Development of a decision-support tool for assessing the energy performance of living walls using a novel approach

Problems caused by climate change and their relation to building energy use have necessitated architectural precautions. One such measure is the integration of vegetation into buildings. Vegetation can be incorporated into roofs or façades; in façades, living wall systems—with plant and growing medium layers integral to façade —offer an alternative to conventional green façades. Despite its energy saving potential, there is currently a notable absence of a dedicated simulation tool to evaluate the energy performance of buildings with exterior living walls. Moreover, users deprived of accessible tools to evaluate how various building- and living wall–related variables affect overall energy performance. Therefore, a study aiming to develop a model that enables rapid assessment of living walls’ impact on building energy efficiency was conducted, addressing this gap by analyzing interactions between living walls and buildings across multiple parameters such as exterior wall, building, and plan characteristics, climate, and orientation. This paper presents its output; a decision-support model and tool, underpinned by a comprehensive database, to evaluate the impact of key parameters—including climate zone, orientation, story height, U-value, and plant traits such as albedo, Leaf Area Index (LAI), and leaf transmittance—on building energy performance as innovative approach. In developing the model and database, building energy performance was examined via EnergyPlus simulations, coupled one-way with Envi-Met concerning the microclimate conditions of the building zones with a living wall. The tool supports annual and summer-period assessments, accounting for building usage duration as a key factor in assessing the energy performance and impacts of living walls.