This article presents the results obtained an experiment carried out to measure the thermal impacts of green walls on buildings. The experiment deals with full monitoring of a green wall set up on a scaled down experimental mockup of buildings located in La Rochelle city. Results underline the positive effect of green walls in summer and show moderate reduction of heat losses in winter. The distinction made between measured heat gains and heat losses through the compared facades helps to apprehend the energy impact of the envelopes greening. Besides, we analyzed through experimental observations the dynamic behavior of the green wall system, and we highlighted the importance of such an experimental model to take into account the vertical hygrothermal effects. The primary objective is better understanding of the thermohydric behavior and the energy impact of green walls by direct comparison between data recorded simultaneously on different configurations of buildings and streets with and without use green walls. Measurements of temperature, humidity and heat fluxes through facades with and without greening provide valuable data to assess performances of this technique, to analyze the thermal effects, and finally this gives data for further numerical studies. (C) 2017 Elsevier B.V. All rights reserved.