Developing key performance indicators for occupant-centric buildings using occupant feedback: A scoping review and methodological framework

The use of occupant feedback in smart building control and management has been shown to enhance indoor environmental quality and building energy efficiency. Despite this potential, its use in real-world building operations remains limited. To investigate its current applications and uncover barriers to adoption, we conducted the first scoping review to examine 1) how subjective feedback is collected through surveys in the domains of thermal quality and indoor air quality, and 2) how this feedback is subsequently transformed into actionable Subjective Key Performance Indicators (SKPIs) across various application contexts. Our findings revealed significant inconsistencies in survey design, survey deployment, and SKPI computation, even within similar use cases. This highlights the absence of standardized and systematic approaches to SKPI development as a critical obstacle. In response, we proposed a comprehensive four-step framework outlining key factors requiring standardization throughout the SKPI development process and discussing the state-of-the-art recommendations and debates in the literature. We then demonstrated how the framework can guide SKPIs development by considering these key factors with an example related to fault diagnosis in air handling units. Lastly, the major challenges associated with the SKPI developments and future directions are discussed, emphasizing the need for advancement of validated and robust scales, occupant sampling methods, and exploring applications in fault detection, diagnostics, and building energy flexibility. This paper highlights the untapped potential of SKPIs and establishes a methodological foundation for their development and application in smart building management and controls.