Water film solar collectors are asphalt and roof surfaces used as solar heat absorbers° Research into this field was started in 1983 at WREL, Luleå University of Technology. The performance of the collector has been studied by modelling of field tests which have been carried out.During the summer of 1987 the water film solar collector has been tested in a solar energy system° The collector consisted of a sheet-metal roof surface and the extracted solar heat was used for charging of a borehole heat store. During the test period measurements of climatic data and heat output were made° In this paper the technical feasibility of the energy system is discussed and some of the test data are presented.