Yes or no depending on you but, it is recommended to have the fan on when the air conditioning (AC) system is running. The fan helps distribute cool air throughout the room or building, and it also helps to improve the efficiency of the AC by evenly distributing the cool air. When the fan is set to the "auto" setting, it will turn off when the AC reaches its desired temperature, which can help save energy. Additionally, running the fan with the AC can also improve indoor air quality by circulating and filtering the air. In conclusion, having the fan on when the AC is running can help improve the performance and efficiency of the AC system, as well as create a more comfortable indoor environment.