No, building must be upgraded for at least one energy class, as stipulated in the Rulebook on the Energy Efficiency in Buildings ("Official Gazette of RS", No. 61/2011)) and the Rulebook on the conditions, content and manner of issuance of certificates of energy performance of buildings ("Official Gazette of RS", No. 69/2012), meaning that is firstly necessary to carry out Existing Situation and Study on Energy Consumption and then to examine whether the planned renovation measures lead to the fulfilment of this requirement. Also, all architectural elements that are being renovated, must meet the prescribed heat transfer coefficient for existing buildings.