I've been reading through some of Mr. Money Mustache's old blog posts, and came across one about heating bills. In the comments below, someone mentioned a product from the Warm Company. I'm familiar with their quilt batting because I've used some of it in small art quilt products. They have something called "Warm Windows," complete with downloadable instructions. They are shades/curtains to keep your home better insulated.
Other than the OP on those comments (who might be reading this), has anyone else tried them? If so, have they made a difference? Did you do the sew or no-sew option?
Thanks!