The solar spectrum influences the power generation of photovoltaic (PV) cells, which subsequently affects the performance of semi-transparent PV windows. This paper presents a thermal and electrical decoupling model and a power generation model for semi-transparent PV windows, both of which incorporate the solar spectrum based on external quantum efficiency. The models for the temperature and power generation of the PV window under real-time spectra were analyzed, and their accuracy was validated through outdoor experiments. The heat transfer model demonstrates a root-mean-square error of 0.97 ℃ and an average absolute error of 0.89 ℃, with a correct rate of 96.3%. Regarding the power generation model, the root-mean-square error is 2.63 W and the average absolute error is 2.42 W, with a correct rate of 85%. This study offers a more precise model for evaluating the thermal and electrical performance of semi-transparent PV windows, which is important for promoting the integration of PV technology in building envelopes.