In initial used building with EPS walls, the wall still contains a considerable amount of water that evaporates over time. In order to analyze the effect of moisture levels on a drying building energy performance, the heat and moisture coupling transfer of building wall with multilayer composition in the cold serious area Harbin, China, was simulated. The freezing of liquid moisture in exterior envelope was considered and the moisture content gradient was used as mass transfer driving forces. The effect of some impact factors, as initial moisture content, vapor retarder, interior wallpaper and exterior glazed brick on the wall energy consumption were also analyzed. It is concluded that the effect of drying are most significant during the first year of building initial use. The drying rate of the new building was significantly high in the first year, especially in the first few months. These changes during initial drying often account for a significant fraction of the overall load and have notable effect on the building energy performance. (c) 2008 Elsevier B.V. All rights reserved.