Following the guidance set by the Directive on the energy performance of buildings (recast) (EPBD2), current regulations in Serbia which refer to the issue of energy efficiency and energy certification of buildings provides an opportunity of certification of selected unit of a building, such as a dwelling. This measure was set in order to make it possible for owners or tenants of the building or the building unit to assess and compare its energy performance. From the user’s perspective this measure is very important since, apart from reviewing the quality or the deficiencies of space in which they live, it would be an important parameter of economic evaluation of the apartment in the future. As energy performance of the apartment is not a priori identical to that of the whole building, the paper will analyze and compare these values for different positions in a horizontal and vertical plan of the same apartment within the building. Comparison of the results obtained for individual dwellings and for a building as a whole, will provide insight into the extent to which the disposition and the orientation of the apartment affect its energy performance.