The Ontario Building Code | Design Indoor Air Temperatures
6.2.1.2. design Indoor Air temperatures
(1) buildings classified as Group B, Division 2 or 3 occupancies or Group C residential occupancies that are intended for use in the winter months on a continuing basis shall be insulated and be equipped with heating facilities that are capable of maintaining an indoor air temperature of 22°C at the outside winter design temperature referred to in Article 6.2.1.7.
(2) All other buildings intended for occupancy in the winter months on a continuing basis should be insulated and shall be equipped with heating facilities to maintain a minimum indoor air temperature of 18°C or commensurate with the use of the building at the outside winter design temperature described in Article 6.2.1.7.
In Plain Language
Buildings classified as Group B care/detention occupancies or Group C residential occupancies used for continuous occupancy must be designed to maintain specific indoor air temperatures, addressing the comfort and health needs of occupants who spend extended time there.
This is a plain-language summary of the 2012/2017 Ontario Building Code text above, for general understanding only and not a substitute for the Code. Always confirm current requirements against the 2024 edition (O.Reg. 163/24) or a qualified professional before construction.