Changes in lighting load density affect not only energy use for electric lighting but also energy requirements for space heating and cooling. In general, a reduction in electric energy use would tend to increase space heating during the winter months and lower the cooling requirement in the summer. The implications for total building energy use, however, would vary, depending on the building and building services designs, its operation and the prevailing climates. This paper presents an analysis of the interactions between lighting and space heating/cooling loads in office buildings in the five major climatic zones-severe cold, cold, hot summer and cold winter, mild, and hot summer and warm winter-in China through building energy simulation using DOE-2.1E. (c) 2005 Elsevier Ltd. All rights reserved.