Dual Pane Windows for Cold Weather Camping

We tried the 3M product, and it was money wasted as it would not stay in place. We had plexiglass cut to size for all the windows in our 1984 Avion TT. We did that when we decided to spend a winter at 8500' in Granby CO. Temps were as low as 36 degrees below. We drilled holes for the window operators to go through the plexiglass. We drilled holes in the window frame so we could attach plastic tabs to hold the windows in place. We applied a narrow weather stripping to each window frame, that the plexiglass sealed against. It worked very well and kept our windows free of condensation as well as reducing heat loss. There were other measures we took to remain very comfortable and keep all systems functioning for 3 months. If I recall, we spent about $200.00 having a local shop cut all the windows. It was money well spent. We used them repeatedly on cold weather trips as they were easy to install and remove.