Vertical Green Structures (VGS) emerged as a building skin Nature-based Solution (NbS) aside from green roofs. The motivation underlying this VGS exploitation is fast urbanisation and the need to limit both land consumption and vegetation loss. These structures can provide several ecosystem services like air purification, biodiversity enhancement, and noise reduction. Although the usage of VGS offers different versatile and multi-scalar benefits in the built environment, they still need to respond to all the requirements of social, economic, and environmental sustainability. Over the last decades, technologies of VGS have been developed and new product types have become available in the market. This paper presents the overall development and benefits of VGS, and aims to provide a taxonomy by considering a systematic and interdisciplinary approach. The current market overview analyses and compares different aspects (i.e., environmental and economic features) of the products for a better understanding of the current state-of-the-art—from single component to system scale. The findings of this review lead to some suggestions to enhance the level of sustainability and increase the potential benefits. They look at both research and practice requirements to orient the users in selecting the most optimal VGS solution available in the market.

Portugal, Italy, and Norway differ by energy performance of buildings and gross domestic product (GDP). Portugal has significantly highest thermal discomfort with harsher winters. In 2021, 80% of Portuguese buildings had a low energy rating, with 75% of buildings without thermal insulation, highly contributing to the energy poverty (EP) of the country. In Italy, despite a generally mild climate, the building stock has low thermal performance. The most affected areas are the suburban and peri-urban ones, with an EP rate in southern regions between 13% and 20% compared to 8.8% at national level. Moreover, 65% of buildings were constructed before the first law on energy saving criteria and a 25% of it has never undergone any work of maintenance or improvement. Norway, despite the limited studies performs well respect to other European Economic Area and European Union countries, in investing and using indicators to enhance and monitor the green energies’ use. Because of energy price growth, seasonal price fluctuations, and different energy tariffs, energy inequality is increasing. EP risk is underestimated, masked by Norway’s high GDP and regional price disparity. Energy inequality is increasing due to energy price growth, seasonal price fluctuations, and energy prices’ geographical inequality. The barriers in reducing EP are the underestimation of risk masked by the high GDP, and the need of homogenized prices in Norway. This study provides an overview to discuss EP awareness and it assesses the drivers and barriers that influence building’s energy efficiency renovation.

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