22-Jun-2014 04:51 PM
Since the sun rises in the East, crosses over the horizon on the South and sets in the West, you want your collector to face as much to the South as possible. To get the best results, your system needs the most sun it can get.
In most areas, a solar collector can face anywhere from East to West (its orientation) without losing more than 5% of the energy it would have produced if it were facing directly South. Exceptions include Easterly facing systems in areas with a lot of morning fog and clear afternoons where South facing or West facing would be much better. The opposite can be true if sunny mornings are very often followed by rainy afternoons.