Profiled steel cladding is a widely-used product in construction, and can be adapted to act as a building-integrated solar air heating collector. A mathematical model is presented of an air heating solar collector using profiled steel as the absorber and transparent multi-layer polycarbonate rigid sheeting as the cover. The model is validated by experiments conducted within a controlled laboratory environment, and th-experimental results are also presented. The expected full-scale performance has been evaluated based on the assumption that the proposed solar collector is to be used as an integral part of a building wall structure situated in an urban area of the UK in winter. The evaluation leads to equivalent values for U-L and for F-R Of approximately 4.0 W m(-2)degrees C-1 and 0.71, respectively, which provide an estimation of the performance of such a collector system in the UK.