Originally Posted by DFW_M5
If you don't have spray foam walls or 6" walls filled with fiberglass bats and R38 in the attic, triple pane seems like putting a silver saddle on a mule.
Since OP seems to have their question answered, hopefully a little drift is OK...
I'm sure you are right, but does anyone have a good easy-to-read source on this? Windows make up only a fraction of surface area of a home, and while they obviously don't insulate as well as a typical wall/ceiling, does the difference in good/better/best windows really have much overall effect?
Seems like a fairly simple formula summing the conductance, taking into account the conductance values and area of each, then again with a delta for the windows. But I don't think I've ever seen this spelled out.