Adaptive façade application in an office building to enhance daylight and visual comfort under various climatic conditions

Adaptive façades are increasingly used to reconcile high daylight availability with visual comfort, yet their cross-climate performance in U.S. office buildings remains underexplored. This study evaluates a triangular-module external shading device for a generic south-facing open-plan office in three representative U.S. climates: Boston (5A, cool-humid), Houston (2A, hot-humid), and Phoenix (2B, hot-dry). A parametric Rhino/Grasshopper model was simulated in ClimateStudio using climate-based daylighting and glare metrics, including spatial Daylight Autonomy (sDA300/50%), Annual Sunlight Exposure (ASE1000/250), Daylight Factor (DF), point-in-time illuminance, and Daylight Glare Probability (DGP), for the unshaded base case and six louvre rotation angles from 15° to 90° (the fully closed 0° state admits no daylight and was not simulated). The unshaded base case achieved full daylight autonomy sDA300/50% = 100% in all climates but exhibited high ASE (up to 65%) and frequent disturbing or intolerable glare at a central workstation. Rotating the louvres progressively reduced ASE and glare while preserving useful daylight. An intermediate 45° configuration emerged as the most balanced mode, maintaining high daylight autonomy sDA300/50% ≥ 93% across all climates, while roughly halving ASE (1000/250) relative to the base case and shifting DGP categories predominantly into the imperceptible to perceptible range. More closed positions (≤ 30°) nearly eliminated ASE and glare but reduced daylight autonomy below 50%, effectively removing the office from the “daylit” category. This ordering of configurations was consistent across all three climates. Overall, the results indicate that simple geometric modulation of an adaptive façade can manage daylight and visual comfort across climatically distinct U.S. conditions, and that an intermediate angular range around 45° offers the best-balanced operation among the tested configurations, providing practical guidance for façade design and control in office buildings.