With the aim of addressing the significant contribution of buildings to global energy consumption and the growing need to establish a more harmonious connection between humans and nature in urban environments, the concept of green vertical systems has garnered considerable attention. These systems possess the potential to enhance the energy efficiency and environmental sustainability of buildings. This study seeks to explore the impact of living walls on the energy performance of buildings, specifically investigating the influence of a living-walled urban block on the ambient air temperature and its subsequent effect on building energy consumption. By comparing the cooling energy consumption of two typical buildings situated in Shiraz, southern Iran, with varying levels of greenery in different microclimates, we further ascertain the effectiveness of living walls in reducing energy consumption. To conduct this analysis, we employed coupled simulations utilizing EnergyPlus and Envi-met, which incorporated both the outdoor microclimate and the cooling energy consumption of the buildings. The urban block under consideration consisted of 48 three-story buildings (Case A) and five-story buildings (Case B) within a site measuring 120 m × 150 m. Our findings substantiate that the implementation of a living wall system can lower the ambient air temperature by a significant extent, with an average decrease of 1.35 °C and a maximum decrease of 2.25 °C. Consequently, living walls can effectively mitigate the urban heat island phenomenon by decreasing the temperatures of the surrounding buildings. Additionally, our investigations revealed a maximum energy saving of 15%, with microclimate exerting a 4.3% influence on these savings.