© 2021 Elsevier LtdThe present work numerically investigated the energy performance of ten different glazing configurations in the severe cold climate of China. Furthermore, the thermal behavior of the glass windows filled with silica aerogel or PCM was analyzed and compared with traditional glass windows filled with air. In addition, to ensure the efficient functioning and minimize the heat loss through the PCM-filled window in the severe cold climate, three configurations of the triple-glazing selected for optimization and filled with silica aerogel and PCM were evaluated based on optical properties of the glass, thickness of the silica aerogel layer and melting point of the PCM. The transient solution for the simplified models of glazing units also included the radiative heat transfer. The results show that adding PCM into the glass window results in degradation of thermal performance of glass windows in winter. However, as the silica aerogel is used together with a PCM having a suitable melting temperature in triple pane windows, the thermal comfort can be improved. On the other hand, setting appropriate optical parameters of the glass for the radiation above 2.5 μm significantly enhances the energy efficiency of the glass window coupled with the silica aerogel and PCM.