In this study, the optimal supply angle of the air curtain installed above a store entrance was reviewed via a transient CFD simulation to reduce heating and cooling energy consumption from opening doors during business hours. As a result of the simulation, when the air curtain is installed, the amount of infiltration is drastically reduced. During the summer season, it is advantageous to supply air angled towards the outdoor side rather than indoor side of an entrance door in cooling conditions, with an angle of 10°⃚ most effective for outdoor temperatures of 30℃, 33℃, and outdoor side 10°⃚ angle for outdoor temperatures of 36℃. In the winter season, it is more advantageous to supply air to indoor side rather than outdoor side of an entrance door in heating conditions and with an angle of 20°⃚ most effective for outdoor temperatures of -6℃, -9℃, and indoor side 10°⃚ angle for outdoor temperatures of – 12℃.