The scope of this European Standard is to standardise the required inputs, the outputs and the links (structure) of the calculation method in order to achieve a common European calculation method. The energy performance may be assessed either by values of the heat emission system efficiency or by values of the increased space temperatures due to heat emission system inefficiencies. The method is based on an analysis of the following characteristics of a space heating emission system, including control: non-uniform space temperature distribution; heat emitters embedded in the building structure; control accuracy of the indoor temperature. The energy required by the emission system is calculated separately for thermal energy and electrical energy, in order to facilitate determination of the final energy and subsequently the corresponding primary energy according to other standards.