Lawrence Berkeley National Laboratory

To curb the spiraling demand for building energy use, China's Ministry of Construction has worked at developing and implementing building energy standards, starting with a standard for heated residential buildings in the Cold regions in 1986, followed by a standard for residential buildings in the Hot Summer Cold Winter Region in central China in 2001. In July 2001, a similar effort was started to develop a standard for residential buildings in the Hot Summer Warm Winter Region, comprising of the entirety or large portions of Guangdong, Guangxi, Hainan and Fujian. The target for the standard is to improve the thermal efficiency of buildings by 50 percent compared to current construction, which are typically uninsulated and have single-pane windows. Because of the importance of controlling window solar gain, the standard developed tables specifying the required window thermal transmittance and shading coefficient for differing window-to-wall ratios. The intent of such trade-off table is to permit flexibility in the location and size of windows, as long as their thermal performances meet the requirements of the standard. For further flexibility, the standard provides three methods of compliance: (1) a simple set of prescriptive requirements, (2) a simplified performance calculation, and (3) a detailed computer-based performance calculation using a Custom Budget approach.