For most Ontario homes replacing both a furnace and an air conditioner at once, a hybrid — cold-climate heat pump with the gas furnace kept as backup — is the choice that carries the least risk. A heat pump alone suits a tight, well-insulated house with a healthy electrical service. A gas furnace alone still makes sense if your existing furnace is only a few years old, or the house is large and leaky enough that heat loss outruns what a heat pump can deliver on a -20°C night.
Two numbers frame the decision. A high-efficiency gas furnace installs for $4,500–$6,500 in the GTA, while a 3-ton cold-climate heat pump lands at $9,500–$15,000 and replaces the air conditioner as well. Current Ontario rebates run $500–$7,500 depending on the system, and the top of that band is reserved for heat pumps — which is what narrows the gap.
Why the old answer to this question expired
A furnace makes heat by burning gas; a heat pump moves heat that is already in the outdoor air, which is why it can deliver more energy than it consumes. The technology that changed the Ontario answer is the variable-capacity inverter compressor, which holds usable output far colder than the single-speed units homeowners remember from the 1990s. Our cold-climate heat pump explainer covers the capacity curve in detail.
The second change is refrigerant. New residential equipment has moved off R-410A to A2L refrigerants such as R-32 and R-454B, so a heat pump bought today uses different service procedures than the air conditioner beside it. That matters when you compare quotes, because line sets and tooling are not interchangeable between the two.
Heat pump vs furnace, line by line
- Installed cost, 3-ton system — heat pump $9,500–$15,000 · high-efficiency gas furnace $4,500–$6,500 (air conditioning not included)
- Rebates — heat pumps take the top of the $500–$7,500 Ontario band · furnace-only upgrades typically see $500–$1,500, plus $75 for a smart thermostat
- What it replaces — heat pump covers heating and cooling in one outdoor unit · furnace heats only, so an air conditioner is a separate purchase
- Output on a cold night — heat pump holds most of its capacity into the -20s and leans on backup below that · furnace delivers full output at any outdoor temperature
- Supply air temperature — heat pump runs long cycles of roughly 30–40°C air · furnace delivers short bursts of 50°C-plus air, which is why the registers feel hotter
- Fuel — heat pump runs on the Ontario grid and its cost tracks your electricity plan · furnace burns natural gas billed by Enbridge
- Service life — heat pump roughly 12–18 years, running year-round · furnace 15–20 years, idle all summer
- Failure mode — heat pump loses capacity gradually as it ages · furnace tends to fail outright, usually on the coldest night of the year
Houses where a heat pump is the stronger buy
- A 2000s or newer build in Alton Village, Millcroft or River Oaks, where the envelope is tight and the ducts were sized for a modern blower
- Any home on electric baseboards, oil or propane, where you are paying resistance-heat or delivered-fuel prices today
- A house whose air conditioner has already failed, since one outdoor unit then covers both seasons instead of two
- A finished basement or addition that never had proper heating, where a ductless head solves the room and the whole-house question at once
Houses where a gas furnace still makes more sense
- A high-efficiency furnace installed within the last five years — the greenest system is usually the one already in the basement
- A pre-war brick house in Westdale or Old Oakville with single-pane windows and no wall insulation, where heat loss outruns the equipment
- A property with a 100 A service and no room in the panel, where the electrical upgrade would cost more than the fuel saving returns
- A rental or a house being sold within a couple of years, where the payback window never opens
Which ratings matter when you compare models
For an Ontario buyer, heating performance decides the purchase and cooling efficiency is the tiebreaker. Ask for the model's rated heating capacity at -15°C and at -25°C rather than a single headline efficiency number, and check that the model appears on the NEEP cold-climate list your installer is quoting from.
On the cooling side, ENERGY STAR for split central air conditioning requires at least 15.2 SEER2 (12.0 EER2), and the 2023 federal minimum sits below that — so an ENERGY STAR badge is the more meaningful filter. Our guide to SEER ratings for Ontario homeowners explains how the SEER2 test differs from the old SEER numbers on your current unit.
Free quotes, written pricing.
What happens to your bills when the fuel changes
A switch from gas to a heat pump moves cost from the Enbridge bill to the hydro bill, so the comparison only works if you look at both. Your electricity rate plan — Time-of-Use, Tiered or Ultra-Low Overnight — has a real effect, because a heat pump runs long cycles and can be scheduled to lean on the cheapest hours.
