## 1 Introduction  
The fourth report of the Intergovernmental Panel for Climate Change (IPCC, 2007) [1] highlighted the main responsibility of human action in the emission of greenhouse gases responsible for climate change: \"The global increase in the concentration of carbon dioxide is mainly due to the use of fossil fuels and changes in land use, while increases in methane and nitrous oxide are mainly due to agriculture.\" In September 2008, the authoritative international programme Global Carbon Project published the results of the Carbon Budget 2007 [2], according to which the annual increase in CO\({}_{2}\) in the chemical composition of the atmosphere for 2007 was equal to 2.2 ppmv (parts per million volume) compared to 1.8 ppmv in 2006, while in the last twenty years it was equal to 1.5 ppmv. This increase brought the concentration of carbon dioxide in the atmosphere to 383 ppmv in 2007; i.e., 37% above that existing at the beginning of the Industrial Revolution (equal to about 280 ppmv). The latest data on atmospheric CO\({}_{2}\) concentration measurements, published on the US National Oceanic and Atmospheric Administration (NOAA) website, show that the average global concentration of carbon dioxide is constantly increasing: 410.24 ppm in April 2018, 413.32 ppm in April 2019 [3]. The scientific community has documented that the current concentration is the highest in 800,000 years [4]. The European Commission [5] is directing operators in the sector towards a wide range of technological solutions that can be used to drastically reduce the energy consumed by real estate assets. The energy consumption of a building is influenced by several factors, such as the geometry and orientation of the building [6; 7], the performance of the building envelope [7; 8] and the efficiency of building systems, as well as usage patterns, energy management and user behaviour. Italian legislation has implemented the strategic environmental objectives defined by the European Commission [9] (in agreement with the National Action Plan on Green Public Procurement--NAP GPP [10]) through the issuing of the New Italian Code of Public Procurement (Legislative Decree 50/2016) [11; 12], adopting the \"Minimum environmental criteria for the award of design services and new construction, renovation and maintenance of public buildings\" (Ministry of the Environment, Decree 11 October 2017) [13; 14]. In the literature there are various approaches for assessing the sustainability of construction/ restructuring interventions, with reference to the Italian national context. The study by [PERSON] et al. [15] shows that, in Italy, there are many attempts to apply technical-economic evaluations on energy saving strategies. In this regard, there are experiments relating to optimal conditions of comfort in relation to costs for school buildings [16]. Similar approaches have been applied to residential buildings [17]. However, fewer studies consider life cycle cost analysis (LCC) based assessment approaches. LCC is a management accounting tool for the economic assessment of choices made at the planning stage [18], and these choices can affect up to 80% of post-construction life cycle costs [19]. In particular, the study by [PERSON] et al. [15] shows that the life-cycle costs of a demolition and reconstruction operation are higher than those of a renovation operation. And, in the case of demolition and rebuilding, the costs of selective demolition are higher than those of mechanical demolition. The study by [PERSON] et al. [16] discusses a methodological approach to the design of energy remediation measures based on an in-depth energy audit with in situ measurements allowing the complete characterisation of the building's HVAC system and internal conditions. Subsequently, the cost-optimal approach is applied to compare different retrofit scenarios, considering both the interventions on the building envelope and on the plant systems.