The main aim of the paper was to experimentally investigate the thermal performance of the newly developed concept of building integrated photovoltaics. The first experimental results were obtained for the two proposed techniques of direct integration of photovoltaic panels (PV) with an external thermal insulation composite system (ETICS). Both systems were developed, described in detail, and constructed on a south-oriented building wall, and the main novelty was the introduction of an additional layer with increased heat capacity in one of the variants. Components were equipped with temperature and heat flux sensors connected to the datalogger system. The measurement period was from July to December, while the temperature of the PV panels was measured and analysed. The results were statistically analysed, and the main differences were emphasized. Moreover, the advantages of the case with a higher mass were listed and recommendations were formulated. The obtained results of the possible temperature of exploitation allow one to determine the risk of damage or loss of performance.