Ontario heating & cooling questions, answered

These are the heating-and-cooling questions GTA homeowners ask us most often. We've kept the answers short, honest, and specific to Ontario in 2026 — no upselling, no fluff. If your situation needs a real number, that comes from a free in-home estimate, not a webpage.

Are there rebates in Ontario for replacing air conditioning?

No — there's no rebate for replacing a standard air conditioner with another standard AC in Ontario. The current program, Home Renovation Savings (HRS), rebates heat pumps, not air conditioners.

Here's the angle worth knowing: a cold-climate heat pump cools your home in summer exactly like an AC, and also heats it in winter — and it qualifies for up to $7,500 through HRS. So a lot of homeowners who were just going to replace a dying AC instead upgrade to a heat pump and capture the rebate. The amount depends on your current heat source: gas-heated homes get roughly $500 per ton, while homes on electric, oil, or propane get the larger rebates (about $1,250 per ton).

What is the major disadvantage of a heat pump?

The main drawback is reduced heating capacity in extreme cold — as the temperature drops well below freezing, a heat pump pulls less heat from the outdoor air, so most Ontario installs pair a cold-climate heat pump with a backup (a gas furnace or electric heat) for the coldest stretches. The other common drawback is the higher up-front cost.

Modern cold-climate models are a different animal from the old units — many run down to roughly −25°C to −30°C. But capacity still tapers as it gets colder, and a heat pump is less forgiving of bad sizing or installation than a furnace. Done right, with the backup wired in correctly, you get efficient heating and cooling from one system most of the year.

Is geothermal worth it in Ontario?

Geothermal is worth it for the right home — it's the most efficient system you can buy and qualifies for up to $12,000 in HRS rebates — but the high up-front cost means it pays off fastest for homes currently heating with electricity, oil, or propane, for new builds, and for long-term owners.

A full install is a major investment and payback typically lands in the 7–15 year range, sooner for homes coming off expensive fuels and longer for a home already on cheap natural gas. The trade-off for that cost is longevity and very low operating cost: the ground loop can last decades, so you're buying years of cheap heating and cooling after it pays for itself. We'll tell you honestly whether it makes sense for your home before you spend a dollar.

What is the cheapest way to heat your house in Ontario?

For most Ontario homes that already have natural gas, a high-efficiency gas furnace is still the cheapest to run today. But a modern cold-climate heat pump is now genuinely competitive — and often cheaper overall once you factor in the HRS rebate and year-round efficiency, especially if you don't already have gas.

The clear losers on operating cost are electric baseboards and oil or propane heat — they're the most expensive to run. Those are exactly the homes where switching to a rebated heat pump pays off fastest and usually lowers the monthly bill. Bottom line: if you've got gas, gas is hard to beat month-to-month; if you're on electric, oil, or propane, a heat pump is usually both cheaper to run and the smarter long-term move.

What is the “4pm rule” on heating?

Straight answer: the “4pm rule” isn't an Ontario heating rule or anything technical — it's a UK money-saving tip about curtains. The idea is to open them during the day to let the sun warm the house, then close thermal curtains around 4 p.m. (UK sunset) to trap that heat and delay turning the furnace on.

The principle — closing insulated curtains at dusk to hold heat — helps any home, including in Ontario. But the specific “4pm” timing is British and doesn't map to our winters, and it has nothing to do with your thermostat or Ontario's time-of-use electricity hours. We'd rather tell you that plainly than dress it up as something it isn't.

What runs up your electric bill the most?

In a typical home, anything that makes heat is the biggest draw — space heating leads by a wide margin (around 64% of total household energy), followed by water heating and large appliances. Air conditioning spikes the summer bill but is a small share over a full year.

On the hydro bill specifically, the heavy hitters are electric furnaces or baseboards, the water heater, the clothes dryer, and the oven. One Ontario-specific lever: most homes are on time-of-use pricing, where on-peak electricity costs roughly double off-peak — so running laundry, the dishwasher, and EV charging in the evenings and on weekends meaningfully lowers the bill. And if you heat with electric baseboards, a heat pump is the single biggest move you can make to cut that cost.