# Enhancing Knowledge on Energy Refurbishment of Buildings and Green Procurement through Living Labs
## 1 Introduction  
The growing severity of global warming and climate change highlights the importance of EU buildings in meeting the energy, emissions, and environmental standards outlined in the European Green Deal. By 2030, new buildings are required to be carbon-neutral, with the goal for all buildings to achieve this standard by 2050 [1]. Buildings in the EU account for the lion's share of Europe's energy consumption, consuming 40% of energy and producing 36% of greenhouse gas emissions. This significant impact is largely due to the prevalence of energy-inefficient buildings that rely heavily on fossil fuels [2]. A study conducted by the Buildings Performance Institute Europe (BPIE), encompassing data from 16 EU countries, reveals that a staggering 97% of the building stock requires energy refurbishment to realize the vision set for 2050. Moreover, addressing this concern is a strategic response to increasing energy prices: the EU's least efficient buildings consume vastly more energy than newly constructed or adequately renovated ones [3]. Considering that the building stock in the EU accounts for more than one third of its total greenhouse gas (GHG) emissions, and with projections showing that 85% of these buildings will remain in use until 2050, there is an urgency to implement effective measures to reduce their environmental impact [2]. One of the most effective measures to achieve a significant reduction in greenhouse gas emissions from EU buildings is to prioritize energy efficiency improvements [4]. This can be accomplished by implementing policies and measures that focus on retrofitting and renovating existing buildings. By improving insulation, upgrading heating and cooling systems, and integrating renewable energy technologies, buildings can become more energy efficient and reduce their carbon footprint [5]. In addition to energy efficiency improvements, it is crucial to invest in sustainable building materials and constructionpractices. This includes using materials with lower embodied carbon, such as recycled or locally sourced materials, and implementing sustainable construction techniques that minimize waste and emissions during the building process [6]. Furthermore, promoting the use of smart technologies and digitalization can also contribute to reducing energy consumption and optimizing building performance [7]. These policies can include setting mandatory energy performance standards for buildings, providing financial incentives and subsidies for energy-efficient renovations, and promoting the use of renewable energy sources through feed-in tariffs or tax credits [8; 9]. Additionally, the concept of green public procurement (GPP) plays a vital role in promoting sustainable practices in EU building stock. GPP involves the consideration of environmental criteria, such as energy efficiency and the use of sustainable materials, in the procurement of goods and services by public authorities [10]. By incorporating GPP into the procurement process, a significant impact on reducing greenhouse gas emissions and promoting sustainable practices in the construction industry can be achieved [11; 12]. To effectively implement GPP, it is essential to establish clear guidelines and criteria for public authorities to follow when procuring goods and services for building projects. These guidelines should prioritize energy-efficient products and materials that have a lower environmental impact throughout their life cycle [13]. Furthermore, monitoring and evaluation mechanisms should be put in place to ensure that GPP criteria are being effectively implemented and to track the environmental performance of purchased goods and services [14]. To support the implementation of green public procurement in the EU, several policies and measures have been established. Italy, for example, has implemented a range of policies to promote green public procurement.