An innovative multi-stakeholder decision methodology for the optimal energy retrofit of shopping mall buildings

• Evaluation and ranking of feasible shopping mall energy retrofit solutions. • Intervention on HVAC, building envelope and renewables are considered. • Electric energy savings, net present value and discounted payback period are the KPIs. • Conflicting stakeholder interests are gauged in the comparative and regret analysis. • An uncommon solution demonstrates how competing interests affect compromise. With the European Green Deal, innovative strategies for building retrofits should focus on implementing advanced energy efficiency measures and exploiting renewable energies for the reduction of operational CO 2 emissions. The energy retrofit process of buildings typically involves several stakeholders with diverse and often conflicting interests, evaluating potential energy efficiency measures a multi-criteria decision-making (MCDM) issue that must consider different perspectives of various parties. This paper proposes a hybrid MCDM methodology that integrates several traditional approaches to robustly evaluate and rank feasible building energy retrofit interventions and applies it to the renovation of an existing shopping mall near Naples, Southern Italy. The building’s energy model is calibrated and validated using actual energy consumption data from bills, while the analyses of the building-HVAC system are conducted using the EnergyPlus dynamic energy simulation engine. The alternative retrofit interventions are assessed using three key performance indicators: electric energy savings, net present value and discounted payback period. The new hybrid MCDM approach is used to rank the solutions from the different perspectives of various stakeholders: policymakers and building tenants. This methodology enhances the robustness of the decision-making analysis by reducing method-related uncertainties and separately addressing different stakeholder perspectives. The results underscore the relevance of renewable energy sources in building retrofits, both from the energy and environmental standpoint. Moreover, stakeholder comparative and regret analyses reveal that no common solution exists for the mall retrofit and provide important insights into how competing interests affect reaching a compromise.