Taiwan is a mountainous island where buildings must withstand earthquakes and typhoons while also achieving energy efficiency. This case study looks at a university building in the town of Tainan and proposes small but critical improvements to increase energy efficiency that would not require drastic building renovations. We used readily available tools including eQUEST, thermal infrared cameras, and U-value testers to determine energy efficiency improvements. In addition, we considered the daily use of the building, its occupational schedule, and zones with and without air conditioning. We evaluated the lighting, insulation, window materials and window shading. Comparisons were then made between the baseline design and the actual building energy consumption data to improve the accuracy of the findings. Our results show that a 16% improvement in energy efficiency can be achieved by increasing the standard AC temperatures, changing the lighting as well as by modifying the windows and shading. While insulation is critical in cold weather environments, we determined it is a minor factor in hot, humid environments. Most methods used in this study are appropriate for homeowners and small businesses to identify the energy efficiency methods appropriate for their climate and houses.