Furnace repair in Canada costs $150 to $900 for most faults, with major work reaching $2,500+. Canadian HVAC contractors publish a diagnostic call at $89 to $250, an igniter at $150 to $419, a blower motor at $300 to $999, and a heat exchanger at $800 to $2,500+.
Here is the part nobody tells you at 6 a.m. in January with a cold house and a technician kneeling in your basement.
The person diagnosing your furnace is very often the same person selling you the replacement. That technician arrives with a flashlight and a tablet that quotes new equipment in ninety seconds. You are cold, you are rattled, and somewhere in the conversation the phrase "cracked heat exchanger" lands like a verdict.
And under the lead-fee model most Canadian HVAC leads are bought through, that technician paid cash for the privilege of standing in your basement. A $300 repair does not pay that back. A new furnace does. The incentive is not hidden — it is arithmetic.
You do not need to be an HVAC tech to see through it. You need a price list, a rule and three questions.
• Most furnace repairs in Canada land between $150 and $900. Of the six Canadian publishers checked for this page, four state a typical repair range starting at $150, the flat-rate Calgary company starts its at $239, and the sixth publishes no range at all.
• Under 12 years, one-off fault, no safety issue → repair it.
• Age × repair quote is over $5,000 → get replacement quotes.
• Confirmed cracked heat exchanger → replace, and see the crack or a photo of it first.
• Any diagnosis that arrives with a replacement quote attached → second opinion, same week.
How much does furnace repair cost in Canada?
Canadian HVAC contractors publish furnace repairs from $80 for a flame sensor clean to $2,500+ for a heat exchanger, and which company you call moves the price more than which part failed — you can prove that from published price lists rather than taking anyone's word for it. The table below puts four Canadian HVAC contractors' own published repair prices side by side, part for part, so you can see exactly where they agree and where they do not.
Methodology: every figure in this table is a rate that column's contractor publishes on its own website, read out of the page rather than from a search snippet. Three of the four publish ranges; the fourth publishes flat rates by repair level, which is why its column carries single numbers. Advertised rates are asking prices, not quotes for your furnace.
Why does the same furnace repair cost three times more at one Canadian company than another?
Run your eye across the flame sensor row. A Hamilton contractor starts that job at $80. A Calgary contractor charges a flat $239 for it. The flame sensor is the same part on the same kind of furnace, priced three times apart — and neither company is doing anything improper. The two companies are using different pricing models.
The flat-rate column is the one worth understanding, because it behaves differently from the others. The Calgary flat-rate company charges $239 whether the job takes twenty minutes or two hours, and $999 for a blower motor where the three range-based publishers sit between $300 and $900. On a quick job you pay more. On an awkward one you pay less, and you knew the number before anyone opened the cabinet.
The ceilings tell the same story. Two publishers stop the heat exchanger at $1,500 or more, the BC publisher runs to $2,500 or more, and the Calgary flat-rate company prices an in-warranty plugged exchanger at $1,799. Six Canadian publishers were checked for this page, two more than the four whose part-by-part rates fill the table above: four of the six state a typical repair range that starts at $150, the flat-rate Calgary company starts its at $239, and the sixth publishes no range at all — so the bottom of this market is broadly agreed, and the ceiling is where the disagreement lives, which is precisely the region of the price list where a replacement gets suggested.
What is the $5,000 rule for HVAC, and does it hold up in Canada?
The $5,000 rule is an HVAC industry rule of thumb: multiply the furnace's age in years by the quoted repair cost. If the result is above $5,000, replacement is usually the better long-term move. If it is below $5,000, repair the furnace. A 12-year-old furnace with a $500 repair scores $6,000 and points to replacement; a 7-year-old furnace with a $400 repair scores $2,800 and points to a repair.
The rule inverts cleanly. Divide $5,000 by the age of your furnace and you get the repair quote at which the rule flips. The table below shows that break-even repair cost for each furnace age, which is the number to hold in your head while a technician talks.
