ABSTRACT
Thermal comfort is often defined as ‘that condition of mind which expresses satisfaction with the thermal environment’ (ASHRAE, 1966; ISO 7730, 1984). It is convenient to have such a generally agreed definition as it saves laborious and insoluble arguments over semantics and emphasizes that comfort is a psychological phenomenon, not directly related to physical environment or physiological state. An understanding of why a person reports thermal comfort (or discomfort) or related feelings of warmth, freshness, pleasure and so on, is complex and not known. That thermal environments affect such feelings is easily demonstrated as are the consequences of not achieving thermal comfort, when humans will complain, health and productivity can be affected, morale can fall, and workers may refuse to work in an environment. For this reason, for almost all of the twentieth century, and often before, there has been an active interest in research into the conditions that produce thermal comfort. This interest and associated debate has continued with vigour into the twenty-first century. Emphasis has not been on understanding why people report comfort or discomfort, but on what conditions will produce thermal comfort and acceptable thermal environments. That is for a group of people, what human thermal environment (in terms of the interaction of the six basic parameters) will produce comfort and what will be the effect, in terms of thermal comfort and satisfaction, of deviating from these conditions?
