A method for controlling the temperature of the occupancy zone in a room equipped with a fan coil ispresented. The heterogeneity of the air velocity field and the temperature distribution is considered. As it leads to a system with a great number of differential equations, the Proper OrthogonalDecomposition is applied to build a low order model. Moreover, the value given by a sensor oftemperature enables the estimation of the temperature in the occupancy zone with a state estimator.The performances of the model are shown through the first results of simulation.