Investigating the Impact of Vertical Green Facades on Energy Efficiency and Carbon Footprint in Office Buildings: A Study of Climatic Regions in Iran

Document Type : Original Article

Authors

1 Department of Architecture, Rasht Branch, Islamic Azad University, Rasht, Iran.

2 Department of Architecture, Ra.C., Islamic Azad University, Rasht, Iran.

3 Department of Horticulture, Ra.C., Islamic Azad University, Rasht, Iran.

Abstract

Global warming and climate change are among the most pressing environmental challenges of the 21st century. With annual emissions of 996,753 megatons of carbon equivalent, Iran holds a significant share in global greenhouse gas emissions. The building sector, responsible for about 40% of national energy consumption, plays a major role in this context. This study evaluates the impact of vertical green façades on energy consumption and carbon emissions in office buildings across five distinct climate zones in Iran. Three façade types—conventional (non-vegetated), direct green, and indirect green—were modeled using DesignBuilder and SimaPro software. The simulation results were analyzed using ANOVA and Tukey’s post hoc tests in Python.



Results show that the effectiveness of green façades is strongly climate-dependent. In the hot-humid climate, the direct green façade achieved the highest reduction in energy use (5.17%) and carbon emissions (6%). In the cold climate, the indirect green façade reduced energy consumption by 7.29%. In the semi-arid zone, only the direct green façade showed positive performance, reducing energy use by 1.69%. However, in the temperate-humid climate, both types of green façades increased energy consumption (2.28–2.43%) and carbon emissions (11.26–12.21%). Significant differences were found among façade types in all climates (P<0.05), with large effect sizes (η² = 0.49–0.81). Two-way ANOVA confirmed a significant interaction between climate and façade type for both energy use (P = 0.0032) and carbon emissions (P = 0.0028).



These findings support the development of climate-specific green façade strategies and offer valuable insights for sustainable design and climate change mitigation efforts.

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