One of the most significant barriers for achieving the goal of substantially improving energy efficiency of buildings is the lack of knowledge about the factors determining the real energy use. There is often a significant discrepancy between the designed and the real total energy use in buildings, in which a complex array of factors play a significant role, including the user/occupant behavior. The reasons for this discrepancy are generally poorly understood, and often have more to do with the role of human behavior than the building design. For that, the IEA/ECBCS/Annex entitled as "Total Energy use in Buildings -Analysis and evaluation methods-" was initiated in the November 2009 and started on first of January, 2010 as working phase. The ultimate outcome of this annex is to strengthen the robust prediction of energy usage in buildings, thus enabling the proper assessment of short- and long-term energy measures, policies, and technologies. This paper deals with Annex 53 research works, present status and expected outcomes.