A sustainable technology for improving the energy efficiency of buildings is the use of urban greening in order to reduce the energy consumption for air conditioning in summer and to increase the thermal insulation in winter. A worldwide growing interest in urban green is encouraging the application of the greening technology for more sustainable buildings. Building indoor air temperature depends on several different parameters related to the climate of the region, the building itself and its use. The main parameters influencing the microclimate are: external air temperature and relative humidity, incident solar radiation, long wave radiation exchange between the building surfaces and its surroundings, wind velocity and direction, air exchanges, physical and thermal properties of the building’s envelope mate- rials, design variables such as building dimensions and orientation, presence of artificial light, electrical equipment. green façades can allow the physical shading of the building and promote evapotranspiration in summer and increase the thermal insulation in winter. External wall surface temperature is a parameter useful to assess the effectiveness of green façades. an experimental test was carried out at the university of bari (italy) for three years. Three vertical walls, made with perforated bricks, were tested: two were covered with evergreen plants (Pandorea jasminoides variegated and Rhynco- spermum jasminoides) while the third wall was kept uncovered and used as control. Several climatic parameters concerning the walls and the ambient conditions were collected during the experimental test. The experimental data were used for developing a multiple regression equation regarding the dependence of the difference of external surface temperature between the green façades and the control wall and the weather conditions. The model shows a good predicting ability.
air-conditioning, energy savings, green walls, regression model, urban agriculture, urban heat island
 Norton, B.A., Coutts, A.M., Livesley, S.J., Harris, R.J., Hunter, A.M. & Williams, N.S.G., Planning for cooler cities: A framework to prioritise green infrastructure to mitigate high temperatures in urban landscapes. Landscape and Urban Planning, 134, pp. 127–138, 2015. https://doi.org/10.1016/j.landurbplan.2014.10.018
 Pérez, G., Coma, J., Martorell, I. & Cabeza, L.F., Vertical Greenery Systems (VGS ) for energy saving in buildings: A review. Renewable and Sustainable Energy Reviews, 39, pp. 139–165, 2014. https://doi.org/10.1016/j.rser.2014.07.055
 Tan, C.L., Wong N.H. & Jusuf, S.K., Effects of vertical greenery on mean radiant temperature in the tropical urban environment. Landscape and Urban Planning, 127, pp. 52–64, 2014. http://dx.doi.org/10.1016/j.landurbplan.2014.04.005
 Vox, G., Blanco, I., Campiotti, C.A., Giagnacovo G. & Schettini, E., Vertical green systems for buildings climate control. Proceedings of the 43rd International Symposium – Actual Tasks on Agricultural Engineering, Sveučilište u Zagrebu, Agronomski fakultet, Zavod za mehanizaciju poljoprivrede. Opatija, Croatia, 24-27/02/2015, pp. 723–732, 2015.
 Vox, G., Blanco, I., Fuina, S., Campiotti, C.A., Scarascia Mugnozza, G. & S chettini, E., Evaluation of wall surface temperatures in green facades. Proceedings of the Institution of Civil Engineers – Engineering Sustainability, 170(6), pp. 334–344, 2017. https://doi.org/10.1680/jensu.16.00019
 Berardi, U., Ghaffarianhoseini, A.H. & Ghaffarian Hoseini, A., State-of-the-art analysis of the environmental benefits of green roofs. Applied Energy, 115, pp. 411–428, 2014. http://dx.doi. org/10.1016/j.apenergy.2013.10.047
 Fernandez-Cañero, R., Emilsson, T., Fernandez-Barba, C. & Herrera Machuca, M.A., Green roof systems: a study of public attitudes and preferences in southern Spain. Journal of Environmental Management, 128, pp. 106–115, 2013. http://dx.doi.org/10.1016/j.jenvman.2013.04.052
 Santamouris, M., Cooling the cities – a review of reflective and green roof mitigation technologies to fight heat island and improve comfort in urban environments. Solar Energy, 103, pp. 682–703, 2012. http://dx.doi.org/10.1016/j.solener.2012.07.003
 Cheng, C.Y., Cheung, K.K.S. & Chu, L.M., Thermal performance of a vegetated cladding system on facade walls. Building and Environment, 45(8), pp. 1779–1787, 2010. https://doi.org/10.1016/j.buildenv.2010.02.005
 Jim, C.Y. & Tsang, S.W., Biophysical properties and thermal performance of an intensive green roof. Building and Environment, 46(6), pp. 1263–1274, 2011. https://doi.org/10.1016/j.buildenv.2010.12.013
 Köhler, M. & Poll, P.H., Long-term performance of selected old Berlin greenroofs in comparison to younger extensive greenroofs in Berlin. Ecological Engineering, 36(5), pp. 722–729, 2010. https://doi.org/10.1016/j.ecoleng.2009.12.019
 Perini, K., Ottelé, M., Fraaij, A.L.A., Haas E.M. & Raiteri, R., Vertical greening systems and the effect on air flow and temperature on the building envelope. Building and Environment, 46(11), pp. 2287–2294, 2011. https://doi.org/10.1016/j.buildenv.2011.05.009.
