Assessing the Energy Renovation Impact on Public Building Performance: A Case Study of The Faculty of Natural Sciences and Mathematics in Banja Luka

<p>Buildings in Bosnia and Herzegovina are among the largest energy consumers, and deep energy renovation is a key pathway to reducing consumption and costs. This paper presents a case study of an educational building in Banja Luka, renovated in 2016 through envelope improvements and optimization of the heating system. Energy bills from 2013–2015 and 2022 were analyzed, and an energy audit evaluated the corresponding conditions (design values), which were then compared with actual consumption based on the energy bills. Total energy savings amounted to 94.18 kWh/m², or 74.96%, while economic savings reached 28.56%. The renovation also replaced coal as the heating medium with biomass, improving energy efficiency and supporting decarbonization goals. This study contributes by providing data on final energy use for heating in educational and cultural buildings, thereby supporting future improvements to national energy efficiency regulations.</p>