My husband and I recently added a garage on to our home. We knew that we would have to insulate the garage door in order to keep heat from escaping from it. Because it is a two car garage, we had to buy two garage door insulation kits. One would not have been enough. Although one kit would have kept some heat from escaping, it would not have been an adequate amount of insulation. If you do not insulate properly, you may as well not insulate at all. You heating and cooling bills will not reflect any savings unless you use the proper amount of insulation.