This paper presents the physical models for the maximum potential thermal energy savings from optimizing the hot deck and cold deck reset schedules for dual duct variable air volume systems. The maximum potential savings can be determined by using these models combined with basic system operating parameters and bin data. The system performance can be evaluated by comparing the actual savings with the maximum potential savings. The energy savings from optimal cold deck and hot deck reset schedules in multi-zone buildings should be at least 75 percent of the maximum potential savings.