Curbly

You have to clean before applying the double sided tape!  Especially with exterior windows they can be dirty, making the tape loose grip and letting cold air in (or worse, the plastic falling off).  Don't skip the cleaning!

Average savings is around $30-40 per window per season if they are the older wooden frame type up here in Maine.

I have a book from the Canadian government (Canada knows cold), and it cautions against sealing on the OUTSIDE because that can trap moisture inside, and it can go in the walls. They say it's better to do INDOOR sealing to allow moisture to escape.

I don't think the shrink-wrap kind that you use the hair-dryer kind work any better; it's just that they might look a little smoother, since the hair dryer takes out any creases or wrinkles. To be honest, I've tried both and I think the stretch-kind look just fine and are much quicker to put up.

@how-to-videos - No, I have no stats, but as you can see from the video, our living room windows are huge; and in the years when I've been too lazy to plastic-wrap them, you can definitely tell the difference (you feel the drafts)

@jennifer: not sure what you mean? Are you asking about the ones where you have to use a hair dryer to shrink up the plastic?

What about the shrink wrap kind of window covering? Is that any better or worse or just more work?

Do you have any stats on how much you actually save from doing this? I am going to try it on my house now

Thanks!