With the development of economy, building energy consumption increases rapidly. This paper used a commercial building in Shenzhen as a case study to analyze the factors influencing air conditioning energy consumption in commercial buildings and proposed recommendations for reducing building energy consumption. After analyzing the real-time data collected by the Internet of Things (IoT), it was found that there are significant differences in energy consumption among shops of the same type on the same floor (Shop 1, Shop 3, Shop 8). Comparison of the floor plan revealed that these high-energy-consuming shops are situated in the corner areas of the building. Using the DeST energy simulation software to model the building’s energy consumption, it was found that the solar radiant heat density and outdoor temperature have a significant impact on air conditioning energy consumption. This paper proposed replacing the existing glass with low-e glass, and energy consumption simulations based on this recommendation showed significant improvements in the results. This provides some ideas for reducing the operating cost of commercial buildings.