The Passive solar rule of thumb says to face the building South. Well, what if a view of a 160 acre pond is directly East? This was a tough one but not unusual. We ended up facing the building 45% off direct South which will give us a view of the pond from all of the rooms. This trade-off will cost us passive and active solar gain but will give us an incredible view.
Based on our location in New Hampshire it looks like 45 degrees off true south reduces annual active solar output by about 12% compared to facing directly south. However, in the winter months, it is reduced by about 17% (including Nov - Feb).