Key performance indicators for holistic evaluation of building retrofits: Systematic literature review and focus group study

Buildings are increasingly designed and constructed with state-of-the-art facilities. But without proper upkeep including timely implementation of appropriate retrofits throughout the operational stage, the facilities will not be able to perform to meet their intended purposes and the ever-rising user demands. Research on building retrofits has been widely pursued, but studies focusing on the identification of appropriate key performance indicators (KPIs) for holistic evaluation of building retrofits remain limited. To address this research gap, a mixed methods approach combining positivism and interpretivism was taken for a study. First, a four-stage literature review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method was conducted, which resulted in identification of 62 performance indicators that are applicable to evaluating building retrofits. Second, after consolidation and refinement the indicators underwent a focus group study. Grounded upon deliberation and shortlisting by the focus group experts, 19 KPIs were selected and the reasons for having those indicators excluded were revealed. The selected KPIs fall into four aspects: economic, environmental, users’ perspective, and health and safety, and their distributions by quantity are 37%, 26%, 26% and 11% respectively. Not only are these KPIs useful for evaluating the performance of building retrofits in practice for the betterment of a sustainable built environment, but the methodology of this study can also be taken in similar research to identify KPIs in other areas.