This paper investigates the ability of intermediate models such as zonal models to predict environmental conditions in a room. The first part compares experimental data to zonal and conventional k-å computational fluid dynamics model predictions in a mixed-ventilation room. Then, in order to investigate the impact of building material moisture adsorption and desorption processes on indoor air humidity and predict humidity distribution in a room, a zonal model was integrated with a building material moisture transfer model, based on the conservation of energy and dry air and water vapor mass. The model is applied to a room conditioned by a fan-coil unit. Our results suggest that this model is able to give a satisfactory prediction of transient humidity distribution in the room as well as to provide meaningful information on cooling loads.