Exploring digital twin interfaces for occupant-building interaction to enhance personal comfort and energy efficiency

• Introduce occupant-centric digital twin interfaces for comfort and energy efficiency • Explore multidimensional interfaces for occupants' dynamic contextual needs • Advocate a human-in-the-loop approach for responsive, occupant-centric DT systems • Anonymity significantly increases participant's willingness to share personal data Building occupants often have limited control over their environmental settings, which can lead to both dissatisfaction and inefficient energy use. This issue highlights the need for innovative solutions that not only improve environmental control but also actively involve occupants in the decision-making process. In response to these challenges, this study introduces an occupant-centric Digital Twin (DT) framework that presents environmental and building data to occupants for their informed decision-making. While the existing occupant-centric DTs were designed for facility managers as direct users, this study invites occupants as direct users of DTs and explores DT-based occupant-building interfaces. Leveraging the versatility of DTs, this study proposes three distinct user interface (UI) types, person-based, object-based, and recommendation-based controls, and investigates their impact in terms of user satisfaction, situation-dependent preferences, and data-sharing willingness. The test involved 120 participants and found that preferences for different UI types varied significantly depending on occupants’ contexts. Furthermore, participants expressed a strong preference for having the ability to switch between or mix different control types based on their current needs and context. In terms of participants' attitudes towards data sharing, participants were more willing to share data when they understood the benefits and were assured of anonymity. These findings provide insights into how to transform DT systems into occupant-building interfaces that enhance personal comfort and energy efficiency through context-aware occupant engagement.