This standard specifies the assumptions, boundary conditions and validation tests for a calculation procedure for the annual energy use for space heating and cooling of a building (or of a part of it) where the calculations are done on an hourly basis. The standard does not impose any specific numerical technique for the calculation of the room heating or cooling load and the internal temperatures of a room. The purpose of this standard is to validate calculation methods used to: describe the energy performance of each room of a building; provide energy data to be used as interface with system performance analysis )HVAC, lighting, domestic hot water, etc). It describes the assumptions, boundary conditions and validation tests for calculation methods intended to be used in compliance with this Standard. The validation procedure is used to check the energy use for space heating and cooling based on a transient sensible heat balance model, taking into account: the external surface heat balance the conduction through the building envelope the internal surface heat balance the air heat balance the heat balance solution method All other aspects are given either by prescribed boundary conditions or by input data and are not part of the model validation. It is assumed that prescriptive calculation models have to be used according to existing European standards. The system performance analysis and moisture balance are not within the scope of this standard.