New insights into thermal comfort sufficiency in dwellings

Abstract

Domestic heating is a major contributor to energy consumption and must be minimised to achieve climate targets. Building on the concept of addressing the distinct heating needs of individuals and buildings separately, the Slowheat project implemented a three-year transdisciplinary real-world laboratory focusing on adaptive heating practices. This initiative involved 23 households in Brussels, Belgium, in a collaborative exploration of the sufficiency of heating: minimising heating while meeting needs for comfort. Starting with a mean thermostat setting of 19°C, participants reduced their indoor temperature to a long-term mean close to 15°C thanks to adequate warming of individuals through personal comfort systems, clothing and physiological adaptation. It resulted in a 50% reduction in heat consumption, without an increase in electricity consumption. These results exceed those of similar published experiments. The qualitative analysis highlights the multiple dimensions of social practices related to heating and underscores the key influence of control and comfort in sustaining significant temperature reduction. Policy relevance This paper presents the findings of the Slowheat project, which engaged 23 households in the Brussels-Capital Region over three years around the idea of ‘heating people, not buildings’. The subgroup involved in the quantitative analysis achieved a reduction in heating consumption close to 50%, without an increase in electricity consumption and with normalised indoor temperatures around 15°C. The results indicate that the potential for reducing energy consumption through changes in domestic heating practices is greater than previously documented in the literature, at least among climate-conscious and educated individuals. A co-creation approach was used. Key factors are highlighted that facilitated or inhibited the adoption of a sufficient heating practice. In doing so, it provides a framework for scaling up the Slowheat project. Furthermore, this shows the need for individuals to gain greater control over their indoor environments. Four dimensions of control are emphasised, including the crucial aspect of social norms, for which policy instruments may play a role.