Refers to a previously published algorithm for calculating the fraction of a window shaded by a roof overhang or window awning. States the algorithm has been extended to include the case of shadows crossing the top edge of the window. A calculation of the portion of diffuse ground-reflected radiation incident on the window that is not blocked by the awning has been added. The computer program calculating the shading has been improved in several ways. Gives the updated equations and some sample results for a variety of awning and overhang geometries.

KEYWORDS: Algorithms, computer programs, calculating, shade, canopies, windows.