Most standard steel cellar doors have minimal insulation (R-1 to R-3). Insulated doors available with R-values up to R-8.
Standard doors: Single steel panel, minimal thermal resistance
Insulated options: Foam core, weatherstripping, thermal breaks
Benefits: Reduced heat loss, condensation control, energy savings
For basements used as living space, insulated doors recommended. EcoSpect offers insulated Steelway options.