Investigating the Effect of Psychological Factors (Colour and Light) on the Human Perception of Thermal Comfort - Case Study: Commercial Buildings in District 2 of Tehran

The thermal comfort analysis models specify the acceptable thermal condition such as temperature, humidity, and air movement. Personal, measurable environmental, and psychological factors affect thermal comfort. Psychological factors are often overlooked because they are difficult to quantify. These factors based on different hypotheses such as the hue-heat hypothesis affect the human perception of thermal comfort. The hue-heat hypothesis indicates the relationship between warm and cool colours and subjective evaluation of thermal comfort. This paper used a questionnaire (Actual Sensation Vote) to examine the association between these factors and thermal sensation, humidity sensation, and draught sensation. Totally 65 volunteers from commercial buildings in district 2 of Tehran answered the questionnaires. Cronbach’s alpha is calculated and showed the consistent reliability of the questionnaires. Results indicated that in winter, thermal sensation votes increase in hot spaces (warm colour and low lighting colour temperature) compared to two other spaces. Likewise, in summer, thermal sensation votes decrease in cold spaces (cool colour and high lighting colour temperature) compared to two other spaces. In addition, results clarified that discomfort sensation in the head, neck, and chest is more than in other parts of our bodies. Therefore, regarding thermal comfort, hot spaces are better in winter, and cold spaces are better in summer.