Abstract
The aim of this study is to develop a universal method for the unequivocal selection of the optimal combination of components determining the energy efficiency of buildings by means of an introduced global building energy consumption indicator. The basis of this method is a multi-criteria optimization of the components influencing the energy efficiency of buildings. The method requires the development of a detailed description of the set of components influencing the energy efficiency of buildings and the definition of the analysis criteria. The following analysis criteria were adopted: relative annual demand for final energy, cost, durability, and investment outlays payback time. The normalized values of these criteria are calculated in relation to the structure of a reference building. The proposed method makes it possible to explicitly indicate the most advantageous solution from the point of view of the weighted share of the individual criteria. The verification of the method was presented on the basis of the thermo modernization case study analysis for the adopted reference building. As a result, the most advantageous variant of modernization was determined, defined by the lowest value of the global building energy consumption indicator. A high effectiveness of the proposed method has been shown in relation to both the selection of the modernization option and the assessment of the individual component share in each modernization solution.