When does the heat have to come on? Toronto's heating rules, explained
Toronto landlords must keep rental units at 21°C or warmer from October 1 to May 15 — the dates changed in 2025. Here's what the rules cover, what changes in 2026, and what to do if your unit is cold.
The short answer: in Toronto, landlords must keep every rental unit at a minimum air temperature of 21°C between October 1 and May 15. That's the City's Heating Bylaw, and it applies whether or not the building has "turned the heat on" for the season.
Worth knowing: these dates changed in 2025. The heating season used to run September 15 to June 1, and a lot of pages online still say so. The current window is October 1 – May 15 — what changed is the calendar, not the temperature: 21°C is still the floor.
What the rule actually requires
- 21°C is a minimum, measured in the unit. If your apartment is 17°C in January, it doesn't matter that the boiler is technically running — the landlord is offside.
- It's about temperature, not equipment. The obligation is the outcome. Radiators, forced air, baseboards — the City doesn't care how, only that the unit hits 21°C.
- Outside the dates, judgement applies. In a warm October or May, buildings can leave the heat off as long as units stay at temperature. In a cold snap outside the season, the property-standards expectation of a habitable unit still applies.
What about air conditioning?
The same framework now has a summer half: where a landlord provides air conditioning, it must run June 1 to September 30 and keep the unit at or below 26°C. And starting June 1, 2026, apartment buildings in the RentSafeTO program that don't have A/C in every unit must keep an indoor amenity space at or below 26°C through the summer — part of the same update that renames the Heating Bylaw the Indoor Temperature Standards Bylaw. We covered the cooling side in Ontario's new cooling rules.
Outside Toronto
Ontario doesn't set one province-wide heating date. Each municipality sets its own bylaw (dates and minimums vary), and everywhere the Residential Tenancies Act requires landlords to provide heat as a vital service. If you're outside Toronto, check your city's property-standards bylaw for the exact dates — but 20–21°C minimums are the norm.
If your unit is cold
- Measure and document. Note the indoor temperature, with dates and photos of the thermometer. A pattern beats a single cold morning.
- Ask in writing. A dated written request to the landlord starts the record.
- Escalate to 311. If nothing changes, a service request brings a City inspector, and a unit below 21°C in season can become a property-standards order — a documented, public instruction to fix it.
Check your building's track record
A landlord who ignored heat complaints before is more likely to do it again. Look up your building's outstanding orders & violations and its bylaw investigations — heat and vital-service issues show up in both. For apartment buildings, the RentSafeTO report card shows how the building scores on maintenance overall. Start with the property snapshot for everything at once, and turn on monitoring so a new order on your building lands in your inbox before the temperature drops.