Now lay that against the published repair prices and the rule gets sharper. At 15 years the rule flips at $333 — and at three of the four publishers here, a blower motor, control board, inducer motor or gas valve starts at or above that. The Hamilton contractor is the exception, with entry prices of $200 to $300 on all four of those parts, and one Calgary gas valve also starts at $300. At 25 years the rule flips at $200, which is at or below any diagnostic-plus-repair combination these four contractors publish.
One honest caveat: the $5,000 threshold was set when equipment cost less, so it is a conservative trigger. A Calgary contractor publishes its own cruder version of the same idea — if the repair runs $1,000 or more, replacement can be the smart financial move — and a BC contractor uses a third: if the repair exceeds half the cost of a new furnace, get a replacement quote before agreeing to anything. Treat a score just over $5,000 as a reason to collect quotes, not to sign one that afternoon.
Should a 25 year old furnace be replaced?
A 25-year-old furnace should be replaced. A well-maintained furnace in Canada lasts about 15 to 20 years, so a 25-year unit is running five to ten years past its expected service life, and the $5,000 rule breaks at a repair quote of only $200 at that age. Almost nothing a technician can be called out for costs less than that — a diagnostic call alone starts at $89, before any part is fitted.
Age matters for two reasons beyond reliability. Parts availability is the first: control boards, gas valves and inducer motors for furnaces from the late 1990s and early 2000s are increasingly sourced from salvage rather than stock, which turns a one-day repair into a week without heat in February. One Calgary publisher puts a number on it, adding $100 to $300 in parts markup and one to two weeks of delay on furnaces 15 years and older.
Efficiency is the second. A furnace of that vintage is typically a mid-efficiency unit around 80% AFUE, meaning roughly a fifth of the gas you buy goes up the flue. AFUE — Annual Fuel Utilization Efficiency — is the share of fuel a furnace converts into heat in your home, and today's high-efficiency units run 90% to 98%.
One legitimate exception: if a 25-year-old furnace is heating a home you are selling within months, a cheap repair to get through the season is a defensible commercial choice — provided the fault is not a safety fault. A cracked heat exchanger is never a "get through the season" item.
Which furnace problems in Canada are only a repair?
Most winter furnace call-outs across Canada are small parts and airflow faults, not equipment failure. None of the following is a reason to replace a furnace on its own, and none of them is expensive: where these four publishers price them at all, they sit at the bottom of the list — the Calgary flat-rate company prices thermostat, condensate and vent work at its lowest tier of $239, and a blocked filter assembly at $109 to $239.
- A clogged air filter. A dirty filter starves the burner of return air, trips the high-limit switch, and makes a perfectly healthy furnace short-cycle. One BC contractor puts it plainly: a $15 filter protects a $600+ motor.
- A dirty flame sensor. Named by a BC publisher as the single most common cause of no-heat calls. Cleaning it takes minutes during a tune-up — as an emergency repair on a February night that same BC publisher puts it at $150 to $220.
- A failed hot surface ignitor. A brittle ceramic part that cracks with thermal cycling. The furnace clicks, tries, and gives up. Published at $150 to $419 depending on who you call.
- A thermostat fault or a dead thermostat battery. No heat at all, and nothing wrong with the furnace.
- A blocked condensate drain on a high-efficiency furnace. Water backs up, the pressure switch opens, the furnace locks out.
- A blocked exterior intake or exhaust vent. Snow and ice on the side-wall PVC vents of a high-efficiency furnace shut it down on a safety lockout. Clearing the vent is the fix.
If a technician diagnoses any item on that list and the conversation still ends at a replacement quote, the diagnosis and the recommendation are not connected. That mismatch is your cue to stop and get a second opinion.
Which furnace symptoms mean replace now?
Four symptoms move a furnace out of the repair conversation entirely, regardless of what the $5,000 rule scores or what the price table says.
- A confirmed cracked heat exchanger. The heat exchanger is the metal chamber that separates combustion gases from the air blown through your ducts. A crack lets carbon monoxide reach the air you breathe, and a gas technician will shut down and red-tag a furnace with a confirmed crack.
