Furnace Repair or Replace in Toronto? 2026 Decision Guide

Every Toronto winter we get the same call: the furnace is 15 years old, the repair quote is $900, and the homeowner wants to know whether that money is worth spending. Here is the framework our TSSA-licensed technicians use on site, with real 2026 GTA numbers so you can decide before the next cold snap.

The 50% rule, adapted for GTA prices

The classic advice is to replace when a repair costs more than 50% of a new unit. In the GTA a mid-efficiency to high-efficiency furnace replacement runs roughly $4,500 to $7,500 installed, so a $900 repair on a healthy 9-year-old furnace is easy math — fix it. The same $900 on an 18-year-old unit that already needed a control board last winter is money you will spend again.

Multiply the repair quote by the furnace's age. If the result is above about $50,000, replacement is usually the better long-term value. A $900 repair on an 18-year-old furnace scores $16,200 — borderline. A $2,400 heat exchanger job on that same furnace scores $43,200 and, combined with the safety risk, points firmly at replacement.

Repairs that are almost always worth it

• Igniter or flame sensor — $180 to $350, and the rest of the furnace is untouched.
• Thermocouple, pressure switch, limit switch — under $400 in most GTA homes.
• Blower capacitor — inexpensive, and a classic cause of a furnace running but not moving air.
• Draft inducer motor — $500 to $900, worth it under roughly 12 years of age.

If your furnace is under 12 and has had no major failures, repair almost always wins. See our furnace repair service for what a visit includes.

Repairs that usually mean it is time to replace

A cracked heat exchanger is the clearest signal. It is a carbon monoxide risk, it typically costs $1,500 to $3,000 to address, and on an older unit the rest of the system is on the same clock. Repeated control board failures, a furnace that has needed three or more service calls in two seasons, or a unit that can no longer hold temperature on the coldest nights all belong in the replace column.

How old is too old for a furnace in Toronto?

Most gas furnaces in the GTA last 15 to 20 years. Toronto's long heating season pushes real-world life toward the lower end of that range, especially for units that were never serviced annually. Past 15 years, treat any repair over roughly $800 as a replacement conversation. Past 20 years, efficiency alone usually justifies replacement: an old 80% AFUE unit wastes about a fifth of every gas dollar compared with a 96% AFUE furnace.

What does a new furnace cost in the GTA in 2026?

A high-efficiency gas furnace, professionally installed with permits and a TSSA-compliant venting inspection, typically lands between $4,500 and $7,500 for a standard Toronto home. Larger homes, difficult venting runs, or a switch to a variable-speed unit can push the total toward $9,000. Cold-climate heat pump conversions start higher but change the operating-cost picture. Run your own numbers with our price calculator before you take a quote.

Are there rebates for replacing a furnace in Ontario?

Rebate programs in Ontario change from year to year and are usually tied to efficiency ratings, heat pump conversions, or a pre-retrofit energy assessment rather than a straight like-for-like furnace swap. Before you book a replacement, check the current federal and provincial program pages and confirm your installer files the paperwork. Ask for the model's AFUE or HSPF rating in writing — it is what every program is scored on.

Should I replace my furnace and AC at the same time?

Often yes, if both are within a few years of each other in age. A furnace and AC share the blower and the ductwork, and matched equipment runs more efficiently than a new furnace paired with a 16-year-old condenser. Doing both in one visit also saves a second installation labour charge. If your AC is under 10 years old, there is no reason to touch it.

What should a replacement quote include?

Insist that the written quote lists the equipment model and AFUE rating, the permit, removal and disposal of the old unit, any venting or gas line modifications, thermostat, and the labour warranty separate from the manufacturer's parts warranty. A quote that is a single number with no line items is how surprise charges happen.

Get a straight answer before you spend

If you are staring at a repair quote and are not sure, we will give you the repair-versus-replace math on the spot, in writing, with no obligation. [Book a free assessment](/contact) or call us at (647) 000-0000 — same-day appointments are usually available across Toronto, Mississauga, Vaughan and the rest of the GTA.