The study aims to address the knowledge gap in the school building-integrated PV (SBIPV) across diverse climate zones in Iran, focusing on developing energy efficiency, daylight performance, and visual comfort. Utilizing simulation models and sensitivity analysis, it compares 34 PV panels integrated as rooftop (PV-R) and overhang shading (PV-O) to define optimal configurations for each climate. Metrics include PV energy generation (PVEG), Energy Use Intensity (EUI), Spatial Daylight Autonomy (sDA), and Spatial Glare Autonomy (sGA). Results show that PV-Rs outperform PV-Os in energy savings, achieving up to 55.6% savings in arid climates like Isfahan, though 45.74% supplemental energy remains necessary in the humid climates of Bushehr. The maximum energy savings in Tehran and Yazd are 40.60% and 24.70%, respectively, while, similar to Bushehr, no energy saving is recorded in the Mediterranean climate of Sari. PV-O systems, however, demonstrate superior glare reduction, enhancing visual comfort significantly, especially in Mediterranean climates. Daylight performance meets established standards in most regions, although sDA decreases with PV-O integration. Sensitivity analysis highlights PV dimensions and power output as key factors in optimizing energy and visual outcomes. For the first time, building energy performance simulation of the latest version of Ladybug Tools (v.1.8.0) is validated by ANSI/ASHRAE Standard 140-2023.