Energy efficient measure to upgrade a multistory residential in a nZEB

Developing nearly Zero Energy Buildings (nZEB) represents a path toward sustainable communities as required by the Energy Performance of Building Directive (EPBD). As consequence, nZEB target for new or existing buildings has become a mandatory priority for the multidisciplinary researchers involved in architectural engineering and building physics. Therefore, it is grown the interest in design energy efficient measures for reaching the nZEB status of both new and existing buildings. In this paper, the energy efficient measures adopted for reaching the nearly Zero Energy Building standards, for a multi-floor residential building located in the Mediterranean area, are presented. The extra cost necessary to reach the nZEB target have been calculated in the case of the energy retrofit of an existing building (scenario 1) and in the case to directly realize a building with achieve the nZEB status (scenario 2). Further, the two scenarios have been compared under financial point of view. The results of this paper provide to builders and stakeholder useful information for quantify the convenience to build a nZEB building in advance in order to prevent the additional expenses necessary by future energy retrofit programs.