Exploring the Energy–Water Nexus in Dishwasher Usage Behaviors of China’s Households: An Analysis Based on Questionnaire Surveys

With the rapid adoption of dishwashers in China’s households, the consequent growth in energy and water consumption presents new challenges for energy conservation, emission reduction, and water resource management in China. To address this, this study adopts the concept of the energy–water nexus to analyze the factors influencing dishwasher usage behaviors and quantifies the co-benefits of energy and water conservation through questionnaire surveys, establishing a household dishwasher energy and water accounting model. The findings reveal that dishwasher usage behaviors are influenced by dietary habits—greater oil usage in cooking leads to higher frequency of use and a greater tendency to select intensive wash modes, thereby increasing energy and water consumption. It is projected that by 2030, promoting energy-efficient dishwashers could achieve annual savings of approximately 390 million kWh of electricity and 4 million m3 of water. Furthermore, shifts in dietary habits offer significant potential for achieving co-benefits in energy and water conservation. Encouraging households to adopt low-oil cooking practices could yield additional annual savings of 5.14 billion kWh of electricity and 9.57 million m3 of water. Based on these results, this paper puts forward policy recommendations to facilitate the coordinated management of household energy and water conservation.