Meeting thermal needs of occupants in shared space with an adjustable thermostat and local heating in winter: An experimental study

[Display omitted] •The concept of thermal needs was proposed for analyzing thermostat-use behaviors.•Subjects selected 18.5–20 °C indoors with local heating devices and 21–22 °C without.•In shared space, every 1 °C increase indoors reduced 10%-20% of thermostat-use rates.•Thermal needs were more related to cool-sensation reduction than to set-point changes.•Thermostat-use behaviors in shared space finally met the needs of all subjects. Optimizing set-point temperatures of shared space is gaining significant research attention. However, few studies have tried to explain how occupants use an adjustable thermostat in shared space. The main objective of this study is to explore thermostat-use behaviors of occupants in shared space in winter. First, thermal need is defined as the final thermal environment that a person actualizes through employing enough control approaches. When a thermal need is met, a person does not further change the ambient environment. Thermal need can be regarded as the reference for optimizing indoor set-points. Herein, a series of tests was conducted in a two-person office room with an adjustable thermostat in winter, under different heating strategies (with and without local heating) and cool exposure before using thermostat (10- or 20-min cool exposure at 14, 16, and 18 °C, respectively). The obtained results indicated that (1) in shared space, the thermal needs of subjects with and without local heating were met with indoor temperatures of 18.5–20 °C and 21–22 °C on average, respectively. (2) Moreover, every 1 °C increase in indoor temperatures resulted in reduction by 10–20% of thermostat-use behaviors. (3) Further, every 10% increase in the cool sensation proportion led to a 10% increase in the thermostat-use behavior proportion. (4) And meeting thermal needs was more related to cool-sensation reduction than to set-point changes. (5) Finally, the set-point of shared space was mainly decided based on the thermal needs of the less-adaptive subjects than those of the more-adaptive subjects, for which the required temperatures were 1–3 °C lower than the former ones.