The definition of comfort

Thermal and hygrometric comfort

Thermal comfort depends on:

  • physical parameters: air temperature, mean radiant temperature, relative humidity, air speed, atmospheric pressure;
  • external parameters: activity affecting metabolism, clothing;
  • organic factors: age, sex, individual physical characteristics;
  • cultural and psychological factors.

In addition, there are varying degrees of acceptance of so-called uncomfortable situations according to social and environmental conditions. The experience of a prolonged period of discomfort can lead to some environmental situations being considered "normal" when in a different context they would be judged uncomfortable. In a highly developed civilisation like our own we have come to expect a high degree of comfort.

Il comfort termico e igrometrico



Air temperature

26 °C

20 °C

Relative humidity

30 % < U < 60 %

30 % < U < 50 %

Air speed

0.1-0.2 m/s

0.05-0.1 m/s

Actual temperature

20-22 °C

16-18 °C

Tab. 1. Average limits for what are considered optimal hygrothermal conditions (Melino C. 1992).