Revisiting thermal comfort in the cold climate of Darjeeling, India – Effect of assumptions in comfort scales

Abstract

The determination of comfort condition in any thermal comfort research is based on the subjective evaluation of thermal environment by the respondents. The use of multi-point categorical thermal sensation scales for the subjective evaluation is based on the assumption that these different points are equidistant and the central value coincides with the midpoint of the scale. However, recent studies have shown that the perception of the respondents towards these scales does not always follow these assumptions. A two-stage research for thermal comfort was conducted, first using a discrete 7-point ASHRAE thermal sensation scale and secondly, free positioning of these verbal anchors of the thermal sensation scale on a 100 mm line with the subjects of a same institutional building. Results showed that the comfort temperature varied significantly between different seasons. The subjects did not consider the verbal anchors of the sensation scale to be equidistant, neither the midpoint of the scale coincided with the thermal neutrality. An adjustment in the Griffiths’ equation is hereby proposed to include these differences in perceptions regarding the thermal sensation scale.