The three chamber system for doors with thermal insulation. The system has a coplanar structure profiles (notch clearance 18 mm) and possibility of applying glazing beads for the “euro” standard groove. Profiled thermal breaks of width of 34 mm are applied in PE 78N. Specially designed compatible profiles enable the ease of connection between door and windows. The structural depth for frames and sashes equals 78mm. The system allows using a wide range of hardware and door locks. PE 78N allows to make kneaded, as well as screwed corners connection. What is more, there can be applied the variety of threshold solutions (also PVC one) to guarantee the best water and thermal insulation.