They do. A garage with a closed door acts like an air gap, meaning you get some extra insulation for free. It’s far from perfect, as the garage door itself can’t have particularly thick insulation, and the interface between the door and the frame is difficult to seal completely. Still, even an uninsulated garage with a closed door will typically be a bit warmer than the outside in the winter.
They do. A garage with a closed door acts like an air gap, meaning you get some extra insulation for free. It’s far from perfect, as the garage door itself can’t have particularly thick insulation, and the interface between the door and the frame is difficult to seal completely. Still, even an uninsulated garage with a closed door will typically be a bit warmer than the outside in the winter.