A Certain Slant of Light

by Andrea Millar — April 20, 2008

Did you know that energy-efficient buildings have an optimal orientation? The best sun-catching is done by structures with a longer east-west axis. Environmental construction news site has it all diagrammed for you on their primer "How the Sun's Path Can Inform Design." As the Web site points out, "using sunlight when it's needed and deflecting its power when it's not are two of the most important tasks in building design."

Throughout history, many buildings--pyramids, cathedrals, mosques--were built according to directional specifications. While suburbia appears to have phased out much of that design consideration, a solar energy revolution may well mean building according to ordinal demarcations such as distance from the equator and which hemisphere you're operating from. The technical aspects grow from there, ranging from finding the proper length of an overhang to the coatings for the variously located windows. Is the location optimal for solar, visual, or thermal transmittance?

The effects of wide-spread use of these building principles could be more radical than first appears. Where does something like a high rise fit in the solar energy equation? All those glass windows seem like a terrible thing to squander, but in many urban areas, priority is given to roads, landmarks, and other buildings. Maybe the green collar workers will be able to figure this one out for widespread applicability.