Factor Analysis Focusing on Lifestyle Factors of Utility Costs for One-person Student Households in Tohoku Region of Japan before the Great East Japan Earthquake

Abstract

A questionnaire survey on both the lifestyle and energy consumption of 626 university students in Tohoku region was conducted in 2007 and 2008 to assess energy conservation behaviors and energy consumption in one-person student households. This study aims to clarify the influence of each lifestyle factor that would affect the energy consumption of one-person student households. Of the 626 respondents, 344 one-person households and 215 family households were analyzed via the method of quantification theory type I, as the explanatory variables were roughly divided into hard and soft factors. In this study, the hard factors are considered to be the age of the building, the space heating and cooling period, the set point temperature of space heating appliances, heat source of hot water supply, and the set point temperature of hot water in winter. The soft factors are considered to be the degree of action of the energy conservation behavior in the house, consciousness of global environmental issues, consideration for energy conservation in daily life, and the degree of energy conservation efforts. The following conclusions of this study were obtained: 1) It was found that the heat source of hot water supply and set point temperature of hot water supply in winter were important factors that have a great impact on the annual utility costs among the six hard factors used in the analysis in one-person student households and family households, respectively. 2) Space cooling period had clear association with the annual utility costs in one-person households, whereas space heating period had clear association with the annual utility costs in family households. 3) The annual utility cost of one-person student households was greatly influenced by how to use appliances and energy conservation efforts. 4) The tendency of the partial correlation coefficients of soft factors to be higher in family households than those of hard factors was stronger than that of one-person households. 5) Differences in energy conservation efforts and consciousness of global environmental issues among family households were greatly reflected in annual utility costs compared to one-person households. 6) The effect of the degree of action of energy conservation behavior in the house on the annual utility costs was found to be greater or comparable to that of the hard factors including how to use equipment in both one-person households and family households. 7) It was shown that the correlation with the annual utility costs is higher when considering not only hard factors but also soft factors in both one-person households and family households. 8) It is important not only to save energy, but also to confirm that the indoor thermal comfort is secured in one-person households. Since the number of one-person households is expected to increase in the future in Japan, the findings of this study are expected to be useful to promote energy conservation nationwide by developing energyconservation techniques for one-person households. At the same time, energy conservation measures should be developed that take into account the importance of lifestyle-related factors depending on the household type.