The market for highly energy-efficient buildings is expanding rapidly, and the demand for reliable high-performance components is growing. When the heat leakage in the buildings are evaluated, it is seen that 25-30% of the heat leakage occurs from windows and doors. PVC window / door profiles with higher thermal insulation properties which are produced with extrusion process, will provide energy efficiency in buildings and these windows are certified as “Passive House Component”. In this study, parameters on design of PVC window profile section has been simulated. PVC frame width and number of chambers are increased. With the help of these optimizations, window system is designed according to higher thermal insulation properties. Thermal transmittance value of window section was minimized. The Uframe and Uwindow values were measured as a 0.92 W/m²K and 0.78 W / m²K respectively, which allows Uw,mounting (in installation situation) lower then 0.85 W/m2K in an accredited laboratory. For each window and door systems, there are also required other performance criterias. Windows and doors should have good properties for air permeability, impact resistance(drop test), water tightness and wind load. For this system, window specimens were tested according to product standard EN 14351-1 in accredited laboratories. The results of performance characteristics for windows were defined as Air Permeability- Class 4, Resistance to Wind Load- Class C4 / B4 and Water Tightness –E1500, Impact resistance – Class 3. This system is entitled to Passive House Component Certificate.