My opinion only..
If given the choice on RV double pane windows or not,I would pass..The reason is when doing most of my travels on mountain backroads the seals in the window failed on more than one occasion making for a foggy window just like a house double pane can do with a window shaker AC..
They used to make storm windows for all RV's which it seams they don't do anymore..I liked them and prefer them to double pane..
Maybe the double pane works for those that don't spend the majority of there time off road but they don't for me..I see little difference in summer or winter between the two mostly because of the use of reflectix in non used windows in extreme temps.