Climate change mitigation measures include the addition of vegetation to existing buildings to reduce heat stress in hot summers. In this study, the influence of green façades on the indoor climate is modeled by coupling two different numerical simulation tools: The microclimate simulation tool ENVImet is utilized to model the vegetation and surroundings in the first step. Subsequently, the building energy simulation EnergyPlus in Honeybee/Grasshopper is used to model the indoor climate. Using weather data as a link between the tools, different scenarios (traditional self-climbing plants, plant boxes, and green walls) of green façade designs for a residential building are modeled as a case study. Results show a reduction of operative temperature of up to 3.93% for the most efficient design scenario, the green wall, which corresponds to a 20.09% improvement of the predicted mean vote.