Effect of Humidity on Thermal Comfort in the Humid Tropics

This paper presents the main findings of the effect of indoor humidity on occupants ’ thermal com-fort in the humid tropics of Malaysia. An extensive field investigation was carried out in Kota Ki-nabalu city and the surrounding areas, located in East Malaysia. A total of 890 individuals were asked to complete a questionnaire. Measured indoor climates were also recorded. The survey was designed as cross sectional data collection. The present investigation found that the occupants were thermally comfortable at wide relative humidity range. The mean relative humidity corres-ponding to the optimum comfort temperature was close to 73%. Regression models failed to pre-dict accurately the effect of relative humidity on occupants ’ thermal perceptions. In addition, a quadratic regression model was developed for the prediction of the mean indoor relative humidi-ty based on indoor temperature. The suggested regression model can be used for an approximate prediction of indoor relative humidity when required