The article presents research results obtained from bifacial and monofacial monocrystalline photovoltaic (PV) modules. The power changes were performed for different tilt angles 25° and 90°. The aim of experimental work was also monitoring of external factors as: temperature of PV module, wind velocity, intensity of solar radiation and reflectivity of surface under the PV modules. The computational simulation was applied for identification of PV system power balance changes for bifacial photovoltaic modules installed on roof with different black and white surface. The measured data were collected from solar invertors FRONIUS IG. The intensity of solar radiation was measured by pyranometer CMP 11 and wind velocity was detected by anemometer A100R. The results are presented as graphical relations. All measured data were statistically processed and for the data comparison was applied correlation analysis. Graphical dependencies showed that the power balance is better for PV system integrated into building façade from October to January. The bifacial PV modules had better power balance than the monofacial and their energy production strongly depends on reflection coefficient of roof surface material.