Development and Demonstration of the Operational Sustainability Index (OPSi): A Multidimensional Metric for Building Performance Evaluation

In promoting sustainable cities and societies, it is essential to accelerate progress from sustainable building design to sustainable building operations. One of the most effective ways to achieve this is by establishing a uniform metric that enables performance comparison across buildings of similar types and functions, both regionally and globally. This study develops and demonstrates the concept of the Operational Sustainability Index (OPSi), based on the integration of indoor environmental quality (IEQ) and energy utility quality (EUQ) models, as an important tool for holistic performance evaluation. The OPSi is applied to three cases: LEED-certified and non-certified dormitory buildings, LEED-certified and non-certified event buildings, and two pre-millennium multifamily housing units occupied by different genders. Across the various OPSi dimensions, LEED-certified buildings consistently outperformed their counterparts, and the multifamily housing unit occupied by male residents generally outperformed the one occupied by female residents. Additionally, LEED-certified buildings were found to exhibit greater climate resilience. This research offers policymakers and researchers flexibility in applying either less stringent or more stringent dimensions of the OPSi metric during implementation. It also contributes to addressing longstanding criticisms of green certification schemes for their limited capacity to measure post-certification operational performance. Future studies applying the OPSi concept on a broader scale are encouraged, and the potential for developing smart technologies to support this endeavor is discussed.