- Soot or yellow burner flames. A healthy natural gas burner flame is blue and steady. Yellow, lazy or lifting flames and black soot inside the cabinet indicate incomplete combustion on a furnace at or past 15 years.
- A carbon monoxide alarm that trips when the furnace runs. Leave the house, call 911 or your gas utility's emergency line, and do not run the furnace again until a licensed gas technician has cleared it.
- Two or more failures in two heating seasons on a furnace over 15 years. Repair frequency, not any single repair price, is what tells you the equipment is at end of life.
On carbon monoxide, Ontario's safety regulator is blunt about where the risk actually comes from: improper installation and poor work are identified as the major contributing factors in fuel and carbon monoxide incidents. A working CO alarm is the cheapest independent check you have on any technician's combustion claims.
Is a cracked heat exchanger a real reason to replace a furnace?
A genuinely cracked heat exchanger is a real reason to replace a furnace, and it is also the most commonly abused diagnosis in the trade. Both things are true, which is why it has to be handled with evidence rather than trust. Across all four published price lists, the heat exchanger is the single most expensive component, and replacing one means stripping the cabinet down to its core — so on a furnace past 15 years, a confirmed crack normally ends in a full replacement rather than a part swap.
The claim is easy to make and hard to see: the heat exchanger sits inside the furnace cabinet behind the burner assembly, where no homeowner can casually verify it. So refuse the diagnosis without evidence.
The table below lists what those flags sound like in a real basement conversation, and why each one matters.
✓ "Show me the crack, or take a photo of it with your inspection camera and send it to me."
✓ "Which section of the heat exchanger, and what test confirmed it?"
✓ "Put the diagnosis in writing, with your gas technician certificate number on it."
✓ "If you are red-tagging the furnace, give me the red tag and the written violation."
✓ "What is the repair price, separately from the replacement price?"
✓ "I am getting a second opinion before I buy equipment. Leave the furnace shut down."
A technician with a real finding will answer all six without flinching. Book the second opinion from a company with no stake in the first quote, and pay the diagnostic fee if you have to. At $89 to $250, a diagnostic fee is the cheapest way to avoid a four-figure mistake.
How do you check a furnace technician before they diagnose anything?
Gas work is licensed province by province in Canada, and the licence is checkable before anyone opens your furnace cabinet. In Ontario the Technical Standards and Safety Authority certifies fuels safety technicians under Ontario Regulation 215/01, and states that furnaces and fuel-fired appliances must be maintained by TSSA-registered contractors. Other provinces run their own authorities and their own gasfitter licensing — a BC contractor on this page notes that a gas valve replacement there requires a licensed gasfitter.
Ask three questions before work starts, and ask them on the phone rather than in the basement.
- Is the company registered with the provincial authority, and what is its registration number? Ontario's regulator maintains a searchable database of registered fuels contractors and points out that unregistered workers' jobs cannot be audited for compliance and their credentials cannot be validated.
- Which certificate does the technician attending hold? Gas certificates are tiered, and the higher tiers require thousands of hours at the level below. Ask which tier is coming to your house.
- Is there workers' compensation coverage, and who pays if the furnace or the house is damaged? Workers' compensation covers the worker; liability covers damage to your ductwork, your floors or your neighbour's property. Workers' compensation and liability cover are separate documents from separate bodies, and every province runs its own compensation board.
Why does one company say repair and the next says replace?
Follow the money and the disagreement stops being mysterious. On the dominant lead-generation model in Canadian home services, a contractor pays a fee for each lead, the same lead is commonly sold to several contractors at once, and many are locked into annual contracts on top. A technician who paid for your name and is racing three other companies to your basement is not neutral about whether you need a $150 igniter or a new furnace.
TaskRight runs the opposite model. Pros pay one flat subscription and 0% commission — they keep 100% of every job. No per-lead fee, no lead sold four times over, no bidding war that has to be recovered out of your quote. You post the job once, you compare the quotes side by side, and you choose. Nobody paid for the right to talk you into a replacement.
Which is exactly what you want in a repair-or-replace decision: a second opinion from someone with no reason to prefer one answer over the other.
