## 1 Introduction  
The development of the internet changed facilities and the built environment. Technologies and research disciplines enable the internet to reach out into physical objects is called the Internet of Things (IoT) [1]. The range of physical objects that are connecting to the internet is growing, and the world is becoming smart. With various definitions and meanings, _smart_ is defined by [PERSON] [2] as 'a system capable of learning, dynamic adaptation, and decision making based upon data received, transmitted, and processed to improve its response to a future situation. The system does so through self-detection, self-diagnosing, self-correcting, self-monitoring, self-organizing, self-replicating, or self-controlled functions. These capabilities are the result of the incorporation of technologies for sensing, actuation, coordination, communication, control, etc.' The more recent development of the Internet of Things (IoT) in smart buildings is even more important with blockchain [3; 4; 5]. Smart buildings are equipped with smart systems. Smart materials, sensors and metres within buildings gather data about building operation and management [6]. There are smart systems for maintenance, security, lighting, occupancy, energy and indoor climate. Smart systems offer an opportunity to support processes in the building, use resources more efficiently and contribute to attuning the building to changing demands [7]. Smart features interact with one another and the building users. The operational phase of a building is the most prolonged period of the life cycle of the building and is often managed by the facility department. The definition of facility management (EN 15221) is 'the integration of processes within an organisation to maintain and develop the agreed services which support and improve the effectiveness of its primary activities'. This research focuses on the benefits of smart systems for facility managers and the users of an office building. Reducing energy consumption and improving building efficiency are two reasons why companies choose smart systems [8]. The occupancy of a building has an enormous influence on the energy used in a building [9]. With sensors, the occupancy of the building can be measured. This provides insight into not only the energy use of the building but also the occupancy and building use of the users. With the data from the sensors, the organisation can optimise space management for buildings. Space management is critical because efficient use of space can reduce square metres and can lead to a better fit between workspace design and the tasks of the users [10]. The data from the sensors give insight into the employee work patterns regarding office rooms and areas. This can be used to make decisions about office layouts [11]. Numerous companies supply smart sensors. Verdantrix is an independent research and consulting firm with a focus on innovative technologies. It conducted a global study [12] on the suppliers of smart software and the best fit for customers. The study is based on live demonstrations and a survey with 16 market-leading suppliers. They also conducted interviews with facility managers from 15 companies to understand customer needs. The study on space management features concluded that there is a push to maximise the employees per building and that space management is an essential factor to buy smart software. Respondents said that software for space planning is already used. However, the current software gives insufficient data to support management decisions, and it is very precious to perform analysis. The study by Vendantix shows that there are gaps between the demand and the supply of the software. The exploitation is not optimal, and this implies that the potential benefits of occupancy sensing for the different users are not fully achieved in practice and that smart systems do not always deliver what they promise. This fuels the suspicion that the enthusiasm to adopt smart building features may be hype-driven and a form of corporate branding.