Solar combisystems are solar heating installations providing space heating as well as domestic hot water for the inhabitants of the building. The energy sources are solar energy as well as an auxiliary source, gas or oil typically. This paper describes the advanced control strategy that enables the energetic optimization of the building and the combisystem as a whole. This strategy also aims at maximizing the degree of comfort in terms of temperature variation. It has been implemented on a solar combisystem manufactured in Switzerland. The strategy chosen is a predictive control strategy. It computes one-day optimal profiles for the flow-rate in the collector loop and for the power to be dissipated in the building. To do so, the dynamical models of the combisystem and of the building have been derived. Weather forecasts are also required to implement this predictive control strategy. The weather forecasts are provided on-line by the Swiss Meteorological Institute (SMI). To make this strategy robust with respect to modeling errors and discrepancies between weather forecasts and actual weather, a convenient closed-loop implementation of the optimal profiles has been developed. In addition to applying the optimal profiles computed for the flow rate in the collector loop and the power dissipated in the building, the tracking of optimal temperature profiles is also implemented. The proposed strategy has led to significant improvements in terms of energy savings and comfort and has proven to be very robust. It has been successfully implemented on a pilot plant and its commercialization is being carried out at the moment.