(1)
At the outside design temperature, required heating facilities shall be capable of maintaining an indoor air temperature of not less than
(a)
22 ° C in all living spaces,
(b)
18 ° C in unfinished basements,
(c)
18°C in common service rooms, ancillary spaces and exits in houses with a secondary suite, and
(d)
15 ° C in heated crawl spaces.