Abstract
This work presents a multi-criteria classification system considering multiple, conflicting and incommensurate evaluation aspects influencing energy efficiency in school buildings. The multi-criteria ELECTRE TRI method is used to classify energy performance of school buildings into categories of merit using the IRIS software. The alternatives under evaluation are assigned to predefined ordered categories according to their absolute performance and not in comparison with the performance of other alternatives. Each alternative is assessed using reference profiles defming the boundaries of the categories in which the alternatives should be sorted. The model was applied using a set of performance indicators obtained in the framework of a research and development project aimed at assessing the energy performance of a sample of Portuguese school buildings. IRIS allowed inferring robust conclusions by indicating the range of categories for each alternative, considering the decision maker's preferences, captured by the parameters of ELECTRE TRI. (C) 2017 The Authors. Published by Elsevier Ltd.

Abstract
The main goal of this paper is to present a set of well-defined and structured procedures to establish guidelines for the application of an integrated assessment of energy performance and indoor climate in schools. Increasing the knowledge about how energy is consumed in schools is a way to enhance the awareness of school managers (board of directors) about the importance of improving energy efficiency and reducing energy costs. The proposed methodology helps to identify major energy consuming equipment in school buildings and potential energy conservation measures. The assessment of indoor climate identifies potential corrective measures to problems related to indoor air quality and thermal comfort, also supporting the study of further energy conservation measures associated with ensuring environmental quality. Results of a case study showed that the expected energy consumption reduction is about 11.2% due to a better usage of daylighting and 4.5% due to the reduction of fresh air flow rates, while extending the ventilation operation time. In addition, there is a considerable non-calculated potential for energy savings and improvement of indoor environmental conditions in school buildings, promoting students and teachers productivity and wellbeing.