Furnace repair cost in Ontario (2026)
Most furnace repairs in Ontario cost between $150 and $1,800 before HST, plus a diagnostic visit of $100 to $200. Igniters, flame sensors and pressure switches sit at the low end; motors, control boards and gas valves cost the most.
- Diagnostic or service callSome companies credit it toward the repair.$100 to $200
- Hot surface igniterA frequent no-heat repair; the part wears out.$250 to $450
- Flame sensor clean or replaceOften just a cleaning, the low end.$150 to $300
- Pressure switchCheck the hose and vent before replacing it.$250 to $450
- Inducer motorThe fan that pushes exhaust out the vent.$600 to $1,200
- Blower motor (PSC)Older single-speed motor.$500 to $900
- Blower motor (ECM)Variable-speed motor on many newer furnaces.$900 to $1,800
- Control boardSurges and drain leaks are common culprits.$500 to $1,100
- Gas valveLess common; replaced, never repaired.$450 to $900
Ranges cover part, labour and visit for a standard gas furnace in regular hours. Add 13% HST: an igniter at $250 to $450 is $283 to $508 on the invoice. To weigh a large repair against replacement, check installed prices in the Ontario Furnace Prices price index.
- Diagnostic visit
- $100 to $200Before any repair
- Typical small repair
- $150 to $450Igniter, flame sensor, pressure switch
- Typical large repair
- $500 to $1,800Motors, control board, gas valve
- New single-stage furnace
- $4,000 to $6,500Installed, for comparison
On this page
- What usually breaks, by symptom
- What moves the price of the same repair
- If the heat goes out on a cold night
- Checks you can safely do before you book
- A cracked heat exchanger is usually a replacement decision
- Warranty: parts often covered, labour often not
- When to stop repairing
- How to keep the bill fair
- Questions people ask
Smell gas or hear a carbon monoxide alarm? Get out first.
If you smell gas (a rotten-egg odour), get everyone out without touching switches, phones or the thermostat, then call your gas utility's emergency line or 911 from outside. If a carbon monoxide alarm sounds, get everyone into fresh air and call 911. Do not go back in to check the furnace.
What usually breaks, by symptom
Technicians price by the part; you notice the symptom. This table links the two. It is a guide, not a diagnosis: one symptom can have a cheap cause or an expensive one.
| What you notice | Common causes | Typical repair |
|---|---|---|
| No heat, furnace silent | Thermostat setting or batteries, tripped breaker, service switch off, loose door panel, failed control board | Free (a setting) to $1,100 |
| Inducer runs, burners never light | Worn hot surface igniter, pressure switch, blocked vent or intake pipe | $250 to $450 |
| Burners light, then shut off within seconds | Dirty flame sensor, poor ground, gas supply problem | $150 to $300 |
| Runs a few minutes, stops, repeats | Clogged filter, blocked vent, overheating limit switch, furnace too large for the house | A filter to $450 |
| Blower runs but the air is cold | Burners not lighting, thermostat fan set to On, overheating lockout | $150 to $450 |
| Humming, grinding or squealing | Worn inducer or blower motor bearings | $500 to $1,800 |
| Water on the floor around the furnace | Clogged condensate trap or drain, failed condensate pump, humidifier or AC coil drain leak | A service call to $350 |
| Yellow or lazy flame, soot, CO alarm | Combustion problem, blocked flue, possible cracked heat exchanger | Stop using it and have it inspected |
Before 13% HST, regular hours, standard residential gas furnace. A condensate pump replacement is typically $150 to $350.
What moves the price of the same repair
-
Evenings, weekends and holidays
Raises the price: Higher rate
Most companies charge more outside regular hours, and a no-heat call in the first cold snap waits in line with everyone else's.
-
ECM versus PSC blower motor
Raises the price: $900 to $1,800 vs $500 to $900
Variable-speed motors cost more. On some, only the electronic module fails and can be replaced on its own; ask.
-
Factory or universal part
Can go either way: Either way
A universal board or valve can be cheaper or faster to source; a factory part matches the original. Under parts warranty, the factory part is usually supplied and you pay labour.
-
A second fault behind the first
Raises the price: Adds a line
A failed pressure switch can be a symptom of a blocked vent. Fixing the cause costs more today and saves a repeat visit.
-
Diagnostic credited to the repair
Lowers the price: Saves $100 to $200
Some companies fold the service call into the repair price when you approve the work on the spot. Ask before they start.
If the heat goes out on a cold night
After-hours calls cost more, so decide whether yours can wait.
Do the safe checks first
The list below takes ten minutes.
Decide whether it can wait
If the house stays well above freezing and everyone is healthy, extra layers and an electric space heater plugged straight into the wall, clear of bedding, can carry you to morning. Open cabinet doors under sinks on outside walls.
Book the emergency call when it cannot
An infant, an older or unwell person at home, or a house sliding toward freezing justify the after-hours rate. Ask the visit price before the technician is dispatched.
Checks you can safely do before you book
Some no-heat calls end with a setting, a switch or a filter. These checks are safe for any homeowner and can save the diagnostic fee.
- Thermostat: set to Heat, a few degrees above room temperature, with fresh batteries.
- Power: the furnace breaker and the service switch, which looks like a light switch on or near the furnace, are both on.
- Door panel: the blower door is fully seated; a safety switch keeps the furnace off when it is loose.
- Filter: a clogged filter can make the furnace overheat and shut down. Replace it if no light shows through.
