The use of energy and the increase of the greenhouse effect are amongst the biggest problems of today’s society. In the European Union buildings present 40 % of the overall use of energy, which is why the Directive of the European parliament on the energy performance of buildings says, we have to make Energy Performance Certificate as instruments to achieve energy efficiency in buildings. Methodology includes temperature characteristics as well as other factors with increasingly important role, for instance heating and air conditioning systems, use of renewable energy, passive heating and cooling elements, shading, indoor air quality, adequate natural light and design of the building. The thesis deals with the methodology of measured and calculated energy certificates of a building as provided by current legislation in the cases of buildings of Dr. France Prešeren’s kindergarten. The first section presents the purpose of creating energy certificates, the legal basis and the adequacy of calculated and measured certificates for different objects. In the following part it analyses the results of measured and calculated energy performance certificate of each object and compares them to each other. It notifies on the necessary carefulness when comparing the two cards and analyses the energy efficiency of buildings depending on the maintenance, but at the same time it also alerts on other factors that influence energy consumption in buildings.