The operational and maintenance (O&M) phase of built environments accounts for nearly 80% of total building costs, with many buildings consuming about 30% more energy than necessary. Despite the use of Building Management Systems (BMS) to coordinate subsystems, significant inefficiencies persist.

Digital Twins (DTs) offer a promising approach to improve operational performance, yet their adoption in the built environment remains limited. Existing DT implementations often depend on integrating Building Information Modelling (BIM) data with dynamic sensor streams, introducing interoperability challenges and multiple integration layers for bidirectional communication.

This paper presents MetamEnTh, an object-oriented metamodel that encapsulates both static and dynamic building data within a DT. MetamEnTh embeds behaviours for modelling and acting on data to influence system states and introduces interfaces for API-based integration with building systems.

Two real-world use cases—the Webster Library at Concordia University and a mixed-use building in Ludwigsburg, Germany—demonstrate MetamEnTh’s potential to enable dynamic, real-time control and enhance energy efficiency in built environments.