Thermal performance of window glass and entire windows and doors system was simulated by WINDOW and THERM software. Combined with the annual climatic data from Hangzhou, annual building energy consumption with different energy saving windows and doors was calculated by DeST software. The results show that materials of windows and doors play a significant role in saving energy.Wooden profiles with low thermal conductivity and Low E glass can significantly reduce the heat transfer coefficient, while thicker aluminum profiles increase heat transfer coefficient. Energy saving windows and doors with different materials and types greatly influence the energy consumption derived from air conditioning in summer and heating in winter in Hangzhou, respectively. Local climatic conditions must be considered in the choice of energy saving windows and doors.