Energy: ENEA provides guidance for PAs on green roofs and walls

Encouraging the adoption of green roofs and walls in buildings throughout the country as an essential step of the strategies to improve the efficiency of the Italian building stock is the objective of the guidelines drawn up by the Department of Energy Efficiency Unit as part of “Italia in Classe A^[1]”, addressed to the Public Administration and local authorities to provide an overall picture on what is more and more considered an actual building component. The EU Commission also recognizes that efficient buildings, with low energy consumption and integrating ecological elements like hanging gardens and green walls with innovative construction materials, can bring environmental, social and health benefits to urban areas.

The publication was presented during a webinar on Thursday, July 4 in Rome. An entire chapter reports and analyses scientific findings in support of the advantages provided by the installation of green roofs and walls in improving the energy performance of buildings and obtaining economic and social benefits on both building and urban scale. The "green cover" on roofs and walls, in fact, can reduce internal temperatures in summer by up to 3 °C and allows to reduce the heat flow by almost 50%, by providing shade and removing heat from the air through the process of evapotranspiration which occurs in plants.

The main types of green roofs and walls on the market, their planning, design and maintenance are also dealt with extensively. Two chapters are dedicated to good practices implemented by local administrations and the projects already completed and the policies for their promotion are presented. The presence of plants near a building also affects the energy interactions between the building and the outdoor environment, improving summer comfort for outdoor spaces and fulfilling the function of thermal insulation, limiting thermal oscillations. Green roofs and walls can also mitigate summer temperature peaks thanks to the evapotranspiration of plants and their shading efefct against direct solar radiation on buildings and surrounding surfaces, allowing to mitigate the heat island effect in urban centers.

 “The guidelines provide concrete and regulatory guidance on how to best implement sustainability in construction, helping local governments and other public bodies understand the benefits and techniques of implementing green roofs and walls, promoting their diffusion and integration in urban areas,” explained Patrizia De Rossi, researcher at the Energy Efficiency Unit Department. “The use of green façades is an innovative solution that reduces the heating and cooling energy demand of buildings,” concluded De Rossi.

Finally, the publication explains the research method underlying an initial survey conducted by ENEA on the current implementation status of green roofs and walls at a national level, with the presentation of a questionnaire for data collection addressed to trade associations, public administrations and operators, presently on the website of the Department of Energy Efficiency Unit.