This paper discusses a method of control for active, closed loop solar thermal systems with weather forecast integration. The solar thermal system of The S.KYBLUE House will be modeled; the model will be used with weather forecast data to predict energy collection with different modes of system operation; and the optimum operation mode will be implemented by the control. A Visual Basic program will be used to model and control the system. The Solar Rating and Certification Corporation's performance equation will be used to model the evacuated tube heat pipe solar thermal collectors. The model will be verified with The S.KYBLUE House solar thermal system and the system will be used to implement and evaluate the control strategy.