3M makes a great product. We use it to cover our windows. After questionable installation to begin with, and twenty years of use, you can feel the cold air coming through around the window frames. The kit consists of double stick tape and the clear film. You put the tape around the window frame, attach the film, then use a blow dryer on hot to shrink the plastic to the window. Works like a charm!
Heh...considering my window frames...that may not work. But I think I’ll check for it just the same! That must be what my sister-in-law was talking about.