Effective evaluation on the thermal performance of envelope plays an important role towards the reduction of energy consumption for space cooling and heating. In order to calculate the energy consumption for cooling and heating and assess the whole energy efficiency of envelop designs, a new evaluation index on energy and thermal performance for office building envelop (EETPO) is put forward. Three cities of Shenyang, Wuhan and Guangzhou in China are selected for EETPO analysis, which represent the cold zone, hot summer cold winter zone and hot summer warm winter zone, respectively. The regression equations between EETPO and energy use for cooling/heating are studied in three cities, illustrations indicate that the regression lines fit extremely well and the algorithm is accurate and simple. According to the compulsory indices stipulated by standard (GB50189-2005), the maximum allowable values of EETPO are determined in three cities, the maximum EETPOc in cooling period is 1.750 W/m(3) K in Wuhan and 1.733 W/m(3) K in Guangzhou, the maximum EETPOh in heating period is 0.200 W/m(3) K in Shenyang and 0.414 W/m(3) K in Wuhan. This index and energy use calculation method can help designers to evaluate the whole energy and thermal performance of the proposed envelopes and analyze energy saving effects for different energy conservation measures. (C) 2014 Elsevier B.V. All rights reserved.