The purpose of this study was to analyze the need of adopting thermal environment code meeting comfort zone in public buildings. The thermal environment in public buildings was analyzed for this study. Furthermore, occupant"s thermal comfort and work efficiency were measured through qualitative and quantitative evaluation before and after the implementation of the system. In addition, the usage of individual heating and cooling appliances were analyzed for the additional increase in energy consumption. As a result, the study showed that occupants" thermal comfort and work efficiency were declined after the implementation of the system. Due to reduced thermal comfort, the use of individual heating and cooling appliances increases. Therefore, it needs to improve thermal environment code in public buildings.