Occupant behaviour has a strong influence on building performance (e.g., energy consumption, emissions, comfort). Therefore, it has been in the focus of scientific research for many years. IEA EBC Annex 66 (2014-2017) provided a sound framework for experimentally studying and modelling different behavioural actions, including the implementation of these models into simulation platforms. However, design and building operation practice shows that many of the models do not adequately represent the manifold human interactions with a building, and that there is little guidance for designers and building managers on how to apply occupant behaviour knowledge and models in standard practice. IEA EBC Annex 79 continued tackling these topics with emphasis on the following objectives:

• Improvement of knowledge about occupants’ interactions with building technologies. A specific focus will be on comfort-driven actions caused by multiple and interdependent environmental influences which were not yet covered by existing models.


• Deployment of ‘big data’ for the building sector as the availability of various data related to occupants’ behaviour in buildings increases rapidly. A special focus was on new modelling strategies to represent occupant behaviour in an improved manner.


• Sustainable implementation of occupant behaviour models in building practice by developing guidelines and preparing strategies for applying occupant behaviour models during building design and operation. Focused case studies should demonstrate the implementation of new models in different design and operation phases.

As these three objectives spanned over a wide scope of scientific and practical questions, the work of Annex 79 was divided into four subtasks under which a variety of activities were launched to address different related topics of occupant behaviour.

Looking at relationships and interdependencies between different indoor environmental parameters and their impact on perception and behaviour, findings clearly confirm that

• occupants' expectations with regard to indoor-environmental conditions do influence their interactions with buildings and their systems, and


• such interactions influence, in turn, the energy performance of the built environment.

There are several gaps in knowledge on occupant-related topics, specifically in the theoretical foundations of i) human behaviour in buildings, ii) buildings' user interfaces, and iii) ontologies for representation of occupants in computational applications. It also became obvious that a truly interdisciplinary approach involving representatives of physical and human sciences is necessary to cover the complexity of the topic, and a concerted effort should be taken to more actively involve professionals (engineers, architects, building operation specialists) in future research and development.

As an important output a comprehensive reflection of the state of the art of occupant behaviour in buildings has been provided which revealed multiple challenges and deficiencies in related studies, including various methodological shortcomings. This can serve as a robust and useful foundation for continued research and education in this essential area, particularly for a next generation of occupant representations to be integrated in computational applications (building information modelling, building performance simulation). Findings also suggest that more intuitive and effective user interfaces for buildings and their systems are needed to support successful comfort-driven occupants' interactions and thus reach their satisfaction with building performance. This is particularly true for older adults’ ability to use their spaces as desired and ultimately impacts aspects of their comfort, mobility, safety etc.

The work on deployment of ‘big data’ for the building sector showed that data-driven models have gained prominence in recent years and become the most widely utilized modelling approach, possibly due to the abundance of sensor-generated data and the availability of thorough statistical and machine learning software environments and programming languages. In order to maximize the potential of data-driven models, the establishment of a common data collection vocabulary or ontology is proposed, promoting data reuse and facilitating meta-analysis across different building types, sample sizes, and countries of origin. Additionally, providing occupant-related data in a standardized data model creates the opportunity to apply the data as inputs into the energy simulation tools.

For this purpose, an extended Brick schema appeared suitable for a standardized data structure as it provides a semantic framework to describe the various aspects from a building's structure to behavioural details of occupants, along with their relevant data. An important aspect is the availability of open data for modelling and simulation. In this view, separating data collection from data usage for research has to be considered. Finally, a variety of different modelling approaches were applied and tested for understanding and predicting occupant behaviour in building simulation, as well as for occupant-centric control.

A major output in this context was an occupant behaviour (OB) ecosystem of tools, datasets, guidelines, and methodologies. Specifically, a guideline for OB data collection and clear and transparent documentation of OB models was derived and published as a separate deliverable of the Annex. Furthermore, several OB datasets were collected and compiled in the ASHRAE Global Occupant Behaviour Database. It contains 34 field-measured datasets on different building occupant behaviours collected from 15 countries and 39 institutions across 10 climatic zones. A valuable addition was the Occupant Behaviour Library (OBLib), after several OB models had been gathered in GitHub. OBLib is a web-based platform for deciphering the details of the machine learning models trained from the data of the ASHRAE Global Occupant Behaviour Database.

Further work focused on integration of occupant information and application of occupant behaviour models in the building design process. An investigation of modelling tools and techniques regarding guiding and promoting occupant-centric building designs revealed that occupant behaviour integration into building performance simulation faces various adoption barriers. Studies showed an apparent disconnect between OB research and design practices as they were mainly at the proof-of-concept stage and lacked implementation and validation in actual buildings. A fundamental requirement for performing occupant-centric building design is establishing an effective mechanism to communicate occupant-related assumptions among project stakeholders. For this purpose, an information exchange platform is needed that is accessible to all design team members in order to establish an integrated design process. Furthermore, codes and standards should be updated because current occupant-related assumptions tend to be simplistic and are rarely dependent on design. These simplistic assumptions neglect the fact that building design affects occupant behaviour, which in turn affects building performance.

