Furnace cost calculator
Pick a furnace type, your home size and the extras your job needs to see a typical Ontario installed price, itemized. A standard single-stage gas furnace replacement usually costs $4,000 to $6,500 before HST.
Estimate your furnace price
Estimates update as you change the inputs. Nothing is sent anywhere.
Estimated installed price
Before 13% HST
Your estimate
Typical single-stage range, before HST
Midpoint
- Single-stage furnace, installed$4,400 to $5,750
- New venting or chimney liner+$300 to $1,500
- Condensate pump+$150 to $350
- Ductwork modifications+$500 to $3,000+
- New thermostat+$150 to $600
- Municipal permit+$75 to $300
- Gas line work+$300 to $1,200
- 13% HST
For this home size the furnace itself sits at $4,400 to $5,750, inside the $4,000 to $6,500 typical single-stage range.
Homes over 3,000 sq ft, or with zoning, an addition or a second furnace, can price above the typical range.
Ductwork is open-ended: extensive changes can cost more than the high end shown.
Get the real number for your home: a free, no-obligation quote.
Planning estimate for a standard gas furnace replacement in a detached Ontario home with usable ductwork and gas service, not a quote. Furnace size should come from a CSA F280 load calculation, and an in-home visit sets the real price.
On this page
How the estimate is built
The calculator starts from the typical Ontario installed range for the furnace type you pick, the same ranges as our furnace price guide and the Ontario Furnace Prices index. Home size then narrows it: a small bungalow needs a smaller furnace and less time on site, so it lands toward the low end, and a large two-storey lands toward the high end. Size never pushes the furnace price outside the range for its type. Each extra you tick adds its own typical low and high. To check a quote, match the furnace type and the extras listed on it, and tick HST if the quote includes tax.
| Finished living area | Single-stage | Two-stage | Modulating |
|---|---|---|---|
| Under 1,000 sq ft | $4,000 to $5,400 | $5,500 to $6,900 | $7,000 to $9,200 |
| 1,000 to 2,000 sq ft | $4,400 to $5,750 | $5,900 to $7,250 | $7,600 to $9,800 |
| 2,000 to 3,000 sq ft | $4,900 to $6,250 | $6,400 to $7,750 | $8,400 to $10,600 |
| Over 3,000 sq ft | $5,250 to $6,500 | $6,750 to $8,000 | $9,000 to $11,000 |
Full typical ranges: single-stage $4,000 to $6,500, two-stage $5,500 to $8,000, modulating $7,000 to $11,000.
What the estimate assumes
- Replacing a gas furnace in a detached home with gas service and usable ductwork
- Equipment, labour, start-up and removal of the old furnace (often included; check the quote)
- Before 13% HST unless ticked, at typical Ontario prices reviewed October 2026
Why staging moves the price more than size
The furnace type is the biggest driver. A single-stage furnace is fully on or off. A two-stage furnace adds a lower setting for mild days and usually an efficient ECM blower. A modulating furnace adjusts its flame in small steps with a variable-speed blower, so it costs the most and heats most evenly. Most Ontario heating hours are far milder than the coldest night, which is why those lower settings matter.
One size up within the same furnace line is a modest step in equipment cost; a large house costs more mainly for the work around the furnace. The furnace size calculator estimates your size, and the best furnace brands guide covers brand tiers.
The extras, and when you need them
Extras are where quotes for the same furnace drift apart. These are the six the calculator prices; furnace installation cost covers the full job line by line.
- New venting or chimney linerAn old mid-efficiency furnace usually vents into the chimney; a high-efficiency one needs plastic pipes through a wall or roof. A gas water heater left in the chimney may need a liner.$300 to $1,500
- Condensate pumpHigh-efficiency furnaces make water. A pump is needed when no floor drain is close by.$150 to $350
- Ductwork modificationsAdapting the plenum is routine. New returns or resized trunk lines cost more, and this item is open-ended.$500 to $3,000+
- New thermostatA two-stage thermostat makes full use of the low fire. Some modulating furnaces need the maker's own control.$150 to $600
- Municipal permitRules differ between municipalities; your installer should know them and pull the permit.$75 to $300
- Gas line workA moved furnace or undersized pipe can mean new pipe, a shut-off valve and a sediment trap.$300 to $1,200
Worked example
A 1,700 sq ft detached home from the 1980s is replacing a 22-year-old mid-efficiency furnace that vents into the chimney. The owners choose a two-stage furnace and a thermostat that can run both stages.
| Line | Typical cost |
|---|---|
| Two-stage furnace, installed | $5,900 to $7,250 |
| New venting or chimney liner | +$300 to $1,500 |
| New thermostat | +$150 to $600 |
| Total before HST | $6,350 to $9,350 |
| Total with 13% HST | $7,180 to $10,570 |
The midpoint is $7,850 before tax. A quote well above $9,350 is not necessarily wrong, but ask for a line-by-line explanation: a premium brand, extra duct work or a hard-to-reach furnace room are the usual reasons.
Check your estimate against a real quote
A participating local heating and cooling company can visit, measure the home and give you a written price to hold up against this range.
Free, no obligation. About a minute to request.
Where this calculator stops
It does not size the furnace: ask for a CSA F280 load calculation. It assumes gas is already at the house, so oil, propane or electric conversions cost more. Attic or crawlspace furnaces and very large or zoned homes can run past the range. For other systems, use the heat pump cost calculator or see furnace and AC prices, and if you are weighing a monthly contract, read rent or buy a furnace.
Questions to ask before you sign
- Is the price before or after HST?
- What size is the furnace in BTU/h input, and how did you work it out?
- Does the price include venting, the condensate drain, the permit and haul-away?
- If my water heater stays in the chimney, does it need a liner?
Questions people ask
How accurate is this furnace cost calculator?
It shows the typical range for a standard replacement, not your exact price. Most straightforward swaps in Ontario fall inside the canonical ranges it uses, and the home size setting narrows that further. The gaps come from what it cannot see: the vent route, duct condition, access to the furnace room, the brand and the season you book.
Does a furnace replacement price include removing the old furnace?
Usually, yes. Removal and disposal of the old furnace is often part of the installed price in Ontario, but not always. Ask for it to be written on the quote, along with the permit, venting changes and the condensate drain, so that two quotes cover the same work and you are comparing like with like.
Is there a rebate for a new gas furnace in Ontario?
Under Home Renovation Savings, a standalone gas furnace is not a heat pump rebate measure (program terms checked October 4, 2026), and heat pump rebates there need approval before installation. Programs change, so confirm on the program terms page before you buy. Our Ontario rebates guide explains what is available.