The problem
Heat pumps get sold on the rebate and then disappoint for reasons that have nothing to do with the technology. Two mistakes account for most of it: sizing the outdoor unit from floor area instead of a heat-loss calculation, and leaving the controls at the installer's default so the system either hands over to backup heat far too early or grinds away in weather where it costs more to run than the gas furnace beside it. A unit picked from its headline rating at 8.3 °C can be short by a third of the capacity the house needs at −15 °C.
What we did
Capacity is chosen from the manufacturer's extended capacity table at the outdoor temperatures this climate delivers, not from the headline rating at 8.3 °C, because what matters is the output the unit still produces at −15 °C and at the design temperature. The outdoor section shown is mounted raised for winter drainage and defrost, on a pad or bracket that keeps the base pan clear of ice. The changeover point is set deliberately against the house and its fuel — for a dual-fuel setup that is the outdoor temperature where gas becomes cheaper per unit of heat — instead of being left at a factory default nobody revisits.
- Cold-climate air-source heat pump
- Matched indoor coil or air handler
- Raised mounting for winter operation
- Controls set for changeover
The result
Heating that carries the house through most of the season on the heat pump and hands over to backup only when the economics favour it. Current Ontario programs return up to $7,500 on qualifying installations, and the paperwork is filed as part of the job.
Is this your situation?
This kind of work is worth a conversation if any of these sound familiar:
- Your air conditioner is due for replacement anyway, which is the natural moment to consider a heat pump.
- You heat with electricity, oil or propane and want a lower running cost.
- You want to claim a current Ontario heat pump rebate on the installation.
- A previous quote sized the unit off floor area rather than a heat-loss calculation.
Questions about this kind of job
What makes a heat pump cold-climate rated?
A cold-climate unit uses a variable-speed inverter compressor and an enhanced vapour-injection or similar refrigerant circuit so it keeps a useful share of its rated capacity and an acceptable efficiency at −15 °C, and keeps operating well below that. Standard heat pumps lose most of their output near freezing. Manufacturers publish the capacity at each outdoor temperature, and that table, not the nameplate tonnage, is what sizing uses.
What is the changeover or balance point and who sets it?
The balance point is the outdoor temperature at which the heat pump's output equals the house's heat loss; below it the unit needs help. The economic changeover is the temperature where the backup fuel becomes cheaper per unit of heat delivered. On a dual-fuel system the thermostat's compressor lockout and auxiliary lockout are set to that temperature by the installer, using current gas and electricity rates rather than a default.
Does a heat pump replace the furnace or work with it?
Either. With electric backup the heat pump is the only heating system and needs an air handler with electric strip heat, and in some houses a larger electrical service. With a gas furnace kept as backup, called dual-fuel or hybrid, the heat pump covers most of the season and the furnace takes over below the changeover. Which is right depends on the electrical service, the age of the furnace and fuel prices.
Which rebate program applies to a heat pump in Ontario right now?
The current provincial program is the Home Renovation Savings Program run by Enbridge Gas and Save on Energy, launched in January 2025. The Canada Greener Homes Grant closed to new applicants in 2024, and the federal Oil to Heat Pump Affordability program applies only to oil-heated homes. Amounts, eligible equipment and installer requirements change, so check the program page before the quote is signed.