The article explores ways to improve the energy efficiency of historic buildings by adding insulation to their walls. The researchers studied different methods of internal insulation to prevent moisture problems. They found that using water-repellent treatments is crucial to protect the building's structure. Additionally, combining insulation with smart vapor barriers can help maintain the integrity of the walls. By using simulation tools, they were able to assess the risk of wood decay in critical areas like wooden beam-ends. Overall, the study shows that careful insulation choices are essential for preserving historic buildings while improving their energy performance.