Correction for coverage of window on Man J
So I was looking over a man J calc. They have all my W facing windows with the same multiplier. 3 of the windows are facing a covered porch - like 12 feet deep just a foot above the windows. I don't feel like I ever get direct sun on these windows and they act more like a North facing window from a cooling standpoint. They wind up being the same btu/hr/sqft as uncovered windows which clearly isn't right.
Is there a way of correcting this that I don't see? These windows add up to 5000 btu/hr despite being low-e.
There are just so many ways to fudge manual J's. Does anyone know about what a 10 sqft West facing low-e window (shgc of .3) equals in btu/hr in NC?