Recreational sports facilities are known to have a high level of energy consumption since the indoor-air conditions are crucial to athletes' performance. The thermal and moisture conditions are difficult to control without adequate models. A CFD model is used to simulate the thermal and moisture conditions of a gymnasium. This is coupled to a dynamic envelope model. Then, a reduced order model is developed to serve as the basis for an optimal energy control solution. Weather uncertainties are then evaluated within a dynamic control procedure that incorporates weather prediction errors at each time step.