Approaches for Complex and Integrated Refurbishment to Improve Energy Efficiency and Spatial Comfort of the Existing Post-War Mass Housing Stock in Serbia

The research presents approaches to the complex refurbishment of multi-family buildings constructed during the mass construction period in Serbia. These buildings comprise a quarter of Serbia’s housing stock, are characterized by high energy consumption for heating, and have major spatial and organizational deficiencies: small apartments, outdated and inflexible spatial organization, and the absence of elevators. The subject of the research is the application of the methodology of complex and integrated refurbishment by adding volume to existing multi-family buildings with the goal of achieving higher energy efficiency while remodeling and modernizing residential units and improving vertical building communications. The research presents a comparative analysis of the energy performance and spatial organization of the existing building and three variants of building improvement: Case 1 (without volumetric additions), Case 2 (with volumetric additions—relocating vertical communications), and Case 3 (with volumetric additions—expanding usable living space). Based on the Knaufterm simulations, the energy savings for heating energy consumption compared to the existing state are 81% in Case 1, 89% in Case 2, and 87% in Case 3. Based on predefined parameters of spatial comfort, a comparative analysis of spatial comfort in residential units was conducted for all three improvement variants.