Greenery on buildings is being consolidated as an interesting way to improve the quality of life in urban environments. Among the benefits that are associated with greenery systems for buildings, such as energy savings, biodiversity support, and storm-water control, there is also noise attenuation. Despite the fact that green walls are one of the most promising building greenery systems, few studies of their sound insulation potential have been conducted. In addition, there are different types of green walls; therefore, available data for this purpose are not only sparse but also scattered. To gather knowledge about the contribution of vertical greenery systems to noise reduction, especially a modular-based green wall, two different standardised laboratory tests were conducted. The main results were a weighted sound reduction index (Rw) of 15dB and a weighted sound absorption coefficient (α) of 0.40. It could be concluded that green walls have significant potential as a sound insulation tool for buildings but that some design adjustments should be performed, such as improving the efficiency of sealing the joints between the modular pieces

Green roofs are artificial ecosystems that provide a nature-based solution to environmental problems such as climate change and the urban heat island effect by absorbing solar radiation and helping to alleviate urban environmental, economic, and social problems. Green roofs offer many benefits in terms of heat and water conservation as well as in terms of energy costs. This work proposes the design of an extensive and environmentally sustainable green roof for the Faculty of Engineering building in Bilbao. The green roof will be made from the composting of food waste generated in the building’s own canteen. Therefore, the main objective of this study is to calculate the solar efficiency of a sustainable green roof, evaluate its thermal performance, and quantify the impact that its implementation would have on energy consumption and the thermal comfort of its users. The results obtained confirm that an environmentally sustainable green roof has a positive effect on summer energy consumption and that this effect is much greater when there is water on the roof, as shown by the difference in energy savings between the dry (−53.7%) and wet (−84.2%) scenarios. The data show that in winter the differences between a green roof and a non-vegetated roof are not significant. In this case, the estimated energy consumption penalty (0.015 kWh/m²) would be 10% of the summer gain.