I’ve learned that double poly-inflated sheets do have significantly better insulation than single poly because of that infalted air gap, but I’m not sure if it’s insulation is quite as good as the polycarbonate. As I said it’s SIGNIFICANTLY cheaper and much easier to install and more forgiving if your greenhouse is not installed perfectly level or square (the polycarbonate sheets need a perfect perfect structure to fit correctly). I’m leaning towards the double poly inflated because it’s so much