The development trend of modern architecture, the building energy efficiency have become an increasing attention, the paper outlines the importance of energy saving windows, creating a building model.DEST software using the windows energy simulation of the building model. According to the simulation results to make a number of technical measures for energy saving windows. Windows are an important part of the building, but also in building insulation weakest link, Its long-term energy consumption accounts for about 50% of building long-term energy consumption, so the insulation properties of windows increasingly widespread attention.Today in the building a social economy, good thermal insulation of windows is to improve the indoor thermal comfort, energy-saving one of the key areas, the study of energy saving windows is significant.