The door insert from Masonite has a LOW-E Argon rating which means that that during the cold winter months, the glazing will allow the sun rays to filter through, to let in the heat and the light in. It will also limit interior heat to escape outside. During warmer seasons, the glazing will prevent the heat generated by the various heat sources from entering the inside, while allowing the light to enter. The insert measures 22'' (55.88 cm) x 36'' (91.44 cm) x 4'' (10.16 cm). This product is backed by a 10-year limited warranty.