Adaptive Solar Control Through Rotating Louvers: A Material- Based Performance Study in Hot-Dry India

India’s building sector faces a rapidly increasing cooling demand, with façades playing a decisive role in regulating solar heat gain. Static shading devices often fail to address dynamic solar exposure, particularly in hot-dry climates where west and south-west orientations receive intense cumulative radiation. Rotating louver façades, as a form of adaptive envelope technology, offer the potential to reduce cooling loads while maintaining visual comfort. This study evaluates the thermal performance of rotating louvers constructed from aluminum, timber/wood-plastic composite (WPC), and fiber-reinforced polymer (FRP) in the hot-dry context of India. A representative classroom volume (7 × 8 × 3 m, WWR 40%) was modeled and simulated using parametric environmental analysis tools like Rhino/Grasshopper with Ladybug and Honeybee plugins and EnergyPlus. Louvers were tested at 0°, 45°, and 90° across west and south-west orientations. Results indicate that rotating louvers reduce annual solar irradiance by 75–80% relative to unshaded baselines. Among materials, FRP consistently achieved the lowest average irradiance and variability, demonstrating superior thermal stability, while Timber/WPC reduced peak irradiance effectively and aluminum maintained higher minimum values, potentially aiding daylight penetration. Orientation and angle analysis revealed that SW façades perform best with shallow mid rotations (0–45°), while W façades require mid steep angles (45–90°) to control afternoon peaks. The findings provide evidence-based guidance for material and angle selection in adaptive façades, offering practitioners actionable strategies to enhance energy efficiency and occupant comfort in hot-dry Indian climates.