An investigation of human thermal comfort and adaptation in naturally ventilated residential buildings and its implication for energy use in tropical climates of Ethiopia

A human thermal comfort study was conducted in naturally ventilated residential buildings of Jimma town, southwest Ethiopia. A field survey was undertaken in dry seasons (February 1 to May 31, 2020) of a warm temperate climate. In this study, 104 residential buildings were purposely selected and 430 residents, 213 (49.5%) male and 217 (50.5%) female participated. The subjective responses on the prevailing thermal conditions and adaptation methods were collected using the questionnaire. Measurements of indoor thermal conditions were undertaken using handheld digital instruments following ASHRAE class II protocols. In the study periods, the outdoor thermal data were obtained from the town's meteorological station. The neutral temperature was 20.4 degrees C and the comfort range of indoor air temperature was 14.6 degrees C to 26.3 degrees C. The study participants used simple environmental controls and personal adjustments to set indoor thermal comfort. Our study indicates that people in developing countries like Ethiopia can achieve thermal comfort with natural ventilation and hence less demand for energy-intensive mechanical ventilation. Further study on cooling/heating energy consumptions of households of developing countries is recommended.