ENERGY STAR® Qualification Criteria for Residential Doors
Many doors don't have any glass (like your front door), but even doors with lots of glass (like a sliding patio door) have lower glass-to-frame ratios than windows or skylights. This means doors can provide more insulation than a window or skylight can. Performance criteria for doors are based on the amount of glass they have (called glazing level) and rating cetified by the National Fenestration Rating Council (NFRC). Download this mini-guide to learn more about door specifications.
- Glazing levels