What type of garage door is the most insulated?

The most insulated garage door is a three-layer steel sandwich door with polyurethane foam injected between the panels, reaching R-values of 18 to 20. The Raynor Innovations Centura, Clopay Canyon Ridge with Intellicore, and Wayne Dalton 9800 all sit at the top of the residential R-value charts. Polyurethane outperforms polystyrene foam at the same thickness, fills every cavity in the panel, and adds rigidity. For maximum thermal performance, look for 2-inch-thick panels with thermal breaks at the section joints and dual-flap weather seals at the bottom and sides. Glass and aluminum doors, even with insulated glass, top out around R-4 to R-6, far below insulated steel. For heated workshops, attached garages, or rooms above the garage, three-layer polyurethane steel is the clear winner.