I do a lot of "camping" out of my passenger van and I use a Mr. Buddy heater plus dog & blankets; it does generate moisture towards the rear passenger side window when I place the heater at center of van (extended van). Usually I turn it on during that brief time in the morning between waking up and getting up, dressing warm and good blankets help but it's just that period of time before really moving around that I need some heat in the van. For the windows I use UltraTouch pads, available at Home Depot or such store in rolls, cut them to size, make some pad sleeves from sailing fabric and put some velcro or snap buttons (your choice) to mount them that way you can still enjoy the view and stay insulated. This is the link to the UltraTouch with radiant barrier as some come without it and in different thicknesses: https://www.homedepot.com/p/UltraTou...-100661257-_-N
That's an interesting idea and looks like it would insulate well. Do the fibers soak up moisture? I find that on cold mornings, there can be enough condensation on the windows that it will run off, unless I have insulated the window well enough. Does this stuff stay dry?
Sailrite is awesome! It was the only place I could find YKK zippers sold by the foot when I was making the door screens for our van. And at a reasonable price too. They have tons of instructional videos on awning construction, zipper installs, etc. that were very helpful for me.