## 5 Results and Discussion  
The overall assessment of the thermohygrometric benefits on the simulated model was made by comparing the results obtained for the VGS models and the reference concrete model, analyzing external surface temperatures and operative temperatures, both in summer and winter. All the graphs refer to the south-facing walls, and the physical parameters used are consistent with the species suitable for the different systems, as indicated above and in [67]. The trends of outside face temperature for each category and for the concrete model, compared with outside air temperature, are shown in Figures 4 and 5, in summer and winter conditions, respectively. The summer chart shows the data obtained during the simulation performed in the last week of July (25-31/07), the hottest day of the summer according to the meteorological data analysis [66]. The GBS reduce concrete surface outside face temperatures by about 1.5 \({}^{\circ}\)C, due to the shading effect of trees and climbing species. There are no significant differences in the trends of the GTB and GCB models as both act only through shading and do not influence the temperature of the wall with the transpiration process. [PERSON] [23] and [PERSON] et al. [32] instead reported up to a 25% reduction in the outside surface temperatures for the GBS. The Different results could be due to the different height and position of the trees or climbing species or to a greater window area of the analyzed model. The GCC reduce the temperature of the concrete model on average by about 5 \({}^{\circ}\)C, confirmed by the empirical results obtained by [68], and the GMC by about 6 \({}^{\circ}\)C, due to the presence of soil, which also adds the evaporation process. The GW systems remarkably reduce the surface temperatures, also lower than the ones of outside air. The most performing systems are the LS and HS that reduce the maximum temperature of the concrete model up to 13 \({}^{\circ}\)C, included in the range of values obtained by [PERSON] et al. [69]. These systems record higher evaporation values from the soil, having thick and continuous layers. Figure 4: Summer (25-31/07). Comparison between the external surface temperatures of the south wall for each category, the concrete model and outside air. The winter chart shows the data obtained during the simulation performed in the first week of December (01-07/12), the coldest day of the year. The trend of the external surface temperature of the GBS coincides with that of the bare wall, as in this season they only act as wind barriers; the latter effect could be more relevant with denser vegetation. The GCS increase the surface temperature by about 1 \({}^{\circ}\)C on average, during the day, similarly to the results obtained by [70], as they have a better behavior as wind barriers. The GW, instead, follow the trend of the outside air temperature, with negligible variations, increasing the external surface temperature up to 8 \({}^{\circ}\)C higher than the reference. No simulations were found in the winter period comparable with those carried out. The influence of the different models on the summer and winter operative temperature is shown in Figures 6 and 7, respectively. In summer (Table 5), the HS have the most significant impact in lowering the operative temperature: up to 9 \({}^{\circ}\)C less than the concrete model. These results derive from the higher thermal mass of the soil and from a higher LAI value than the other systems; in fact, the HS, thanks to the high thickness of the substrate, can host larger species and therefore greater foliar density. The LS, MV and GMC have similar trends, with a reduction in peak temperatures of between 4 and 8 \({}^{\circ}\)C, similarly to the field measurement on a living wall made by [71]. In these cases, the thermal mass of the soil, being less thick, has less effect on lowering temperatures. The GCC lower the temperatures between 3 and 6 \({}^{\circ}\)C, decreasing temperatures thanks to the transpiration of the foliage and shading.