Ondol Korea: Research paper: The effect where all pebble sleep environment goes mad to all ten physiological reactions of the human body

The purpose of this study was to investigate actual sleeping environments in Ondol rooms depending on the season. The experiment was performed on five healthy women. The bedroom environments using Ondol were measured in five cases(three apartments and two houses). The environments in bedroom, bedding temperature, skin temperature and thermal sensation were measured continuously through the seven days for each season in real life. This data of sleeping environments were analyzed in the view of seasonal variations and housing types. Annual average bedroom temperatures: 26.2~31.0℃ in apartments, 15.7~33.6℃ in houses. Annual average bedroom humidity: 48.3~82.1% RH in apartments, 64.9~87.0% RH in houses. During sleeping, temperatures of contact surfaces like sheets and under quilits ranged between 30.5℃ and 34.1℃ regardless of season or housing type. Annual average rectal temperature was 36.8℃ with no significant difference in season or housing type. In the point of thermal sensation, neutral temperature of the bedroom was 25.9℃ in apartments and 20.3℃ in houses. It was concluded that in spite of thermal environmental variations according to the seasons, skin, bedding and bedroom temperatures in apartments were better and more stable than those of houses. It is regarded that while houses are brick structured, apartments are steel-frame structured. Due to better insulation and air tightness, apartments were affected less from outdoor temperature and maintained higher room temperature than houses