- Vent pipes outside: on a high-efficiency furnace, the plastic intake and exhaust pipes must be clear of snow, ice and leaves.
- Condensate drain: a clogged trap or a full condensate pump stops a high-efficiency furnace. Look for water.
- Light code: note the flashing pattern and match it to the legend on the door. It speeds up diagnosis.
What to leave to a gas technician
Anything beyond the filter, switches and thermostat is gas work: burners, igniter, flame sensor, gas valve, piping, venting connections and the heat exchanger. In Ontario, furnaces must be serviced by a TSSA-registered fuels contractor using certified gas technicians. Ask for the registration number and check it with TSSA's contractor lookup. And do not keep pressing reset on a furnace that locks out: the lockout is a safety feature.
Want the real number for your repair?
Describe the symptom and get a free, no-obligation quote from a participating local heating and cooling company.
Free, no obligation. About a minute to request.
A cracked heat exchanger is usually a replacement decision
The heat exchanger is the metal wall between the flame and the air you breathe. When it cracks, combustion gases, including carbon monoxide, can reach the house air. A technician who finds a crack will normally shut the furnace off and tag it as unsafe until the condition is fixed.
Replacing one means taking most of the furnace apart. Even when the part is under warranty, the labour is a large share of a new furnace's price, and the rest of the cabinet is just as old. Compare it against a new single-stage furnace at $4,000 to $6,500 installed (see furnace installation cost); on an older furnace, the new one usually wins.
If you are told the heat exchanger is cracked, ask
- Show me the crack: a photo, a camera inspection or the combustion readings.
- Put the finding and the reason for the shut-off in writing.
- Give me two written prices: the heat exchanger repair, and a replacement furnace.
Get a second opinion before you replace. Any TSSA-registered contractor can repair the condition or replace the furnace; it does not have to be the company that found it.
Warranty: parts often covered, labour often not
Most furnace makers offer a limited parts warranty, commonly 10 years, if the furnace is registered within a set period after installation; unregistered, the term is often shorter. Labour is usually not covered, so a warranty igniter can still cost the visit and an hour of work.
Your installer may have given a separate labour warranty. Before you book, find the paperwork or look up the serial number from the rating plate on the manufacturer's website. A rented furnace is different again: repairs are normally the rental company's job (see rent or buy a furnace).
When to stop repairing
A repair makes sense on a furnace that is young, safe and keeping the house comfortable. Three signals point the other way:
- Age. Most gas furnaces last about 15 to 20 years (see how long furnaces last). Past 15, a large repair buys time on parts that are all the same age.
- Repeat visits. Two or more significant repairs within two heating seasons.
- The size of the bill. A common trade rule of thumb multiplies the furnace's age by the repair price: over about $5,000, get a replacement quote. It is a heuristic, not a verdict.
| Situation | Age times repair | Lean |
|---|---|---|
| 9-year-old furnace, pressure switch at $350 | 9 × $350 = $3,150 | Repair |
| 13-year-old furnace, control board at $800 | 13 × $800 = $10,400 | Get a replacement price too |
| 18-year-old furnace, ECM blower motor at $1,400 | 18 × $1,400 = $25,200 | Lean toward replacing |
Safety problems override the arithmetic.
For a fuller answer that also weighs efficiency, safety flags and how long you plan to stay, run your furnace through the repair or replace check.
How to keep the bill fair
Questions to ask before you approve a repair
- Is the diagnostic fee credited if I approve the repair?
- Does the price include the part, labour and HST?
- Which part failed, and what caused it?
- Factory or universal part, what warranty comes with it, and is the furnace itself still under warranty?
For anything over about $1,000, or advice to replace, a second written opinion is worth another diagnostic fee. Better still, a yearly tune-up at $120 to $250 catches dirty sensors, worn igniters and blocked drains before a cold night: see furnace maintenance cost, or AC repair cost for the cooling side.
Questions people ask
How much is a furnace service call in Ontario?
A diagnostic or service call typically costs $100 to $200 before HST during regular hours. It covers travel and the time to find the fault; the repair is priced separately. Evenings, weekends and holidays usually cost more. Some companies credit the fee toward the repair if you approve it on the spot, so ask when you book.
How much does it cost to replace a furnace igniter?
A hot surface igniter replacement typically costs $250 to $450 in Ontario before HST, including the part, labour and visit. Igniters are fragile and wear out with use, which makes them one of the more frequent no-heat repairs. The igniter sits beside the burners, so in Ontario it is a job for a certified gas technician, not a homeowner.
Which furnace repairs are worth doing on an older furnace?
Small, common parts usually are: an igniter or flame sensor at $150 to $450 can buy more winters. For an inducer or blower motor on a furnace past about 15 years, get a replacement price alongside the repair price, and a cracked heat exchanger at that age usually means replacement. The repair or replace quiz weighs age, repair cost and safety for your own furnace.
Can I clean a furnace flame sensor myself?
Online videos show it, but the sensor sits in the burner compartment of a gas appliance, and in Ontario furnaces must be serviced by a TSSA-registered contractor using certified gas technicians. A good tune-up includes the cleaning; a stand-alone visit typically costs $150 to $300. Homeowner checks stop at the thermostat, switches, filter and vents.
Does home insurance cover furnace repairs?
Usually not. Standard home policies generally exclude wear and tear and mechanical breakdown, which describes most furnace failures. Some insurers sell an equipment breakdown add-on, and some homeowners carry a separate protection plan. Read the exclusions and claim limits of either, and check your own policy before you assume a repair is covered.