The integration of photovoltaic modules on buildings has always been an effective method to harness energy. In this day and time, the trend to make a building more energy efficient is very high, which makes building integrated photovoltaics (BIPV) a great option. If well designed not only does it produce clean energy but also adds a better aesthetic appearance to the building. BIPV is a great idea especially for old buildings that are being renovated as it adds to both the aesthetic appearance and a step towards sustainability.The thesis aimed to analyze the performance of a BIPV plant between monitored and simulated data for the year 2019 situated in Lugano, Switzerland. This BIPV plant was built in 2018 as a part of the renovation of the Palazzo Zurich building. The energy generated by this plant is mostly consumed by the building itself, hence this plant indicates the effort made towards the net-zero energy buildings (NZEB).To carry out this correlation, four basic steps were followed. Firstly, the BIM model was examined and studied thoroughly and a 3D model was developed in a format that can be imported into simulation software. Secondly, a weather data file was created for the exact location of the building as the building had a host of weather monitoring devices. In the creation of a weather data file, two methods were followed, in which, one worked in the favor of this thesis work, whereas, the other gave highly uncertain results. The main task in the weather data file creation was to calculate the beam and diffuse as the pyranometers on the building only recorded global horizontal and global vertical irradiation. The calculated beam and diffused were used in creating the weather data file which could be imported in simulation software to work further.Thirdly, the simulation software used to carry out this research was BIMsolar, specially made for BIPV applications. On simulating the BIPV system using BIMsolar the results were compared with the monitored output of the actual BIPV system in Lugano. The parameters such as PV module production and inverter AC production were compared along with an RMSE analysis of both.The results of this study were calculated in the form of root mean square error (RMSE) calculation. The RMSE value for the comparison between monitored and simulated data of PV module production and AC production data was found to be between 125 kWh to 135 kWh every month, whereas on an average daily basis this result was between 0.4 kW to 0.45 kW every hour. In conclusion, it can be inferred that the 3D model and the weather data file plays an important role in the performance of the simulated plant and can influence the result significantly.