While cooling load rules of thumb can provide a rough estimate of the cooling load, they have limitations. They do not take into account specific building characteristics, such as window orientation, shading, and insulation, which can significantly impact the cooling load. Additionally, they do not account for variations in occupancy, equipment, and lighting schedules. Therefore, it is recommended to use more detailed calculation methods, such as ASHRAE’s Cooling Load Calculation (CLC) method, for accurate HVAC design.