I have not tried it yet, but I am going to this winter for sure.
I read an article somewhere, I do not recall-maybe Mother Earth News, where you take a spray bottle of water, and bubble wrap (you know, for like securing fragile packages for shipping) to cover the windows.
Do it from the inside, pre-cut the wrap to the size of the pane of glass. Spray the water on the pane and then place the bubble rap with the bubbles sticking in, the flat back sticking on the pane.
In the article it says if the plastic falls off over time, you only need to re-wet it with spray and re-stick it. Easy clean up, sounds like.
Now, if it works, how do I resist the temptation, stronger in my kids, from popping the bubbles every time I walk by -