Capability is not the same obligation
Section 36.1: "Every dwelling shall be provided with an approved heating system capable of maintaining a room temperature of 20°C at 1.5 m (4 ft 11 in) above floor level and 1 m (3 ft 4 in) from exterior walls in all habitable rooms, bathrooms and washrooms."
The obligation attaches to the equipment. A municipality that says "capable of maintaining" is regulating what is installed; one that says heat "shall be provided and maintained at" a temperature between two dates is regulating what the air is actually doing on a given morning. Barrie is the former.
Section 36.2 closes the gap you would expect: the system "shall be maintained in good working condition so as to be capable of heating the dwelling safely to the required standard". A boiler that once met the standard and no longer does is a breach.
Section 36.3 adds that no room heater shall be placed so as to cause a fire hazard.
What that means when a tenant is cold
A Barrie tenant whose unit is cold cannot point at a municipal temperature-and-date rule the way a Toronto or Oshawa tenant can, because the bylaw does not contain one.
That does not leave them without a remedy, and it does not leave you without an obligation. Section 20 of the Residential Tenancies Act still requires the unit to be in a good state of repair and fit for habitation, and section 21 still protects heat as a vital service. Those are provincial, and they apply in Barrie exactly as they apply everywhere else in Ontario.
The practical difference is the enforcement route. Where a municipal temperature rule exists, a tenant can call the city and get an officer. In Barrie the argument is more likely to run through the Landlord and Tenant Board, which is slower — and which makes your dated maintenance record the thing that decides it.