This paper presents a parametric study on the impact of solar cells at the building 2 envelope on the generated power, energy consumption, comfort conditions (interior 3 temperature, relative humidity, discomfort hours, and lighting), and CO2 emissions 4 within a building. It considers the cell position on the facade (cell inside window, 5 two cells outside the window), orientation direction (north, east, south, west), and 6 location (wall, roof). The study is performed under the meteorological conditions in 7 the city of New Borg El Arab, Alexandria, Egypt. The numerical solution of the 8 physical model is solved using the Design-Builder software and is validated through 9 an experiment. The results reveal that solar cells on the facade and roof decrease the 10 annual energy consumption inside the facility by approximately 15% and 40%, 11 respectively, compared to a facility without cells. A cell installed on the roof facing 12 south has the highest annual generated power. For a solar cell on the wall, a cell 13 facing south produces the highest annual generated power and a cell facing north 14 produces the lowest. The temperature inside the facility is lower when the solar cells 15 are installed, and a cell facing south provides comfortable interior conditions in all 16 the investigated cases. A cell located inside the window produces the lowest light 17 intensity and a cell facing north produces the lowest CO2 emissions.