dymonite69
EcoClassic
Since most have walls and a roof then windows represent 40% - 60% of heat loss (or gain). So if you have 3x the insulation then you will reduce the 60% to 20% and save 40% on your heating or cooling.
If you have other primary research (non-commercial) data then feel free to share with us all.
I have, I did... check my other posts... it's physics, commercial or otherwise...