About thirty years ago, the old Early Winters company sold a product called the Proton Jacket. It had a very thin nylon outer layer, then a space blanket inside, with some mesh netting inside that to keep it off your skin. It was all sewn together, so there were lots of needleholes. As a simple windbreaker, it was pretty good. It didn't really breathe, so things tended to get sweaty inside.
Don't count on that reflected heat thing to do much.