I've got 6 large windows in a hallway that I'm sure aren't so modern (some of them have leaked). Was considering a few layers of clear plastic, spaced evenly (1/4" apart) and stretched over a wooden frame, which I will screw onto the existing frame in winters.
I know first hand that plastering newspaper over old windows helped magnificently when I was painting once in my old house, but I don't want to do that this time for the whole winter.
Seeing clearly through them is not important.
Thanks for any ideas,
Dean