When installing a new garage door, many people forget about insulating it. In winter, frigid winds and heavy snow can make your garage feel like an ice box. Conversely, in the summer, un-insulated garage doors can turn the garage into a sauna. When installing a new garage door, it's vital to add insulation to protect against extreme cold and heat, block moisture, and save on energy bills. Follow these steps to insulate your garage quickly and easily.