This paper describes the Mobile Architecture and Built Environment Laboratory (MABEL) and its application for systematic building performance evaluation for compliance testing, commissioning, strategic and operational facility management and continuous improvement in the built environment.The first part of the paper introduces the application areas of on-site building performance evaluation and discusses the shortcomings in this regard in current practice. It emphasises the need for on-site investigations to generate information on \u27as built performance\u27 for the \u27feedback\u27 loop between design, operation and occupancy of new buildings, retrofit or adjustment.The second part introduces the Energy-Comfort-Behaviour Framework for \u27across-the-board\u27 building evaluation and discusses MABEL\u27s role in this scheme. MABEL\u27s objectives, procedures and the performance measurement matrix are explained and discussed. <br /