The effect of real-time context-aware feedback on thermal comfort and heating energy use: A case study

Variable occupant behavior is now being recognized as a significant factor in determining overall building energy use. Therefore, prompting correct energy behaviors represents a social, environmental and economic challenge of today. Real-time feedback can constitute a solution to this challenge. However, there is still a lack of knowledge and empirical proof to support their implementation. This paper investigates the effect of real-time context-aware feedback on occupants' adaptive behavior, perceived environmental control and thermal comfort. We report results from a six-week winter field study, with in-depth monitoring using environmental, CO2 and motion sensors in 15 student rooms at a UK university. Subjective data were concurrently collected through questionnaires (thermal sensations, clothing levels and adaptive responses). In the last three weeks of the experiment, students were provided with real-time feedback through a dedicated smartphone application. From a preliminary analysis of the results it emerged that a decrease of radiator and room temperatures were achievable without affecting the comfort of occupants. Students felt having a greater control over their thermal environment and, consequently, this greater control was able to mitigate their thermal expectations and offset discomforts due to the lower temperatures. This study supports the idea that saving energy does not always mean sacrificing occupants’ environmental satisfaction.