The building industry in China is energy-intensive, and promoting energy efficiency improvements and energy savings in this sector is of vital significance for its sustainable development. Using a proposed meta-frontier DEA approach, this paper investigates the key factors responsible for changes in the economy-wide energy efficiency and the sources of both energy inefficiency and energy-savings potential in China's regional building industry for the 2000-2014 period by considering three aspects: the technology gap, scale efficiency, and pure technical efficiency. The results show that (1) during the sample period, the energy efficiency in China's building industry increased significantly. Technological progress and improvements in pure technical efficiency were the two main contributors. (2) Energy inefficiency in China's building industry was measured at 0.5836, indicating that more than half of the current total energy consumption in this sector was wasteful. The regional technology gap and pure technical inefficiency were the two main sources of energy inefficiency. (3) Energy inefficiency and the energy-savings potential in China's building industry showed distinct spatial characteristics, indicating that the focus of future work should vary by province. (C) 2017 Elsevier Ltd. All rights reserved.