Last updated: June 2026
Should I repair or replace my furnace?
Repair if the furnace is under about 15 years old and the fix costs well under half the price of a new system. Lean toward replacement when the unit is 15 to 20 years old, the repair is a major part, or repair cost multiplied by the furnace's age in years tops $5,000. A new high-efficiency furnace in Ontario typically costs $4,000 to $8,500 installed.
The right call depends on age, the specific part, and how efficient your current furnace is. Below are the three rules technicians actually use, plus the Ontario prices to plug into them.
The 50% rule
If a repair would cost 50% or more of the price of a comparable new system, replacement is usually the better investment. With a new Ontario furnace running roughly $4,000 to $8,500 installed, a repair pushing past about $2,000 to $3,000 on an aging unit often signals it is time to replace. You can browse the furnaces and financing we offer to see where your number lands.
The $5,000 rule
Multiply the repair quote by the age of the furnace in years. If the result is over 5,000, replace. For example, a 10-year-old furnace facing an $800 repair scores 8,000, which points to replacement. A newer furnace with a smaller repair scores low and is worth fixing. Our companion guide on furnace repair costs gives the part prices to drop into this formula.
The age test
Gas furnaces generally last 15 to 20 years. Past that, parts get harder to find, efficiency drops and breakdowns cluster. If your furnace is in that window, a new high-efficiency model can cut energy use enough to offset much of its cost over its lifespan. Replacing an aging system is also the moment to consider a heat pump, which may qualify for an Ontario rebate, covered in our heat pump rebates guide.
What does a new furnace cost in Ontario?
As a 2026 guide, a new natural gas furnace installed in Ontario runs about $4,000 to $6,500 for most high-efficiency single-furnace jobs, with basic to premium installs spanning roughly $3,500 to $8,500. We size and install every system properly and back it with a maintenance plan to protect your investment.
How do I protect a furnace I decide to keep?
If repair wins, an annual tune-up keeps the system efficient, safe and under warranty, and is the single best way to avoid a repeat breakdown. Our maintenance plans include a yearly precision tune-up, a 21-point safety inspection and priority service. See everything we service for the full picture.
Frequently asked
When should I replace rather than repair my furnace?
Replace when the furnace is 15 to 20 years old, the repair is a major part, the fix costs near half a new system's price, or repair cost times the furnace age in years tops $5,000. Otherwise, repair is usually the better value. Ask us for an honest assessment.
How long does a furnace last?
Gas furnaces typically last 15 to 20 years. Past that range, efficiency falls, parts get scarce and breakdowns become more frequent, which is when replacement often makes more sense than another repair.
How much does a new furnace cost in Ontario?
A new high-efficiency gas furnace installed in Ontario typically costs about $4,000 to $8,500 in 2026, with most single-furnace jobs landing between $4,500 and $6,500. See the furnaces and financing we offer.
Should I switch to a heat pump instead?
Possibly. If you are replacing an aging system, a heat pump can lower energy use and may qualify for an Ontario rebate. Read our heat pump rebates guide and talk to us about the right fit for your home.
Cost figures are 2026 Ontario market ranges compiled from Canadian HVAC price guides and should be treated as estimates, not quotes. Sources: FurnacePrices.ca, "How Much Does a Furnace Cost in Canada? (2026 Prices)" (furnaceprices.ca, accessed June 2026); Custom Contracting, "Furnace & AC Replacement Cost Ontario 2026" (custom-contracting.ca, accessed June 2026); Moon's Air, "Furnace Replacement: The 50% Rule or the 5000 Rule?" (moonsair.com, accessed June 2026). The 50% and $5,000 rules are industry rules of thumb, not regional figures. Contact us for an exact quote on your home.