63. For the purpose of section 61, the non-shaded area in winter of the glazing of a building with an open living space or of a building equipped with a central forced-air heating or ventilating system allowing for the distribution of the solar heat gain from such area, may be considered as 50% of the actual glazing area. Moreover, if the building is equipped with a cooling system, the glazing area used for calculation is considered as 50% of the actual glazing area unshaded in winter but shaded in summer.
For the purpose of this section, the glazing considered must be clear or have a shading coefficient higher than 0.70 and face a direction within 45 º of due South.
For the purpose of determining the non-shaded glazing area in winter, the shading must be calculated using the noon sun incident angle of 21 December.
Also, to determine the shaded glazing area in summer, the shading must be calculated using the noon sun incident angle of 21 June.
Moreover, the following may be considered as excluded from the calculation of the total glazing area:
(1) the glazed area of a building that is unshaded in winter and placed in front of any wall or floor made of materials designed to collect and store solar energy; and
(2) the area of a window equipped with a thermal insulating device allowing an increase in its thermal resistance of at least 0.8 m2 • °C/W in the absence of sunshine.
O.C. 89-83, s. 63; O.C. 1721-85, s. 10.