The honest answer most Toronto homeowners are looking for: a new gas furnace installed in the GTA typically runs $4,000 to $8,500 in 2026, with the majority of standard single-family replacements landing between $5,000 and $7,000. That figure includes the unit, installation labour, permits, and safe disposal of the old furnace.
But a price range that wide isn't very useful on its own. Below is what actually moves the number — so you can walk into a quote knowing whether you're being quoted fairly.
2026 furnace price ranges by efficiency
Furnaces are rated by AFUE (Annual Fuel Utilization Efficiency) — the percentage of fuel converted to usable heat. In Ontario, new gas furnaces must be at least 95% AFUE.
| Furnace type | Typical installed cost | Best for |
|---|---|---|
| Mid-efficiency single-stage (96% AFUE) | $4,000 – $5,500 | Budget replacements, rentals |
| Two-stage (96–97% AFUE) | $5,500 – $7,000 | Most Toronto homes |
| Modulating + variable-speed (98% AFUE) | $7,000 – $9,000+ | Comfort, quiet operation, larger homes |
A modulating furnace with a variable-speed blower costs more up front but runs quieter, holds a steadier temperature, and uses less electricity than an old single-speed blower. For a home you plan to stay in, the two-stage or modulating tier is usually the sweet spot.
What drives your price up or down
Furnace size (BTU) and a proper load calculation
Bigger isn't better. An oversized furnace short cycles, wears out faster, and heats unevenly. The right size comes from a Manual J load calculation based on your home's square footage, insulation, windows, and layout — not from simply matching the BTU of your old unit. Any installer who skips this step is guessing.
The condition of your existing setup
Costs climb when the new furnace doesn't drop cleanly into the old one's footprint. Common add-ons:
- New venting or a change from mid- to high-efficiency exhaust ($300–$800)
- Gas line resizing or relocation
- Ductwork modifications or a new plenum
- A new condensate drain and pump for high-efficiency units ($150–$400)
- Electrical or thermostat upgrades
Rebates and financing
Ontario homeowners can sometimes offset furnace or heat-pump upgrades through provincial and utility efficiency programs. Program names and amounts change year to year, so confirm what's active before you buy — a reputable installer will tell you what you actually qualify for rather than promising a headline number.
Two ways Toronto homeowners overpay
1. Emergency replacement in January. When your furnace dies in a cold snap, you have no leverage and little time to compare quotes. If your unit is 15+ years old and limping, replacing it in the shoulder season (spring or fall) almost always costs less and gives you room to choose.
2. Paying for a brand name, not an install. A mid-tier furnace installed correctly will outperform a premium unit installed poorly. Sizing, sealing, venting, and commissioning matter more than the badge on the cabinet. Ask how the installer sizes the unit and whether commissioning (measuring gas pressure and temperature rise) is included.
Repair or replace?
A reasonable rule of thumb: if your furnace is over 15 years old and the repair costs more than a third of a new unit, replacement usually wins. Rising repair frequency, a cracked heat exchanger, or a yellow burner flame all push toward replacement. If your unit is under 10 years old, a targeted repair is often the smarter money.
What a fair quote should include
- A load calculation or clear explanation of how the size was chosen
- The furnace make, model, AFUE, and blower type in writing
- Permit and inspection included (required in Ontario)
- Removal and disposal of the old unit
- Commissioning — gas pressure set and temperature rise verified
- The warranty terms (parts and labour) spelled out
If a quote is a single number on a napkin with none of the above, keep looking.
Want a straight, no-pressure quote for your home? Alderwood Mechanical installs furnaces across Toronto and the GTA with upfront pricing and no contracts. Call 437-229-8618 — we answer 24/7.
Alderwood Mechanical serves Toronto, North York, Scarborough, Etobicoke, Mississauga, Vaughan, Markham, Oakville, and surrounding GTA. G1 licensed gas fitters. No contracts. Upfront pricing.
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