Exploring the impact of emissivity and orientation of fully glazed facades on urban microclimates

Fully glazed façades are increasingly common in modern architecture, yet their influence on outdoor conditions remains underexplored. This study examines how glass emissivity (0.84, 0.5, 0.3, 0.07) and façade orientation (0°, 45°, 90°, 135°, 180°, 225°, 270°, 315°) affect mean radiant temperature and longwave radiation at a site in Adelaide, South Australia. Using ENVI-met (V5.6.1), 64 simulations were run for the city’s hottest and coldest days. Results show that higher-emissivity façades increase MRT and LW Rad, particularly in summer. MRT emerged as the most sensitive parameter to emissivity changes, with seasonal variation affecting comfort. In winter, higher emissivity slightly improves conditions, while in summer, lower emissivity enhances outdoor environment. Façade orientations of 0°, 225°, 270°, and 315° were linked to the highest MRT and LW Rad values. These findings underscore the importance of façade materials and orientation in shaping outdoor microclimates and offer valuable insights into climate-sensitive urban design. • The emissivity of glazing and glazed facades significantly influences the outdoor microclimate. • Glazing emissivity of 0.84 increases MRT by 5 °C and longwave radiation by 105 W/m 2 , compared with a glazing emissivity of 0.07, on the hottest summer day at a vertical surface 1.40 m above ground level. • Glazing emissivity of 0.07 improves outdoor microclimates in summer but marginally worsens outdoor microclimates in winter.