Globally, 50.44% of buildings are over 30 years old. Old buildings have problems such as obsolete safety monitoring systems and poor management efficiency caused by the use of old equipment. For the better management of buildings and their facilities, we developed an efficient management system based on digitized data from sensors in each device that is connected to the system. The system monitored the operation of each device in real time and sent messages to maintenance personnel in case of any abnormality in each device. This system ensured the normal operation of the building and saved costs and energy via efficient functions. The system was developed and implemented for one year. The operation outcome showed the completeness, relevance, standardization, and visualization of collected data and information. It also enabled the effective scheduling of operation and maintenance by querying the data from each device for intelligent building management.