Designing the Building Skin for Daylight in Cold-Climate Classrooms: An Orientation-Specific Comparison of Façade and Roof Glazing Strategies

Daylighting strategies for cold-climate classrooms must provide sufficient and well-distributed daylight while limiting unnecessary envelope transparency. This study compares orientation-specific façade and roof glazing configurations in a parametric 75 m² classroom under Quebec climatic conditions. Four façade configurations varying window area, sill and head height, and upper-level glazing distribution, together with five skylight arrangements at two roof-glazing levels, were evaluated across eight orientations using ClimateStudio. Performance was assessed through spatial Daylight Autonomy (sDA), Annual Sunlight Exposure (ASE), Useful Daylight Illuminance within the autonomous range (UDIa), mean and minimum illuminance, and daylight uniformity. Results show that orientation and glazing geometry strongly condition the benefit of additional transparent area. Southern and western orientations achieve daylight sufficiency with the baseline façade configuration, while larger windows provide limited additional benefit and can reduce uniformity. Northern orientations benefit more clearly from increased façade glazing and top lighting. Skylights are particularly effective at improving minimum illuminance and rear-zone distribution when positioned near the back of the room, while high-level façade glazing can improve daylight penetration without proportionally increasing total glazed area. The findings support an orientation-specific decision framework for early-stage building-skin design that prioritizes the placement and distribution of glazing rather than glazing ratio alone.