Due to growing interest in the use of bifacial photovoltaic modules this paper analyzes the actual performance of an installation consisting of three types of modules, bifacial monocrystalline silicon among them. An analysis of the operation of the on-grid photovoltaic installation working in the warm summer continental climate of south-eastern Poland was carried out in 2021-2022. The roof-top installation with a rated power of 14.04 kWp, consisting of modules made of monocrystalline silicon (mono-Si), polycrystalline silicon (poly-Si) and monocrystalline silicon bifacial (bifacial-Si) delivered 936.76 kWh/kWp in 2021 year and 1070.94 kWh/kWp in 2022 year. In order to predict the optimal configuration of bifacial modules in the tested location, a simulation was performed in the PV-Syst v.7.4 program. Based on a comparison of numerous simulated variants, differing in the orientation of the modules and the reflectivity of the ground surface the best results were found for 1.5 m height above the roof level, 45˚ inclination angle and albedo coefficient of 0.8.