Abstract
This paper summarizes and discusses the results of a survey to identify the conditions under which kotatsu was used and the date it was last used. The survey was conducted from April to July 2008. The total number of questionnaires was 1488. The following findings were obtained: 53.0% of respondents used kotatsu in the year investigated and 69.9% of respondents owned kotatsu. The usage rate of kotatsu was 56.8% for detached houses and 47.6% for apartments, while the possession rate of kotatsu was 76.8% and 60.3%, respectively. The date that kotatsu was last used was defined as that when 80% of the kotatsu users had stopped using kotatsu during the period of investigation. These dates of last use were different for different regions: May 3 in Mie, May 6 in Aichi, May 10 in Shimane, May 15 in Gifu and Saitama, May 23 in Tottori and June 15 in Nagano. The minimum outdoor air temperatures for the date of last use in Mie, Aichi, Shimane, Gifu, Saitama and Tottori ranged from 11.8 to 13.7℃ and that in Nagano was 15.6℃.
