An Evaluation of the Environmental Payback Times and Economic Convenience in an Energy Requalification of a School

The majority of Italian schools (70%) were built in the absence of any legislation related toenergy efficiency, and therefore have very low energy performance due to aging or poor quality ofconstruction. An energy retrofit of this building stock is needed to meet the current European goalson greenhouse gas emission reduction. The retrofit is also needed in order to guarantee adequatecomfort levels in indoor spaces and good conditions for learning and educational activities, that areoften not reached in poor quality constructions. This work presents the results of an interdisciplinarystudy related to the energy requalification of a school located in Ostia, near Rome in Italy, built in the1960s with a steel structure and Eternit infill. The scope of the analysis is to verify the economic andenvironmental effectiveness of four proposed retrofit interventions concerning the replacement offixtures and the installation of an insulating coat. The current thermal transmittance of the walls wasevaluated through thermofluximetric measurements conducted in situ; dynamic simulations wereperformed to determine the current energy performance and the energy performances following thefour proposed retrofit scenarios. Energy and carbon payback times were evaluated (by means ofthe life cycle analysis (LCA) approach) and the economic value was determined for each of the fourproposed retrofits, using a probabilistic approach. The results show that the replacement of windowsis the most convenient intervention from all points of view. The study provides evidence that anassessment of schools’ energy retrofits should include both economic and life cycle aspects.