South Korea aims to reduce greenhouse gas (GHG) emissions by 40% by 2030 and over 80% by 2050, with buildings accounting for a significant portion of emissions. Aging structures, comprising 41% of the nation's buildings, suffer from poor insulation, increasing energy consumption and emissions. This study proposes a drone-based method using thermal imaging cameras to assess building insulation performance. Drones efficiently inspect large and high-rise buildings, ensuring consistent data collection. Using advanced software like Agisoft Metashape, thermal images are precisely mapped onto 3D mesh models, addressing issues of inconsistency in traditional methods. By transitioning from analog to digital techniques, this framework enhances accuracy, visualizes energy loss, and supports sustainable building management. The approach contributes to achieving national carbon neutrality goals and provides a scalable solution for reducing building-related GHG emissions.