The amount of sunshine illuminating the wall of the building can highly affect energy efficiency of building. Solar radiation striking the vertical wall which faces east is provided by formula
R = R 0 cos sin ,
where R 0 is maximum solar radiation possible, is angle which sun makes with horizontal, and is direction of sun in sky, with = 90o when sun is in east and = 0o when sun is in south. What percentage of R 0 is striking wall when is equal to 45o and sun is in southeast?