The Ontario Building Code | Warm-Air Supply Outlets
220.127.116.11. Warm-Air Supply outlets
(2) Except as provided in Sentence (3), when a room described in Sentence (1) is located adjacent to exterior walls, such outlets shall be located so as to bathe at least one exterior wall or window with warm air, except in bathrooms, utility rooms or kitchens, where this may not be practical.
(a) designed for this purpose, and
(b) installed with diffusers.
(4) At least one warm-air supply outlet shall be provided for each 40 m² of floor surface area in unfinished basements serving dwelling units, located so as to provide adequate distribution of warm air throughout the basement.
(5) At least one warm-air supply outlet shall be provided for each 80 m2 of floor surface area in heated crawl spaces serving dwelling units, and it shall be located so as to provide adequate distribution of warm-air throughout the crawl space.
(6) Except for pipeless furnaces and floor furnaces, the capacity of warm-air supply outlets serving dwelling units shall be not less than the design heat loss from the area served and shall not exceed 3 kW per outlet.
(9) Warm-air supply outlets located in finished areas shall be provided with diffusers and adjustable openings="http://thehandyforce.com/windows/" title ="Window installer in Toronto">openings and shall not be located on a furnace plenum.