect the igniter, inducer, blower and safety switches
- Check gas pressure and temperature rise
- Inspect the heat exchanger and test the exhaust for carbon monoxide
- Clean the condensate trap and check the vent pipes
Book it in early fall, before the busy season. Some manufacturer warranties expect regular maintenance, so keep the receipts.
If a tune-up ends in a pitch for a new furnace, ask for the reason in writing and get a second price.
What to ask the technician
Ask before work starts, and get the answers on the invoice.
- Will the diagnostic fee come off the repair bill?
- Is the price flat-rate or time and materials? Can I have it in writing first?
- How long is the warranty on the part, and on the labour?
- Is it an original manufacturer part or a universal one?
- If you say it is unsafe, what exactly did you find?
More in what to ask before you sign.
Gas work in Ontario
In Ontario, only a TSSA-registered contractor, using certified gas technicians, may install or repair gas appliances. Ask for the company's TSSA registration number and the technician's certificate before work starts. We do not certify, license or inspect any company.
What happens after you send a request
Tell us what is happening
About a minute. Choose Urgent if you have no heat.
A quick call to book
Our booking team calls to confirm details and a time. The call can be automated or AI-assisted.
A repair visit
A participating local company diagnoses the furnace and prices the repair before starting.
You decide
Approve the repair, ask for a replacement price to compare, or stop at the diagnosis.
Common questions
Straight answers. If yours is not here, the company can answer it during your free estimate.
How much does furnace repair cost in Ontario?
Most visits start with a diagnostic at $100 to $200. Common fixes such as an igniter, flame sensor or pressure switch typically run $150 to $450 with parts and labour, before HST. Motors, control boards and gas valves cost more, up to $900 to $1,800 for an ECM blower motor.
Why does my furnace turn on, then shut off after a few seconds?
Usually a dirty flame sensor: the burners light, the furnace cannot confirm the flame, and it shuts the gas off for safety. A blocked vent pipe, a full condensate trap or a clogged filter can cause similar short runs. Cleaning or replacing the sensor typically costs $150 to $300.
Can I reset my furnace myself?
Turn it off at the furnace switch for 30 seconds and back on, once. Note the blink code first, because cutting power can clear it. If it locks out again, stop. Repeated resets will not fix a failed part and can make a safety fault harder to find.
Should I fix a furnace that is 15 years old?
It depends on the repair. A $250 to $450 igniter on a furnace in good shape is usually worth it. A four-figure repair, a cracked heat exchanger or repeat breakdowns are the point to compare with a new furnace at $4,000 to $6,500. A gas furnace typically lasts 15 to 20 years.
Who pays for repairs on a rented furnace?
Usually the rental provider. Most Ontario furnace rental agreements include repairs for the term, so contact the provider first and do not pay another company to work on equipment you do not own. Check the agreement for exclusions.
How fast can someone come out for a no-heat call?
It depends on the company's schedule and the weather, and cold snaps are the busiest time. Choose Urgent so your request is flagged that way. Booking at the first odd noise, not after a full breakdown, gives you more choice of times.
No heat? Send a repair request
About a minute. Choose Urgent and our booking team calls to set up a repair visit with a participating local HVAC company.
Takes under a minute. No cost, no commitment.