Pull 12 months of both bills before you commit and have the installer model against your actual usage, not a provincial average. Households heating with electric baseboards, oil or propane see the sharpest improvement, because a heat pump delivers several units of heat per unit of electricity where a resistance element delivers one.
What the house needs before a heat pump goes in
- Electrical capacity — an outdoor unit plus electric backup heat draws real amperage, and an older 100 A service may need an upgrade before the equipment can be sized properly
- Duct capacity — heat pumps move more air at a lower temperature, so undersized returns in a 1950s bungalow show up as noise and weak second-floor airflow
- Backup heat — a hybrid uses the gas furnace, an all-electric setup uses resistance strips. Ontario installs should have one or the other
- Outdoor clearance — the unit needs to sit clear of snow load and roof drip, and away from the neighbour's bedroom window
- Thermostat — dual-fuel control needs a thermostat that handles a switchover setpoint, not the builder-grade unit on the hall wall
How a hybrid decides which fuel to use
A dual-fuel control watches the outdoor temperature and hands heating to the furnace below a setpoint you choose, commonly somewhere between -10°C and -15°C. Above that line the heat pump carries the house, which covers the bulk of an Ontario heating season. Below it, the burners take over and you get full output for the handful of nights that need it.
The setpoint is adjustable, so the system can be tuned toward cost or toward carbon as rates change. It also means the furnace runs few enough hours that its remaining life stretches out — worth knowing if you are keeping a furnace that still has years left in it.
The verdict: a decision rule you can apply tonight
- Furnace under 10 years old and the air conditioner is dying — replace the AC, or add a heat pump as the cooling side and keep the furnace as backup
- Both units over 12 years old — price a hybrid first. The labour, sheet metal and permit overlap, and combined work typically runs $7,500–$11,500
- Heating with electric baseboards, oil or propane — a heat pump is the strongest case on this list, and the fuel savings do the heavy lifting
- Large, draughty house with a real heat-loss problem — fix the envelope first, then reassess. Insulation is cheaper than oversized equipment
- No natural gas at the property — heat pump with electric backup, sized against a heat-loss calculation rather than a square-foot rule
Get the numbers run for your own house
Every honest answer here depends on a heat-loss calculation, your duct capacity and your electrical service — three things nobody can assess over the phone. We quote heat pumps, furnaces and hybrids across Burlington, Oakville, Hamilton and the wider GTA, with written pricing before the work and the rebate paperwork filed by us.
See what a full changeover involves under heating services, or book a free assessment and we will tell you plainly which of the three options your house should be buying.
Frequently asked questions
Does a heat pump actually work at -20°C in Ontario?
A cold-climate model keeps producing useful heat well into the -20s, though its output drops as the temperature falls, which is why backup heat is part of the design. What matters is the capacity your specific model holds at -15°C and -25°C against your home's heat loss. Ask for those two numbers before you sign.
Can a heat pump go in without removing the furnace?
Yes, and that is what a hybrid or dual-fuel system is. The heat pump handles most of the season and the furnace takes over below a switchover setpoint. It is a common route for homes with a furnace that still has life left but an air conditioner at end of life.
Why does the air from a heat pump feel cooler?
A heat pump supplies roughly 30–40°C air over long cycles, while a gas furnace delivers 50°C-plus air in short bursts. Room temperature ends up the same or steadier, but the air at the register is closer to skin temperature so it does not feel hot. Most people stop noticing within a season.
Is a heat pump cheaper to run than natural gas in Ontario?
It depends on your electricity plan and how well the house holds heat, so the comparison has to be run on your own 12 months of gas and hydro bills. Homes heating with electric baseboards, oil or propane see the clearest savings. Gas-heated homes land closer, and a hybrid lets you use whichever fuel is cheaper that night.
Will a heat pump need a bigger electrical panel?
Sometimes. An outdoor unit plus electric backup heat draws meaningful amperage, and an older 100 A service can run out of room once a range, dryer and EV charger are counted. A load calculation during the quote answers it. A hybrid keeps the electrical demand lower because the furnace, not resistance heat, provides backup.