This paper presents an energy-saving control solution which has been developed for existing public buildings by designing an intelligent ICT-based service system for monitoring and controlling the environmental conditions. The proposed control strategy addresses the required infrastructure and implements the design to properly balance energy savings and comfort issues. In this work, a combination of occupancy detection and daylight harvesting is presented as input to the control algorithm. The implemented results presented here utilize the hardware and software on a pilot campus and achieve an average energy saving of 71% for three sample days during summer times. Simulation results are also presented for annual period and complete test case building.