Thermal performance of green façades: Review and analysis of published data

Buildings consume about 30% of the world's resources and around 40% of the world's energy. The growing interest in energy saving and environmental sustainability in buildings, has led to green buildings and green façades being considered as innovative solutions. This paper analyses the thermal performance of green façades reported in the literature, and how that performance changes with type of façade (attached or detached), its orientation, the gap width between a detached façade and the external wall, climate conditions, and leaf area index. The results showed that during hot periods when the ambient air temperature was more than 30 °C, the gap temperatures for detached façades were more than 1 °C cooler than ambient air; and the temperatures of external walls with facades (detached or attached) were 3.2–3.5 °C cooler than external walls without façades. During cool and cold periods when the ambient air temperature was less than 20 °C, the temperatures of external walls with facades were about 3 °C warmer than without façades. The assessment confirms that green façades should be considered as appropriate options to reduce building energy consumption in both hot and cold climates. This performance assessment can support guidelines for urban designers, architects, and environmental engineers to adopt the principles of sustainable design and reduce energy consumption and greenhouse emissions. Finally, this work highlighted the lack of reported data on plant and substrate characteristics, all of which are considered important factors in thermal performance; these aspects require further investigation.