 Safikhani, T., Abdullah, A.M., Ossen, D.R. & Baharvand, M., A review of energy characteristic of vertical greenery systems. Renewable and Sustainable Energy Reviews, 40, pp. 450–462, 2014. https://doi.org/10.1016/j.rser.2014.07.166
 Gago, E.J., Roldan, J., Pacheco-Torres R. & Ordóñez, J., The city and urban heat islands: A review of strategies to mitigate adverse effects. Renewable and Sustainable Energy Reviews, 25, pp. 749–758, 2013. https://doi.org/10.1016/j.rser.2013.05.057
 Cameron, R.W.F., Taylor J.E. & Emmett, M.R., What’s ‘cool’ in the world of green façades? How plant choice influences the cooling properties of green walls. Building and Environment, 73, pp. 198–207, 2014. https://doi.org/10.1016/j.buildenv.2013.12.005
 Yang, F., Yuan, F., Qian, F., Zhuang, Z. & Yao J., Summertime thermal and energy performance of a double-skin green facade: A case study in Shanghai. Sustainable Cities and Society, 39, pp. 43–51, 2018. https://doi.org/10.1016/j.scs.2018.01.049
 Raji, B., Tenpierik, M.J. & van den Dobbelsteen, A., The impact of greening systems on building energy performance: A literature review. Renewable and Sustainable Energy Reviews, 45, pp. 610–623, 2015. https://doi.org/10.1016/j.rser.2015.02.011
 Medl, A., Stangl, R. & Florineth, F., Vertical greening systems – A review on recent technologies and research advancement. Building and Environment, 125, pp 227–239, 2017. ISSN 0360-1323. https://doi.org/10.1016/j.buildenv.2017.08.054
 Pérez-Urrestarazu, L., Fernández-Cañero, R., Franco-Salas A. & Egea, G., Vertical Greening Systems and Sustainable Cities. Journal of Urban Technology, 22(4), pp. 65–85, 2016. https://doi.org/10.1080/10630732.2015.1073900
 Lin, H., Xiao, Y. & Musso, F., Shading Effect and Heat Reflection Performance of Green Façade in Hot Humid Climate Area: Measurements of a Residential Project in Guangzhou, China. IOP Conference Series: Earth and Environmental Science, 146, p. 012006, 2018. https://doi.org/10.1088/1755-1315/146/1/012006
 Kontoleon, K.J. & Eumorfopoulou, E.A., The effect of the orientation and proportion of a plant-covered wall layer on the thermal performance of a building zone. Building and Environment, 45, Suppl. 5, pp. 1287–1303, 2010. http://dx.doi.org/10.1016/j.buildenv.2009.11.013
 Giordano, R., Montacchini, E., Tedesco S. & Perone, A., Living Wall Systems: A T echnical Standard Proposal. Energy Procedia, 111, pp. 298–307, 2017. http://dx.doi.org/10.1016/j.egypro.2017.03.093
 Eumorfopoulou, E.A., & Kontoleon, K.J., Experimental approach to the contribution of plant-covered walls to the thermal behaviour of building envelopes. Building and Environment, 44(5), pp. 1024–1038, 2009. https://doi.org/10.1016/j.buildenv.2008.07.004
 Campiotti, C.A., Schettini, E., Alonzo, G., Viola, C., Bibbiani, C., Scarascia Mugnozza, G., Blanco, I. & Vox, G., Building green covering for a sustainable use of energy. Journal of Agricultural Engineering, 44(2s), pp. 253–256, 2013. https://doi.org/10.4081/jae.2013.292
 Blanco, I., Schettini, E., Scarascia Mugnozza, G., Campiotti, C.A., Giagnacovo, G. & Vox, G., Vegetation as a passive system for enhancing building climate control. Acta Horticulturae, 1170, pp. 555–562, 2017. https://doi.org/10.17660/actahortic.2017.1170.69
 Vox, G., Blanco, I. & Schettini, E., Green façades to control wall surface temperature in buildings. Building and Environment, 129, pp. 154–166, 2018. https://doi.org/10.1016/j.buildenv.2017.12.002
 Hunter, A.M., Williams, N.S.G., Rayner, J.P., Aye, L., Hes, D. & Livesley, S.J., Quantifying the thermal performance of green façades: a critical review. Ecological Engineering, 63, pp. 102–113, 2014. http://dx.doi.org/10.1016/j.ecoleng.2013.12.021
 UNI EN 1745 2012. Masonry and masonry products - Methods for determining thermal properties. UNI – Ente Nazionale Italiano di Unificazione – Italian Organization for Standardization; IT.
 Fumo, N. & Rafe Biswas, M.A., Regression analysis for prediction of residential energy consumption. Renewable and Sustainable Energy Reviews, 47, pp. 332–343, 2015. DOI: 10.1016/j.rser.2015.03.035 https://doi.org/10.1016/j.rser.2015.03.035
 Yildiz, B., Bilbao J.I. & Sproul, A.B., A review and analysis of regression and machine learning models on commercial building electricity load forecasting. Renewable and Sustainable Energy Reviews, 73, pp. 1104–1122, 2017. https://doi.org/10.1016/j.rser.2017.02.023