Inicio Windows + Doors™ | Steel Systems are a streamlined, clean design, offering superior thermal insulation. The profiles are made of 1.5mm cold rolled tubular steel. Our product has flush and overlapping aesthetics with no visible corner welds, an efficient polyamide insulating core, and a profile design that accommodates the latest selective insulating glass. Our steel windows allow for a variety of glazing packages, using dual and triple glazing to customize your thermal performance.