When Landlords Must Turn On Heat in Ontario: Minimum Temperatures by City

Ontario Has a Provincial Heating Floor, but Your City Sets the Real Number

Here is the part that trips up almost every landlord. Ontario does have a province-wide minimum: under O. Reg. 516/06, heat is a vital service from September 1 to June 15, and a rental unit must be kept to at least 20°C during that period.

But most landlords are held to a higher municipal standard layered on top. Your city sets its own minimum temperature (Toronto requires 21°C), its own heating-season dates, and its own fines. So you need to know both: the 20°C provincial floor, and your city's bylaw.

What does this mean for you? Don't stop at "the province says 20°C." Look up your city's property standards bylaw too. If you own properties in two cities, you may have two different sets of rules on top of the provincial floor.

When Do Apartment Buildings and Houses Actually Turn the Heat On?

Not on a fixed date, and this is the single most misread part of the rule. Both the provincial regulation and the municipal bylaws set a minimum temperature the unit has to hold. Neither one orders you to fire the boiler or the furnace on a particular morning.

That distinction matters most in a building on central heat. A boiler cannot be brought up and balanced in an afternoon, so the date an operator chooses to start the system is a scheduling decision made backwards from the obligation, not the obligation itself. The legal test is the temperature in the unit, measured the way the regulation says to measure it, and a building that is still comfortably warm in late September is not in breach because the boiler is cold.

Toronto spells it out. Chapter 497 says that "where a dwelling unit is at a minimum air temperature of 21 degrees Celsius, a landlord is not required to operate a heating unit." A warm first week of October is not a violation. A cold one with no working furnace is.

The province has a second exception, and it is narrower than it looks. Under O. Reg. 516/06 s. 4(3), the 20°C standard does not apply to a unit "in which the tenant can regulate the temperature and a minimum temperature of 20 degrees Celsius can be maintained by the primary source of heat." Read the wording carefully: it lifts subsection (2) only, which is the 20°C number. It does not touch subsection (1), so heat is still a vital service from September 1 to June 15 and you still have to supply it.

More important, no municipal bylaw carries an equivalent exception. Chapter 497 binds a Toronto landlord to 21°C from October 1 to May 15 with one carve-out only, the one quoted above, that the unit is already at 21°C. A tenant-controlled thermostat does not get you out of it. If you own in Toronto and your tenant runs their own heat, you are still the one a bylaw officer writes the work order to.

What no exception forgives is broken equipment. In a house rental that means the furnace, and in an apartment building it means the boiler and the distribution, which is the harder case: one failed circulator can leave a whole riser cold while the rest of the building reads fine. Book the service in August, not in January when every HVAC tech in the province is booked and charging emergency rates.

The Toronto Heating Bylaw

Toronto is the city landlords ask about most. Its 21°C matches what several other Ontario cities require, but Toronto is one of the few that pins the season to specific dates in a published chapter rather than leaving it to a general property standards bylaw, which is why it is worth reading directly. The rule lives in Municipal Code Chapter 497, renamed the Indoor Temperature Standards Bylaw as of June 1, 2026. Expect to keep seeing the old name, since most write-ups still use it.

The operative line: "Landlord shall ensure that a minimum air temperature of 21 degrees Celsius is maintained in all areas of the dwelling unit from October 1 in each year to May 15 in the following year." The City applies it where heating is provided at the property owner's expense.

Two things fall out of that for a Toronto landlord. First, the bylaw window opens a month after the provincial one, so September is governed by the 20°C provincial floor alone and you are still on the hook for it. Second, the bylaw closes on May 15 while the province runs to June 15, so the last month of spring is provincial territory again. The safe operating assumption in Toronto is 21°C from October through mid May, and never below 20°C from September through mid June.

The rename matters because the same chapter now carries the summer half too: where the owner provides air conditioning, it has to be operated from June 1 to September 30 to hold a maximum of 26°C. That is a maintenance duty on equipment you already supply, not an order to install AC. The full city-by-city version of that rule is in our cooling and air-conditioning guide.

Heating Rules by City

Here are the heating requirements for Ontario's major municipalities. If your city isn't listed, contact your local bylaw office or search your city's name plus "property standards bylaw heating."

Who Is Responsible for Heat?

This depends on who controls the heating system and what your lease says.

Even when the tenant pays for gas, you're still responsible for maintaining the equipment. A broken furnace is a maintenance issue under the RTA. The tenant can file a T6 if you don't fix it.

When Can You Turn Off the Heat?

Only after the heating season ends. Period.

The safest answer is mid-June: the provincial vital-service rule keeps heat mandatory through June 15. Toronto's 21°C bylaw window ends May 15. Ottawa sets its minimums by time of day instead, so confirm with your own municipality whether its bylaw has an end date at all. Until the date that applies to you arrives, the heating system must stay operational and capable of maintaining the minimum temperature.

Here's where landlords get into trouble: it's April 20, it's 25°C outside, and they shut the boiler down to save on gas. Then a cold snap hits three days later and the building drops to 16°C overnight. Now you've got a bylaw violation and angry tenants calling 311.

Note the difference between running the system and keeping it available. As the section above explains, nothing obliges you to burn gas on a warm day, and Toronto says so in terms. What the calendar governs is availability: until the season ends, the system stays serviced, connected and able to reach the minimum on the night the temperature drops. Decommissioning it in April is the breach, not leaving it idle.

What Happens If You Don't Comply

You can get hit from two directions at once. That's the part most landlords don't realize.

Municipal Bylaw Enforcement

When a tenant calls 311, a bylaw officer shows up with a thermometer. If your building is below the minimum temperature, you get a work order. You'll have a deadline to fix it. If you don't comply with the work order, fines follow.

In Toronto, fines can reach up to $100,000 for corporations and $50,000 for individuals. Other cities have their own fine schedules, but none of them are cheap.

LTB: The T6 Application

On top of the municipal fine, your tenant can file a T6 maintenance application at the Landlord and Tenant Board. If the Board finds you failed to maintain the rental unit (and inadequate heat counts), they can order a rent abatement. That's money back to the tenant for every day they froze.

So yes, it's possible to get fined by the city and ordered to pay rent abatement by the LTB. Double jeopardy? Not technically, but it sure feels like it.

Heating vs Cooling: The Full Picture

Ontario now has temperature rules for both winter and summer. Here's how they compare:

For whether AC is mandatory and the real 26°C city rules, read our Ontario cooling and air-conditioning guide.

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