TaskRight is a verified, zero-commission home services platform in Canada. Get your furnace looked at by a technician who gets paid the same whether the answer is a $150 part or a new system — then decide.
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Furnace repair cost in Canada: frequently asked questions
How much does furnace repair cost in Canada?
Most furnace repairs in Canada fall between $150 and $900. Canadian contractors publish a diagnostic call at $89 to $250, an igniter at $150 to $419 and a blower motor at $300 to $999. Major work such as a heat exchanger runs $800 to $2,500+ and often makes replacement the better financial choice.
What is the most expensive repair on a furnace?
The heat exchanger is the priciest furnace repair in Canada, published at $800 to $1,500+ by two contractors and $900 to $2,500+ by a third. Replacing one means stripping the furnace cabinet down to its core, so labour dominates the bill. Past 15 years, a confirmed crack normally ends in full replacement.
What are the most common furnace repairs?
Flame sensors, igniters and thermostats are the most common furnace repairs in Canada, followed by pressure switches and blower motors. A dirty flame sensor is named by one BC contractor as the single most common no-heat cause, and one Hamilton contractor publishes it at $80 to $150 to clean and $150 to $300 to replace. All of them are repairs, not reasons to replace a furnace.
Should a 25 year old furnace be replaced?
A 25-year-old furnace should be replaced. A well-maintained furnace in Canada lasts about 15 to 20 years, so a 25-year unit is past end of life, and the $5,000 rule breaks at just $200 of repair at that age. A diagnostic call alone starts at $89, before any part is fitted.
Is it worth fixing a home heating furnace?
Fixing a furnace is worth it under about 12 years old when the fault is a one-off and there is no combustion or carbon monoxide problem. Multiply the age by the repair quote: under $5,000 favours repair. One Canadian contractor uses a simpler trigger, treating a repair of $1,000 or more as a reason to price replacement.
What is the $5,000 rule for HVAC?
The $5,000 rule is an HVAC rule of thumb: multiply the furnace's age in years by the quoted repair cost. Above $5,000, replace; below, repair. A 12-year-old furnace facing a $500 repair scores $6,000 and points to replacement. Rising equipment costs have made the threshold conservative, so treat it as a trigger to collect quotes.
Sources and methodology
Every repair price on this page is a published rate from a Canadian HVAC contractor's own website — one in Hamilton, two in Calgary, one in Coquitlam, one in Ottawa and one more in Ontario — read directly out of each page rather than from a search result. The four-column price table carries the four contractors that publish part-by-part rates; the other two are used only to corroborate the typical range. Advertised rates are asking prices, not quotes for your furnace, and none of them is TaskRight quote data.
Two things we found while checking sources are worth passing on, because they change how you should read furnace pricing online. The first is that a major manufacturer's Canadian furnace page presents its cost figures as CAD while attributing them to a United States home-services database — and the "CAD" numbers are the American ones multiplied by exactly 1.35. The same page prints both versions of one furnace replacement range, $3,800 to $10,000 in one place and $5,130 to $13,500 "CAD" in another. We excluded it as a price source for that reason.
The second finding is simpler. When we checked in August 2026, a page ranking on Google's first page in Canada for this exact search published no dollar figure anywhere in its 95,000 bytes of markup, despite a heading promising the average furnace repair cost. A page can rank well and still not answer the question, which is a reasonable argument for checking two or three published price lists rather than trusting the first result.
Regulatory points come from the Technical Standards and Safety Authority's fuels certification pages and its guidance on unregistered fuels workers, which apply in Ontario. Gas licensing, workers' compensation and permit rules differ in every province — confirm the requirements with your own provincial authority before booking work.
Last updated: August 2026
Related reading:
- Furnace replacement cost in Canada — if the answer here is replace, that guide has what a new furnace costs by home size and efficiency tier, and what a fair quote must itemise.
- Duct cleaning cost — the other HVAC job that gets sold hardest at the door, and what it should actually cost.
- Heating and cooling pros on TaskRight — compare verified HVAC pros across Canada.
