Occupant Behaviour and Thermal Comfort in Small Commercial Buildings – EM Research: ASHRAE 2022

The occupant responses to thermal discomfort play a significant role in uncertainties associated with modeling and implementing building energy performance measures. In particular, for managers of small commercial building portfolios, a better understanding of the occupants’ interactions with the HVAC system is necessary for managing these uncertainties and reducing discrepancies between predicted and actual energy use. In Canada, these buildings are currently underserved by energy conservation and thermal comfort tools because of their dispersion and lower payback potential. Smart thermostats, along with their centralized data collection platform, provide an efficient and low-cost solution to collect massive amounts of data from a portfolio of these buildings that can be used to improve the understanding of the occupants’ behaviours and thermal comfort. This paper presents the results of a longitudinal study based on the smart thermostat data from a portfolio of more than 240 small commercial buildings located in Ontario, Canada. We analysed the occupant-thermostat interactions, as well as the HVAC schedules adjusted by the portfolio manager, to answer two main questions: 1) how occupants’ comfort decisions, specifically using thermostat overrides, are affected by various factors in small commercial buildings in which adaptive behaviours (e.g., opening windows) are generally very restricted, and 2) how the HVAC schedules, that are based on seasonality and occupants’ feedback, reflect industry-standard criteria for thermal comfort and affect the users’ interactions with thermostats. The results can help the portfolio managers to better understand the users’ interactions with the HVAC system under various circumstances and create efficient energy conservation programs while maintaining the occupants’ thermal comfort and organizational productivity.