Eight Heat Pump Myths Ontario Homeowners Still Hear

Heat pumps have gone from a niche product to one of the most common questions we receive. Along the way, a lot of half-truths have built up, some too optimistic and some too pessimistic. Here are eight we hear often, and what the evidence actually says for Ontario homes.

Myth 1: "Heat pumps don't work in Canadian winters"

This was true of many older units. Today's cold-climate air-source heat pumps (ccASHPs) are designed to keep producing heat down to roughly −25 °C to −30 °C. What is true is that both their output and their efficiency drop as the outdoor temperature falls. On the coldest nights, a heat pump may need help from backup heat.

In southern Ontario, the vast majority of heating hours are well above −15 °C, so a properly sized ccASHP carries most of the season on its own. Colder regions such as Ottawa, Sudbury and Thunder Bay need more careful sizing and planning for backup. Our guide to heat pumps in Ontario winters goes into detail.

Myth 2: "A heat pump will always cut my heating bill"

Not necessarily. Since the federal carbon charge on natural gas was removed in April 2025, gas and heat pump heating cost roughly the same per unit of heat in many Ontario homes. A heat pump usually saves money compared with electric baseboard, oil or propane. Compared with gas, it can save a little, break even or cost a little more, depending on your gas and electricity prices and the heat pump's real-world efficiency. See one year without the carbon charge for the numbers.

Myth 3: "Heat pumps are always more expensive to run than gas"

This is the opposite error. With a seasonal coefficient of performance (COP) of about 2.5–3.0, which is typical in southern Ontario, a heat pump delivers 2.5–3 units of heat for each unit of electricity. On a favourable rate plan, or in a hybrid system that hands off to gas in the coldest weather, a heat pump can be cheaper to operate. Run your own numbers in our heat pump versus furnace calculator.

Myth 4: "I'll need all new ductwork"

Many homes with existing forced-air ducts can use them with a ducted heat pump. The contractor should check that the ducts can move enough air, because heat pumps often deliver air at lower temperatures and higher volumes than a gas furnace. Some homes need modest duct changes; few need a full replacement. Homes without ducts can use ductless mini-splits instead.

Myth 5: "Bigger is better, so it can handle the coldest day"

Oversizing is one of the most common installation problems. An oversized heat pump cycles on and off frequently, dehumidifies poorly in summer and can be less efficient. The right approach is a proper room-by-room heat loss calculation (often called a Manual J or equivalent CSA calculation), with the heat pump sized to match the home and backup heat covering the extreme cold. Ask every contractor how they sized the system. See our sizing guide.

Myth 6: "Turn it way down at night to save money"

With a gas furnace, a 2–3 °C overnight setback typically saves roughly 5–10% on heating. With a heat pump, deep setbacks can backfire. When the thermostat calls for a large temperature increase in the morning, many systems switch on electric resistance backup heat, which is much less efficient. Small setbacks of 1–2 °C, or none at all, usually work better. Smart thermostats designed for heat pumps can manage recovery more gently.

Myth 7: "If the backup heat comes on, something is wrong"

Auxiliary or backup heat is a normal part of most heat pump systems. It is expected to run during defrost cycles and in very cold weather. It becomes a concern if it runs often in mild weather, which can point to a sizing problem, a thermostat set-up issue or a fault. Ask your installer to show you how to tell when backup heat is running.

Myth 8: "I have to rip out my gas furnace"

You do not. A hybrid or dual-fuel system keeps the furnace and switches to it below a set outdoor temperature, often somewhere around −5 °C to −10 °C depending on prices. That can be a sensible first step, particularly if your furnace is relatively new. Read our guide to hybrid dual-fuel heating.

What actually matters most

In practice, the success of a heat pump in an Ontario home depends less on the brand and more on a few basics:

• A proper heat loss calculation and right-sized equipment.
• Equipment rated for cold climates, with a good HSPF2 rating.
• A thermostat set up correctly for the heat pump and any backup.
• An experienced, licensed installer. Refrigerant work requires an ODP certificate, and gas work requires a G1 or G2 licence.
• Reasonable insulation and air sealing, which reduce the heating load the system has to meet.

If you are considering a heat pump, the Home Renovation Savings Program may offer a rebate, but pre-installation approval is required. Confirm details on saveonenergy.ca (opens in a new tab).