## 5 Results and Perspectives  
The results identified in the case study further highlight the need for a pre-study multicriterial analysis regarding the current state of the building alongside a heritage study. In situ studies of the building, conducted in a non-invasive way, have facilitated more in-depth knowledge of the building, thus making sure that the solutions proposed will extend the life cycle of the building. The solutions for energy reduction are presented in Table 6.  
The results of the simulations are summarized in Table 7. \begin{table}
\begin{tabular}{c c} \hline \hline
**Solution** & **Description** \\ \hline S1 & Keeping the wood frame with restoration measures but replacing the glass with a performant 4-12-4 type with low-e \\ S2 & The hydrothermal insulation solution for the attic floor will be made with a layer of fireproof \\ S3 & mineral wool of a minimum of 30 cm and a maximum conductivity of 0.04 W/mK \\ S3 & Replacing the interior lighting luminaires, which currently have fluorescent lamps, with efficient \\ LED lighting luminaires & \\ S4 & Installing thermostatic valves on all heating radiators \\ S5 & Mounting 25 kW solar photovoltaic panels on the west facade \\ S1 + S2 + S3 + S4 & Analysis of solutions 1–4 \\ S1 + S2 + S3 + S4 + S5 & Analysis of solutions 1–5–complete \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Proposed energy efficiency solutions. The energy efficiency solutions recommended for a building, including window upgrades and solar panel installation, have undergone comprehensive analysis to determine their individual and collective effects on energy usage. The initial solution (S1) entails enhancing the windows by installing high-performance glass, while preserving the original wooden frames. This approach results in a substantial 18.16% decrease in energy use, highlighting the crucial importance of window insulation in enhancing the overall energy efficiency of buildings, especially in historic buildings. The second method (S2) improves thermal insulation by installing fire-resistant mineral wool on the attic floor. This method decreases energy usage by 16.1%, thus lowering the amount of heat lost via the roof, which is a prevalent source of inefficiency in older structures. By enhancing the insulation of the roof, this solution improves the building's thermal envelope and helps maintain stable inside temperatures, resulting in a more comfortable life and work environment. The third solution (S3) centers on enhancing the lighting system by replacing outdated fluorescent lamps with energy-efficient LED luminaires. The change leads to a moderate reduction of 2.44% in overall energy consumption. However, it has a significant impact on the energy used just for lighting, which highlights the efficiency of LEDs in comparison to older lighting choices. The fourth solution (S4) incorporates thermostatic valves on all heating radiators, enhancing the heating system's efficiency by optimizing heat distribution management. This modification results in a 6.59% decrease in energy consumption, demonstrating the advantages of contemporary heating controls in minimizing needless heating and improving the comfort of occupants. The fifth option (S5) integrates renewable energy by installing 25 kW solar photovoltaic panels on the west facade. This not only reduces the building's dependence on external power sources by 4.24% but also promotes sustainability efforts by decreasing the carbon footprint linked to conventional energy sources.