Study on energy conservation of home appliances and equipment through questionnaires and measurement surveys in Japan

• Nationwide survey quantifies energy use of home appliances in Japan. • Rice cookers, dryers, and heaters identified as hidden energy-intensive devices. • Approximately 50% of households use home appliances and equipment to dry clothes. • Using a bathroom dryer to dry clothes can lead to heating of over 2 MWh/year. • Findings support extending building energy policies to include appliances. Climate change is a pressing issue that requires immediate action and calls for global efforts to conserve energy and reduce carbon dioxide (CO 2 ) emissions. A large proportion of energy consumption is attributed to houses, and the influence of home appliances is not negligible. However, regulations regarding energy conservation in houses apply only to attached facilities and do not consider related home appliances. Consequently, there is insufficient information on the actual situation regarding home appliances and equipment related to indoor environments, and measures to reduce power consumption are insufficient, leading to situations where occupants unintentionally use electricity. This study used questionnaires to assess the actual appliance and equipment usage conditions in Japanese houses. This study focuses on commonly overlooked appliances that consume a relatively large amount of electricity. Appliance usage varies widely depending on residential characteristics. For example, approximately 50% of households use home appliances or devices to dry clothes, mainly to avoid pollen and weather effects, and reduce the time and effort required for housework. Additionally, measurements and product surveys were conducted to determine the instantaneous power consumption and the amount of power consumed per use of home appliances. By integrating questionnaire and product survey results, the distribution of power consumption of electric heaters, bathroom dryers, and clothes dryers in Japanese houses was determined. These appliances were used frequently or for long periods in a certain percentage of houses and could reduce power consumption by switching to highly efficient devices.