I dont like wasting things either. I have improved my loft insulation, changed half the lights to lo-energy, and double-glazed all the windows. Frankly though, I find anything else is just too expensive to do.
Good for you, you’re not a waster wih a 1950s $3/bbl oil mentality. The operable, insulated, automatic-on-photocell window shutters available now are just too expensive, the cost/benefit ratio doesn’t work for the average homeowner on his own dime. And yet here is an opportunity for some major insulation manufacturer to develop mass produced units backed by public financial support, to cover vast numbers of energy-robbing window-holes in homes. Plus you can add insulation panels to walls, like thick, new siding; and “quilts” over roofs. Hey, it’s your own money you’re heating the cold night air with, why?