The refrigeration and air conditioning (AC) systems in a typical supermarket account for 70% and 10% of total energy consumption of store, respectively. Generally, it is difficult to find the optimal store temperature for minimizing the total energy consumption of both systems and customers’ comfortableness. This paper attempts to find the optimal set point through a developed control device installed in a typical supermarket. From the data acquisition system, the preliminary results show that the total energy consumption of both systems in 23℃ store temperature is lower than that of 25℃ store temperature by 10%, and total energy consumption of store can be save at least 5%. Since the store temperature cannot be decreased unlimitedly for consideration of customers’ comfortableness. The future work has been conducting to find the optimal set point in the supermarket by using our developed control device.