Optimisation of Passive Energy Renovation Strategies in Residential Buildings for Life Cycle Global Warming Potential Reduction and Cost-effectiveness

Abstract The European Union (EU) regulations claim an efficient evaluation of the building renovation processes, highlighting the quantification of the life cycle carbon and cost-efficiency, towards the carbon-neutrality targets. The integration of the life cycle thinking (LCT) in the environmental field – by the life cycle assessment (LCA) – and in the economic field – by the life cycle cost (LCC) – are the most promising methodologies for the required evaluation. Based on this, the study aims to optimise passive energy renovation strategies in residential buildings to achieve efficient life cycle carbon reduction and optimal global warming potential (GWP) and cost-efficiency. For this, the research employs the “PARARENOVATE-LCT” tool as a new approach for the parametric enviro-economic evaluation of energy renovation strategies in residential buildings with LCT. As a working methodology, firstly, we define the evaluation scope, case study and life cycle inventory (LCI); secondly, we evaluate each of the 245 scenarios composed by all the combinations of different types of intervention in façade, roof and windows; and thirdly, we conduct the multi-objective optimisation in terms of optimal life cycle GWP reduction and cost-efficiency. The multi-objective optimisation performed by the Pareto method identifies 17 optimal strategies. The results show that the maximum GWP reduction strategies do not coincide with the maximum cost-effectiveness strategies. Therefore, more than half of the GWP can be reduced by some strategy, but with medium cost-effectiveness; however, the strategies with the highest cost-effectiveness reduce around one-third of the climate impact. Graphical Abstract