Quantifying householder tolerance of thermal discomfort before turning on air-conditioner

Abstract In order to achieve comfort, or to remove discomfort, building occupants constantly interact with the indoor environment through various adaptive behaviors. The purpose of this study is to better understand the adaptive thermal comfort mechanisms by investigating the interrelationship between the indoor thermal environments, the expectation of the occupants, and their behavioral adjustments in residential contexts. Eleven households in South Korea participated in our field experiments performed during summer months (June, July and August) between 2015 and 2017. The indoor thermal environmental parameters, occupants’ subjective evaluations of thermal comfort, and their operational patterns of air-conditioners were monitored simultaneously. On average 1,512 datasets from each participating household and a total of 16,632 datasets were collected and analyzed. Our analysis focused on understanding both the temporal dimension (i.e. duration of thermal discomfort episodes) and the intensity of stimuli (i.e. deviation from the comfort zone) both before- and after the participants’ decision on the use of air-conditioners. The study proposes the constructs of ‘discomfort capacity’ and ‘comfort restoration’ as multi-dimensional indices to better understand the triggering mechanisms for household air-conditioner usage. Using these indices, the study quantified householders’ tolerance of thermal discomfort events before they resort to air-conditioning. The findings have practical implications in setting up dynamic control strategies that are more responsive to occupant real-time comfort demands.