This report describes the development and verification of a simulation of the dynamic characteristics of a room, a fan coil heating system, and a proportional thermostatic control system. The form of the model of each element in the system is determined on the basis of the physical characteristics of the element. An experimental investigation was accomplished to provide parameter values and to verify the model. The parameters in the models are based on manufacturers specifications, physical characteristics, and the experimental response. Many of the model parameters have been optimized to match the response of the model of a particular element to the experimental response. The simulation of the feedback control system which results from the interconnection of the models of the individual elements matches the response of the experimental facility to a high degree. The simulation provides the basis for more extensive simulations and for the analysis of the effect on energy consumption of the dynamic characteristics of the system.