3M Crystaline Window film vs Double Pane Windows

Dual and triple pane windows in homes have an air gap of roughly 1/2 inch in order to provide meaningful insulation. Dual pane windows for RVs do NOT have enough air gap to provide anything close to the same. Their nothing but hype and a way to get more money out of a buyer. Better to use film if you want to see through them and cut Mylar bubble insulation (two layer is best) to fit your windows if you want max. insulation. Cost you a whole heck of a lot less!