Nowadays, wearable devices are increasingly worn by people which they provide a good opportunity to use such devices to improve indoor thermal environment control. This paper proposed an energy-efficient control method for the indoor thermal environment by occupants positioning and comfort range recognition using a smart bracelet. The smart bracelet measures people’s skin temperatures continuously, which is used to on-line learn room occupants’ thermal comfort ranges and recognise the thermal comfort states. The smart bracelet is also used to identify the trajectory and position of an object by the value of acceleration data provided by the inertial sensor. Then the positioning information and thermal comfort state information are used to achieve locally personalised thermal environment control, which could be both energy efficient and thermally comfortable. Experiments were conducted to verify the performance of the proposed control method. Experiment results show that the proposed control method has advantages in reducing user’s complaints of thermal discomfort and consumes 12.6% less energy than the traditional control method of giving temperature set-points by room occupants.