The objective of an index is to summarize a complex situation, where a series of variables (thermo-hygrometric quantities and variables related to the subjects: metabolic activity, degree of clothing and mechanical performance) interact with each other, by obtaining a synthetic number that is objective and comparable. Different indexes apply to different types of thermal environments. The indexes used can be various, but when the goal is to preserve the health of the occupants in the workplace, it is necessary to use indexes regulated and approved by the various national regulations.
In recent years, the assessment of the microclimate and in particular of thermal comfort has also been used as one of the elements to define the energy efficiency of buildings. Optimizing energy consumption according to the thermohygrometric comfort produced by the thermo-technical system and the architectural elements. The study of microclimatic parameters helps to regulate systems, such as air conditioning and heating systems, to reduce energy expenditure as much as possible, ensuring maximum living comfort.
