The impact of building orientation on residential heating and cooling

Heating and cooling loads have been calculated for a prototype residential building at different orientations, using a development version of the building energy analysis computer program BLAST. The study was carried out for 25 climates in the United States. It was found that in all climates, when the more extensively glazed exposure is oriented to south, total loads are significantly lower than those in the same building oriented east or west. North orientation also produces lower total loads than east or west orientations in the southern two-thirds of the U.S., and roughly equivalent loads in the northern third. Total loads are higher for north than south orientation except in extreme southern latitudes of the U.S. (those areas with dominant cooling loads). Variation of peak loads in response to orientation and sensitivity of results to (1) total window area and its distribution, (2) size of window overhangs, and (3) level of thermal mass are reported.