The panel door system meets the requirements of even the most demanding users. The door can be used in single-family and multi-family houses as well as in public buildings. The panel door construction is based on the three-chamber AC-77HI system, in which an innovative thermal break is used for new doors. It eliminated the adverse effect of thermal stresses caused by temperature differences on the outer and inner surfaces of the door. The door is designed so that it is possible to make the door leaf flushed with the frame from the outside (the leaf profile is invisible from the outside). As door filling, commercially available one-sided overlay panels are used. The possibility of using hidden hinges increases the aesthetics of the door finish.