## 1 Introduction  
The increasing awareness about the environmental impacts caused by energy production and consumption has focused attention on energy-intensive processes. The building industry is a critical sector for the economic and social development of cities because of the services provided but causes important environmental impacts since it is energy-intensive [1,2]. Buildings require large amounts of resources and energy, and significant emissions and wastes are generated. In Europe, the construction of buildings accounts for 36% and 40% of the CO2 emissions and energy consumption, respectively [3]. Buildings consume energy throughout their complete life, from construction to demolition. These environmental impacts include mining, materials manufacturing, construction, use, and demolition phases. During the operational phase, characterized by the specific provision of services, general heating and cooling demands, as well as the required maintenance, the energy demand of a building is both direct and indirect. The indirect consumption of energy can be attributable to the production of the materials used in this operational phase [4]. Nevertheless, specific requirements for a building's total energy and resource consumption over its lifetime must be implemented [5]. In this context, the Energy Performance Buildings Directive launched by the European Commission [6] aimed to provide a common strategy to implement actions for improving the energy efficiency of buildings and giving energy transparency by means of Energy Performance Certificates (EPCs) [7]. This directive introduced the concept of nearly Zero Energy Building (nZEB) target and requires all new buildings to be nZEB by the end of 2020 with most of the energy required coming from renewable sources [8]. The Spanish legislation is aligned with the European policies by means of the Royal Decree 235/2013 [9], which establishes the commitment to present an EPC to building users. This Royal Decree helps to inform about CO2 equivalent emissions caused by the use of energy, facilitating the implementation of measures to reduce these emissions and improve energy efficiency. However, although the EPC is mandatory in Spain, it is almost never calculated at the time of the pre-sale of a property, but only after the notarial deed. In fact, EPC is mandatory for new buildings or when selling or renting for the owners. But, a certain level of flexibility in reaching these goals is tolerated [10]. In this sense, the proposed methodology could define a new environmental performance metric useful for encouraging and promoting sustainability. Various green rating systems have been established globally to evaluate the sustainability of construction projects [11]. Specifically, LEED (Leadership in Energy and Environmental Design), BREEAM (Building Research Establishment Assessment Method), CASBEE (Comprehensive Assessment System for Building Environmental Efficiency), and Green Star NZ (New Zealand Green Building Council) are examples of green building rating systems. They have as commonality the environment as the key factor on which all of the rating systems focus (more than 75% of total sub-categories in any eating system). However, they can hardly be translated into tools for energy certification, and furthermore, they do not include a truly holistic approach during the use stage, which makes it difficult to know where the energy and environmental impact occurs and act on it. Specifically, in the context of university's institutions, the Global University Rankings (GURs), or the Universitas Indonesia (UI) GreenMetric aim to measure the performance of universities worldwide [12]. In both cases, the environmental variable has not been included to promote sustainability on campus and contribute to energy saving and mitigate climate change. Many works have evaluated the environmental impacts of buildings, their constituent materials, components, and systems to identify any opportunities to reduce their environmental impacts.