7-chamber window. The 2016/2017 innovation by JEZIERSKI MARKOWE OKNA in the category of window joinery. Ultra Passive is the best equipped window in the premium segment. It is not only the warmest window (up to 0.64 W/m2k for a reference window), but also the safest – its anti-burglary corner with a bayonet bar provides an increased level of burglary protection. Ultra Passive is a 7-chamber window with a 3-stage sealing system. It was specially designed for passive houses and fulfils all the requirements set by the German Institute for Window Technology (ift Rosenheim) for passive construction. The new system is equipped with the world’s first deformation-resistant EPDM weldable gasket (returning 85% to its original shape after 15 years).