In the master thesis we analysed the energy simulations and possible improvements in the energy efficiency of an existing multi-apartment building in Ljubljana using different computational tools and approaches. The aim of the master thesis was to investigate the possibility of using newer technologies, such as software in BIM environment and LiDAR camera, in sustainable building analysis. For this purpose, one method was used to calculate the building energy performance indicators and possible energy efficiency improvements of the building using input data obtained through field measurements using a laser meter and computer programs such as URSA 4.0 and PURES 3. The other method was to obtain input data using LiDAR images of the building and use of programs in the BIM environment such as Revit EnergyPlus and DesignBuilder. The results obtained by the two different methods were then compared with each other. We found that the results are comparable and that it is possible to produce an energy performance certificate for a building using a BIM model of the building modelled with LiDAR camera imagery. The master thesis proved that new technologies focused on energy efficiency in construction industry can be an excellent tool for experts involved in the analysis of sustainable building construction. In the future, it would make sense to explore directions and ways that would allow a greater implementation of the above-mentioned technologies in the Slovenian construction industry, especially in the field of integration of BIM technology with existing programs for the calculation of energy simulations of buildings.