Window Quilts

Here's my new project
http://www.manytracks.com/Homesteading/winquilt
Our house is soooooooooooo cold in the wintertime. It just doesn't get above 65 and that's with the furnace running all day. Our windows are terrible. I think these would be perfect. My plan is to get huge quilts at the D.I. for $5 and cut them to fit and sandwich them between cute fabric. It won't be perfect but it should help us be warmer. I wonder if you can sew mylar emergency blankets inside the window quilt.