A smart environment is a physical space where smart devices/technologies are applied to continuously sense the occupant's daily living activities or health condition. Recent years have witnessed the application of smart environments to support independent living for elderly people or for people with chronic conditions. Nevertheless, most of the projects have been exclusively designed to support instances of single occupancy. In an effort to move beyond the scenario of a single occupant within a smart environment, this paper investigates the feasibility of using thermal sensors to detect the presence of multi-occupants and to track and visualise their motions. Results indicate that the use of thermals sensor can detect multi-occupancy, including moving subjects in addition to static subjects. The system developed demonstrated the ability to track up to 5 occupants, although mistrackings were found to occur when the individuals were apart after they stayed closely together.