The building sector is the largest individual consumer of energy, and the only possible way for the systematic reduction of energy in this sector is energy renovation of existing buildings and construction of energy efficient buildings. In terms of energy efficiency, a building envelope has the greatest impact on the quality of the building. Measures proposed to improve building envelope quality aim to reduce the amount of consumed energy and also to reduce energy costs. During the process of implementation of measures to improve the building envelope, it is necessary to comply with existing legislation. This paper gives a review of the Technical regulation on energy economy and heat retention in buildings and the Ordinance on energy audits of construction works and energy certification of buildings. In all calculations recommendation given in those regulations were complied. This paper analyses the current state of the building selected among the complex of 12 buildings in the settlement of Sjenjak in Osijek. Evaluation showed that this is an energyinefficient building, energy rating is E. Based on this, measures with associated implementation costs were proposed to increase energy efficiency. An energy renewal project that was proposed in this paper which is also applicable to other similar buildings in this settlement.