Establishing the Relationship between Occupants’ Thermal Behavior and Energy Consumption during Showering

Despite an increased awareness about energy conservation in the past decade, the energy consumed for water heating has increased by 7% from 2008 (17%) to 2018 (24%) in Hong Kong. A literature review on existing energy-saving technologies during showering showed that occupants’ behavior significantly impacted energy consumption. However, the exact relationship between them was not yet fully understood. Therefore, this study developed a mathematical energy consumption model to investigate the relationship between occupants’ behavior and energy consumption during showering. This relationship identified an effective energy-saving strategy in the shower without scarifying occupants’ thermal comfort. The main variables that influence energy consumption and thermal comfort in bathrooms namely air temperature, water temperature, ventilation rate, and water flow rate, were considered. It was found that among them, water flow rate and ventilation rate are the most and least influential variables, respectively, in energy saving. Therefore, the ventilation rate was suggested to be at least 0.03 kg·s⁻¹, and the water flow rate was meant to be lower than 0.15 kg·s⁻¹ (based on related requirements). These findings could help residential occupants and facility managers determine the optimal showering settings for thermal comfort, energy consumption, and environmental effects.