To enhance energy-saving potential in the architectural design phase, this study explores the energy consumption drivers of a standard floor in a commercial complex in Chengdu We collected the energy consumption data during the cooling season and the operational timings of air conditioning systems across rooms with different orientations, and calculated the Energy Consumption Index (ECI), defined as the energy usage per hour per unit area of a room. Our findings revealed a distinct pattern in ECI during the cooling season, with west-facing rooms exhibiting the highest ECI, followed by east, south, and north orientations in descending order. We employed the DeST-C software to simulate a range of standard buildings, varying both in orientation and window-to-floor ratio. The simulations demonstrated that, when rooms share an identical structural configuration but differ only in orientation, the ECI during the cooling season follows to the same trend as previously observed. Moreover, when examining rooms with the same orientation but different in window-to-floor ratio, we found that an increase in window-to-floor ratio correlates positively with an elevation in ECI during the cooling season. These findings highlight the critical importance of considering building orientation and window-to-floor ratio as pivotal factors in designing energy-efficient structures.