It weighs hardly anything, the wire only adds ounces to the thin light liner. You could build it into the jacket, but the Idea is to have the wires as close to you as possable. 80 watts is not enough power to heat the air (convection) it is more of conductive heat, conducting the heat to your skin. Think of a 75 watt liht bulb. It gets hot, but all the heat is confined to a small area. This system has the heat spread out over about 6 square feet.