High-resolution measurement of domestic hot water: Exploring individual tap patterns and preferences in single-family houses

As building insulation improves and space heating (SH) demand decreases, the relative share of domestic hot water (DHW) consumption in the total heat demand of buildings continues to rise. Further, the transition toward renewable energy systems creates a growing need for demand-side management (DSM) strategies, for which detailed knowledge of DHW usage patterns is essential. This study investigates high-resolution temporal and spatial patterns of DHW consumption in six Danish row houses to address existing knowledge gaps regarding tap patterns and preferences at individual draw-off points. High-frequency measurements were conducted at three hot water tap types (shower, washbasin, kitchen sink) across six households over two periods between May 2023 and April 2024, capturing flow rates and temperatures. Results reveal significant variations in comfort temperatures and flow rates between different tap types, with showers maintaining consistent temperatures around 40°C while washbasins and kitchen sinks exhibit greater fluctuations. Energy consumption profiles demonstrate characteristic diurnal patterns according to tap type and weekday, with notable differences between workdays and weekends. The study offers valuable insights into previously unexplored usage patterns, providing a foundation for more accurate DHW demand modelling and the development of flexibility strategies in future renewable energy systems.