## 4 Discussion
### Energy Use  
Energy consumption is one of the most pressing concerns today, and it requires a thorough understanding of the consumption patterns for each building. The primary factor that generates these patterns is a building's destination and usage. Educational buildingsexhibit distinct patterns due to the repetitive structure of the academic year, facilitating smarter and more efficient management of their energy consumption. To manage a comparison between several buildings, performance indicators such as energy use intensity and energy performance index can be used. The EUI is dependent on the total annual energy consumption, which varies based on several criteria, including geographical position, building design, occupancy and usage, and operational hours. These factors influence the EUI and should be considered in any comparative analysis [58]. The building under consideration has a primary function as an educational facility and is situated in Eastern Europe. An analysis of its EUI can be effectively benchmarked against similar educational structures in other European countries, allowing for a comprehensive evaluation of its energy performance relative to the regional standards. In certain European countries, the EUI for educational buildings ranges from 65 to 225 kWh/m\({}^{2}\)/year [59; 60; 61; 62; 63; 64]. The EUI of this educational facility, calculated at 90.19 kWh/m\({}^{2}\)/year, is below the average but still falls within this established range. This indicates that while the building demonstrates a commendable level of energy efficiency, there remains potential for further optimization. While the EUI calculated for this building aligns with the values observed in various European countries, it is notably lower when compared to the statistics from the United States (U.S.). In the U.S., the national median site EUI for university educational buildings is reported at 84.3 kBtu/ft\({}^{2}\)/year, equivalent to approximately 265.94 kWh/m\({}^{2}\)/year. Furthermore, the national median source EUI for the same category is significantly higher, at 180.6 kBtu/ft\({}^{2}\)/year, which translates into around 569.74 kWh/m\({}^{2}\)/year [65]. This disparity highlights the comparatively efficient energy performance of this educational building relative to its U.S. counterparts. However, the EUI values for different educational campuses can vary markedly, spanning from 61.3 to 731.09 kBtu/ft\({}^{2}\)/year. This considerable range is largely influenced by geographical factors, including climate, regional energy sources, and architectural styles [66]. Such variability underscores the importance of contextualizing energy performance metrics within the specific environmental and operational conditions of each campus. One potential factor contributing to this discrepancy is that the case study building features an air conditioning system exclusively within one amphitheater. This limited use of air conditioning significantly reduces its overall electricity consumption compared to buildings that are fully air-conditioned, further supporting its lower EUI. This highlights the impact of specific HVAC configurations on the energy performance across different educational facilities. Another relevant metric is the energy performance index, which is frequently utilized in India to assess energy efficiency [67]. The EPI value for the building under study is approximately 75.16 kWh/m\({}^{2}\)/year, positioning it within the average range as indicated by recent studies [50; 67]. This places the building's energy performance in a favorable context, suggesting that it meets acceptable standards for energy efficiency in educational settings. In Romania, according to the national Methodology for Calculating the Energy Performance of Buildings [68], the source EUI for refurbished educational buildings in the specific climate zone of the studied building is 82.7 kWh/m\({}^{2}\)/year. For the building in question, the source EUI calculated for the academic year is approximately 113.77 kWh/m\({}^{2}\)/year.