A case study discovering lock-in effects of culinary culture and behaviours on cooking energy use in Chinese homes

China’s rapid urbanization and industrialization have expanded building floorspace and contributed to rising carbon emissions in the building sector. An often-overlooked aspect of residential energy use is cooking, which this study examines through two longitudinal household case studies, combined with a questionnaire survey of 202 households. Monitoring results show that cooking accounted for 23% and 48% of total household energy consumption in the two cases, confirming its significant contribution to the residential carbon footprint. To further investigate the observed highly linear growth in cooking energy use in both households, a questionnaire survey was further conducted, revealing a lock-in effect correlating cooking energy with family life cycle (FLC) stages and habitual cooking practices, rather than with family size per se. To quantify this relationship, this study proposes a novel indicator, Cooking Energy Use Intensity (CookEUI), defined as the average daily cooking energy consumption (kWh/day). CookEUI ranges from 4.13 to 5.10 kWh/day for elderly and middle-aged couples, increases to approximately 6–7 kWh/day for two-generation households, and reaches 8.13–12.86 kWh/day for three-generation households with dependent children. Survey responses further indicate that cooking energy is strongly constrained by culturally embedded culinary behaviours. Our findings suggest potential solutions to reduce cooking energy use and emissions – such as alternative cooking appliances, cleaner energy sources, and community dining options – while respecting entrenched culinary culture, providing valuable insights for sustainable residential cooking practice and supporting efforts to reduce household carbon emissions.