Theory and principles of occupant-centric design were brought to application through the presentation of seven real-world case studies. Major findings were that

• performing occupant-centric design requires information to be shared effectively among design stakeholders,


• occupant-related assumptions can influence the outcomes of design parametric analysis and affect the levels of comfort in buildings,


• occupant participation in the design process is useful in accurately representing occupants’ presence and behaviour, and


• post-occupancy data collection is critical for continue improvement of operations and improving future building designs.

The research also identified several ways that building energy codes could be elevated with regard to occupant behaviour. Recommendations are to

• add prescriptive requirements that relate to occupancy,


• update schedules, densities, and other values based on recent field studies,


• incentivize buildings with greater flexibility towards different occupancy schedules, and


• introduce occupant modelling requirements.

Further, a framework called ‘occupant-centric design patterns’ (OCDP) was developed which is compatible with building information management (BIM) systems and building performance simulation (BPS) tools. By linking with BPS and BIM it is integrated into the information exchange happening between team members with different disciplinary backgrounds, supporting collaborative initiatives from a technical perspective. Finally, a Bayesian networks (BN) structural learning approach was adopted to synthesize populations of occupants in a multi-family housing case study. Results show that the BN approach is powerful in learning the structure of data sets and should be further elaborated in future research.

With regard to building operation, research focused on real world implementations of occupant-centric control and operation (OCC). OCC involves the sensing of indoor environmental quality and various occupant-related data and feeding this information directly back to the control system to optimize for both operational efficiency and occupant comfort. Rather than impose conditions on occupants, OCC is an occupant-in-the-loop approach that seeks to provide optimal and personalized conditions. For a systematic approach with regard to data collection and control strategies, a categorization was suggested relating to presence/absence of occupants, to occupant counts, and to occupant activities – all at system/building and zone/room levels, respectively.

The work also revealed that the inclusion of OCC in building operation will result in a fundamental role change for building operators, including expanding their expertise into advanced technology integration, communication, and education. However, training and knowledge is necessary to properly apply these technologies. It is also necessary that organizations value their use and understand the benefits they present in supporting operators' work.

An important output in this context was a classification for occupant-centric operations case studies. It consists of a multi-level structure addressing

• observation- versus intervention-based studies,


• human- versus system-related studies, and


• further sub-categories for differentiating occupant actions or system occurrences.

Additionally, a repository of OCC case studies was set up, offering a platform for presenting key information about practical implementations of these strategies in real-world scenarios.

Finally, future methodological expansions of OCC were investigated which include

• the clustering of tailored personalized models for demand-response programs in the residential sector,


• a more comprehensive approach to comfort that includes occupants’ health, well-being and productivity,


• integration of occupants into the decision loop through different approaches, e.g., collecting qualitative data by surveys or interviews, allowing manual control within an automated OCC environment or feedback systems.  OCCs should aim at modulating operation around their inputs to reduce energy waste and dissatisfaction, and


• new ways of collecting direct occupant feedback, such as using smart phone or watch applications for continuous and real-time data collection instead of making inferences from historical building automation systems’ data.

To leverage the multidisciplinary project team, cross-subtask activities that involved multiple research areas were performed. One major output was the advancement of agent-based modelling (ABM) for integration with building performance simulation to evaluate the impact of occupants on building design and operation and vice versa. Further, an activity on human factors and ergonomics focused on employing methods that are well established in other interactive system domains, to design buildings that meet the physical, physiological, and psychological needs of human operators. A database of consumer-focused building control interfaces was developed.

Finally, one of the major efforts of Annex 79 is a book on 'Occupant-Centric Simulation-Aided Building Design', which is aimed at researchers as well as advanced designers. It provides theoretical and practical means to bring occupants and their needs into the centre of the building design process. The book also summarizes well the achievements of Annex 79 which not only contributed to new fundamental scientific knowledge in the field of multi-domain environmental exposure and the impact on buildings' occupants but also to new data-driven modelling approaches based on machine learning to integrate occupant behaviour in building performance simulation and occupant-centric control. Further, strong advancements in implementing occupant behaviour into the design practice were demonstrated by suggesting the enhancement of standards, to review the design process itself, and to integrate models into the digital design and simulation environment. And finally, the consideration of occupants in building operation and control as a further approach to implement occupant behaviour in building practice was successfully shown with different activities.