Enhancing Outdoor Environmental Comfort: A Review of Façade-Surface Strategies and Microclimate Impacts

Building façades traditionally focus on enhancing indoor environmental quality and improving energy performance, but undermine their influence on Outdoor Environmental Comfort (OEC), including thermal, acoustic, and visual conditions. With technological advancements in envelope design, research on new materials and green systems has been introduced in the last few decades. This review examines the role of two key elements—façade materials and green façades—in shaping OEC. A total of 41 peer-reviewed studies (24 on urban scale and 17 on building scale) were categorized into three focus areas: (1) outdoor thermal comfort; (2) outdoor acoustic comfort; and (3) outdoor visual comfort. The analysis was structured across three levels: (a) Performance Determinants; (b) Metrics/Models; and (c) Material or Façade Types. We proposed this analytical structure to highlight the interactions between building façades and OEC domains (thermal, acoustic, and visual comfort). Our results showed façade treatment can impact all three comfort factors related to OEC, but trade-offs must be evaluated. Moreover, the findings highlighted that additional research is required to cover variations in both climate and context conditions, due to their close association with the OEC. Finally, the conceptual framework is presented to synthesize the three comfort domains for sustainable outdoor environments.