Evaluation and possibilities of energy savings in the process of rehabilitation of residential buildings built before the Second World War

Improving the Serbian housing stock built before the beginning of World War II has the potential to achieve multiple benefits in terms of both saving energy and enhancing the quality of life in them. Considering the importance of preserving these buildings as testimonies of our architectural past, investing in their rehabilitation will also contribute to the preservation of a significant element of our national identity. Recent data from the 2011 Census show that 322,244 dwellings in Serbia were built prior to 1945, accounting for 10% of total dwellings. Nearly half of these (45%) are located in Vojvodina, and a fifth (20%) belongs to Belgrade area. The methodology for rehabilitation was based on the typology of buildings from this period, as the starting point for calculating the potential energy savings and was developed for the purpose of the National Typology of Residential Buildings in Serbia. The Serbian housing stock built before World War II is characterized by high diversity as to the territorial distribution of construction types, while the remarkable differences between the old urban and rural architecture further add to the complexity of the typology. Typological classification was made to: family and multi-family housing. While family houses were classified into freestanding and row houses, multi-family housing included multi-family houses and apartment blocks. Within this distribution, typical representatives of building types were recognized. Each of them was the subject of thermal calculations in three possible cases: a) the present state, b) the standard improvement and c) the advanced improvement of the building. Standard improvement measures implied application of common measures for energy refurbishment that are typical of the domestic market and that resulted with the improvement of building energy performance for at least one energy efficiency class. The advanced level of energy improvement included specific measures that contributed to the maximum possible improvement of the energy performance that was in accordance with the characteristics of the rehabilitated building. The present paper defines possible improvements to the selected building types as model representatives of real structures. The calculations of the energy performance and building type distributions were used to determine the potential energy savings in the process of rehabilitation