I'm not usually interested in energy conversation/usage, but the space-age material called 'aerogel' seems really exciting. From what I gather it's currently around twice as good at insulation than Polyurethane and 4x better than Polystyrene (although in theory could be much better). However, apparently the price is around 2-3 times higher for the same amount of insulation. I'm most interested for it to be used as relatively thin wallpaper. However, I have a question. There's something I recently got for my windows that looks like cling film. You put it over the frame of the window, creating an air pocket in between, and then hairdryer it out to remove the creases. Only one layer is usually used, but I created two layers of the film (2 air pockets) and it's like having triple glazing now. Anyway, my question: Why can't wallpaper use this same principal, simply create many layers (say 1-2mm apart of thin plastic), and just fill it with air? Perhaps supported by tiny rods every other square cm to minimise conduction. Surely this would create better insulation than solid material alone? And yes, approximately as good as as the aerogel wallpaper as I mentioned earlier, except potentially HUNDREDS of times cheaper......... Does this idea stand up to the laws of physics?