In most Dutch classrooms high draught risks result in insufficient ventilation and poor air quality in the heating season, while in the rest of the year the risk of overheating is high due to the high internal heat load. In this study a new ventilation concept is proposed, in which fresh air is supplied through perforations spread over the whole ceiling surface. As a first step, the performance of this ventilation concept was tested in a laboratory setting. The measurement results show that even at extreme conditions (11 dm3s-1 per child, DeltaT=18 K) comfort problems will not occur. During the heating season a pilot study was held in a classroom with children to evaluate the practical implementation of the concept in an existing school. The results show that with modest investment costs, extremely low fan energy consumption and a low noise level the indoor environment in classrooms may be improved considerably.