In my thesis, I study energetic restoration of a thermally uninsulated building Hartnerjeva vila on Grajska street 2 in Murska Sobota. Through fieldwork, I capture the current status of the object, its geometry and how it is preserved. In the energetic restoration of this historically protected building, I include thermal insulation of the outer layer of the building, replacement of doors and windows with transparent elements, improvement of ventilation as well as an increase of the efficiency of its systems. Firstly, I calculate thermal characteristics of each construction compound with the computer program TEDI. Secondly, I study the sun exposure of the building. In accordance with the regulations (Pravilnik o učinkoviti rabi energije v stavbah PURES 2010), I make calculations for the thermal balance of buildings in 9 different ways with the computer program TOST. At first, I do not consider thermal bridges; subsequently, I calculate them in a simplified manner; and lastly, using the SIST EN ISO 14683 standard. I compare the results and analyze the energetic balance of the building. The study has shown that the heat loss in the existing building is too high. From all of my cases, my last one managed to reduce the yearly energy consumption for heating by three and a half times. Because of thermal bridges the energy consumption increased, but not more than 28 %. The minimum effect of thermal bridges is shown by the starting status using the simplified manner of consideration of thermal bridges.