Triple Glazing Steel windows with optimum thermal break. Modern windows must meet a number of different demands and perform a variety of functions. They must save energy, be airtight and watertight, easy to use, meet structural requirements, but also be highly attractive. HI Passive House steel windows and fixed glazing feature isolators made from glass fibre- reinforced polyurethane and boast optimum thermal and structural properties, achieving UW values to 0.69 W/m2K= U-Value 0.12 Btu/ft2/h for fixed glazing and UW values to 0.8 W/m2K= U-Value 0.14 Btu/ft2/h for windows. With a basic depth of 90 mm, vent dimensions of up to 2800 mm and a vent weight of 180 kg are possible. Different infill unit thicknesses up to 67 mm can be used with triple glazing, but also with burglar-resistant or bullet-resistant glass. Due to the slimline external face width and the wide variety of coating options, HI Passive House steel windows can meet high thermal insulation requirements in terms of both function and design.