Solar heating systems in buildings have increasingly been studied in the past two decades. In several applications the primary energy demand is now for both heating and cooling, and modem solar collectors should be designed to provide climatization during the whole year. Solar systems are seldom applied in Europe, and large buildings, such as office buildings and schools, continue to be built with mechanical ventilation systems. The study presented in this paper is part of a European XVII Thermie project entitled "Pilot project for photovoltaic, energetic and biohousing retrieval in a school", whose aim was to install a photovoltaic plant and solar air collectors coupled with a sun breaker structure at a scientific high school in Umbertide, in central Italy. This paper describes the research and development activities concerning a solar air collector suited for winter heating and summer ventilation, which was installed at the high school. The collector physical and numerical modelling of heat transfer and fluid flow in winter operation is presented. The system performance has been estimated as a function of different parameters in order to provide a tool for the design process. Furthermore, the climate in the area has been simulated through the available experimental data, and the system behavior under these conditions is presented. The collectors were installed at the scientific high school in Umbertide in spring 2001. Summer ventilation cooling is under testing and an experimental test period is foreseen next winter to validate the design of the collectors and their performance. (C) 2002 Elsevier Science Ltd. All rights reserved.