Users of BEMS systems need to have performance information independent of that which manufacturers supply. Describes an assessment method developed because of this need. The method was implemented by using a building and equipment emulator developed within the framework of Annex 17 of the International Energy Agency. The chosen assessment procedure consists of specifying the functions required of the building energy management system. Manufacturers whose systems must be tested are then supplied with these specifications. They configure the system and connect it to the emulator. A series of tests during which the BEMS controls the modelled installation is then conducted, and an assessment report is written. Provides a description of the building and equipment emulator used, a description of the assessment procedure, and the results of tests already performed on two different BEMS used for managing hydronic heating systems in an office building. Possible use of these test results to compare the BEMS is discussed.KEYWORDS: energy management, controls, emulation, estimating, calculating, testing.