Unlike summer, solar admittance levels from the east and west-facing windows could very modest in winter. In contrast, north-facing windows play a major role in keeping the house warm in the wintertime.
In cold climate zones, it is recommended that the area of the north-facing windows be much greater than the west and east-facing windows. This helps reduce the artificial heating demand while having minimal effect on the need for artificial cooling in summer.
In the summertime, the sun is very high in the sky at mid-day; in the southern hemisphere, the sun is directed towards the north at mid-day. This suggests that although north-facing windows gain significant heat in winter, they cease to have a large effect on increasing the artificial cooling demand; hence, it is not wise to propose an adjustable shading device for north-facing windows; However, an optimized fixed horizontal shading always help with the energy demand in summer.
South-facing windows play no role in decreasing building’s heating demand.