## 1 Introduction
Life cycle assessment (LCA), life cycle energy assessment (LCEA), and life cycle carbon emissions assessment (LCCO2A) assess the environmental impacts and resources and energy consumption associated with the building industry [13]. Some factors contribute to discrepancies in results between different types of life cycle studies. Among then, the types of resource input and environmental loadings considered and the types of energy in focus (primary vs. secondary) are issues that must be taken into account to establish a common, simplified, and comprehensive tool that enables the decision-making process. LCA considers the entire life cycle of a building in terms of energy and materials used and, consequently,a high number of LCA studies have been carried out to evaluate the environmental impacts due to the construction sector. [PERSON] et al. [14] assessed the use of energy and environmental impact in the production of five construction materials: wood, aluminum, glass, concrete, and ceramics. [PERSON] et al. [15] analyzed the environmental impact of different types of concrete and steel used in the construction industry in China. [PERSON] et al. [16] developed a review of LCA applied within the building sector from 2000 to 2007. [PERSON] and [PERSON] [17] used the LCA to assess three types of houses in the United Kingdom (UK): detached, semi-detached, and terraced, including all life cycle stages from house construction, use and to demolition after 50 years. From an energy point of view, [PERSON] et al. [18] applied two existing LCA tools--an economic input-output-based model and a process-based model--to estimate life cycle energy use in an example building. In addition, several reviews have been developed since 2015. [PERSON] and colleagues reviewed LCA studies at the neighborhood scale [19], whereas [PERSON] et al. [20] reviewed various LCA tools applicable to the building sector according to their functionality and different service life prediction models were also reviewed. [PERSON] et al. [21] also analyzed specific LCA building literature cases and different standards and frameworks. For instance, the comparison of four studies for structural concrete. Finally, [PERSON] and [PERSON] [22] focused on major challenges in building LCA, ongoing studies, and potential solutions to resolve identified issues. ACV was also applied to assess the environmental impact of construction and demolition of buildings. [PERSON] and [PERSON] [23] assessed three types of houses in Switzerland, considering direct impacts (use phase) and indirect impacts (material extraction, construction, and demolition). In this context, this study aims to go beyond the evaluation of the total energy impacts of the consumption of a building needed for EPCs. This research was conducted to propose a new evaluation system that could define a new energy/environmental performance metric from a holistic point of view. This evaluation model intends to be useful for encouraging and promoting environmental sustainability, taking into account a life cycle thinking approach. Therefore, in addition to the consumption of the electric and heating systems (direct energy), which are generally considered in this type of studies, this work also proposes the consideration of the energy impacts associated with the consumption of other material resources demanded during the operational phase of the building (indirect energy), i.e., the energy used in the production of water consumed. To calculate the contribution of this indirect energy impact as new variables for the energy performance certification, different buildings of university campuses were chosen as a case study. In particular, the buildings of the campuses of Universidad of Cantabria in 2015 were chosen because they present the same function during their use stage (education). However, the energy requirements depend on the type of academic degrees and the activities developed in each building.