The Impact of Secondary Skin on Energy Use Intensity and Daylight Factor on the Facade of an Educational Building

This study evaluates the impact of secondary skin design on the Energy Use Intensity (EUI) and Daylight Factor (DF) of the Psychology Building at Diponegoro University, Semarang. The research employs energy simulation and daylight analysis using Autodesk Revit, with performance benchmarks based on the Green Building Council Indonesia (GBCI) and the Indonesian National Standard (SNI 03-2396-2001). Results show that the existing secondary skin achieves an EUI of 229 kWh/m²/year and a DF of 1.9%. Without the secondary skin, the EUI increases to 236 kWh/m²/year and DF rises to 3.9%. Two alternative designs were proposed: a horizontal louver system, which achieved an EUI of 228 kWh/m²/year and DF of 3.0%, and an egg-crate design, which achieved an EUI of 229 kWh/m²/year and DF of 3.5%. The horizontal louver provided the best balance between energy savings and daylight quality. Beyond building performance, this research highlights the role of façade strategies in reducing operational energy demand, lowering carbon emissions, and supporting Indonesia's energy transition agenda. By optimizing daylight and energy use, secondary skin design contributes to environmental sustainability and aligns with global goals such as SDG 7 (Affordable and Clean Energy), SDG 11 (Sustainable Cities and Communities), and SDG 13 (Climate Action).