Dynamic energy and FEM-based acoustic analysis of fixed flat horizontal window overhangs

Solar shading devices, such as façade overhangs, offer dual benefits in reducing building energy demand and modulating acoustic transmission, yet their performance is contingent on design specificity and climatic context. This study evaluates the integrated thermal and acoustic effects of fixed horizontal overhangs through dynamic energy simulations and finite element modeling (FEM) in tropical (Indonesia) and temperate/continental climates (China). Results demonstrate that increasing overhang depth reduces annual energy consumption by up to 13.27% (14.23% HVAC-specific reduction at 140 cm depth), with diminishing returns beyond 80–100 cm projections. Daylighting remains above 300 lux, adhering to EN 12464-1 standards. Acoustically, overhangs attenuate low-frequency noise (up to + 12 dB IL at 100 Hz) but amplify mid-frequency transmission (e.g., − 3 dB IL at 315 Hz) due to diffraction effects. A balanced approach is necessary to ensure energy savings, adequate daylight, and effective noise control.