Decision-making for renovating the Mediterranean social housing: A practical approach through an interactive open access tool

• Parametric stock models and AI are implemented in multi-objective optimization. • Thermal comfort and economic costs are optimized by the NSGA-II algorithm. • Passive and operational optimal strategies are proposed to retrofit social housing. • A phased process with gradual and sequential renovations is proposed. • Partial renovation aligns energy with economic and social objectives in vulnerable homes. To achieve 2050 Climate Neutrality, building stock requires a multidimensional renovation process. This is particularly urgent in most vulnerable households, with higher exposure to climate change, where this procedure should focus on cost-controlled passive measures. Given the complexity of identifying optimal strategies, it is imperative to improve the retrofitting process of the social housing stock to enhance its energy performance guaranteeing health and comfort. For this, an interactive tool was developed focused on the case of southern Spain. Able to provide optimized combinations of energy retrofit strategies, using NSGA-II genetic algorithms and setting two optimization objectives: minimizing thermal discomfort and economic costs. The freely accessible tool was designed with practical and didactic approach to facilitate decision-making. The results obtained suggest the feasibility of implementing phase actions instead of a single large-scale intervention and show the tool’s ability to quantify the percentage of thermal comfort improvement achieves at each phase.