This paper presents a dynamic thermal model based on TRNSYS, for a building with an integrated ventilated PV facade/solar air collector system. The building model developed has been validated against experimental data from a 6.5 m high PV facade on the Mataro Library near Barcelona. Preheating of the ventilation air within the facade is through incident solar radiation heating of the PV elements and subsequent heat transmission to the air within the ventilation gap. The warmed air can be used for building heating in winter. Modelled and measured air temperatures are found to be in good agreement. The heating and cooling loads for the building with and without such a ventilated facade have been calculated and the impact of climatic variations on the performance such buildings has also been investigated. It was found that the cooling loads are marginally higher with the PV facade for all locations considered, whereas the impact of the facade on the heating load depends critically on location.