A principal purpose of heating, ventilating, and air-conditioning is to provide human comfort. The primary factors that directly affect comfort are temperature, humidity of the environment, air speed, noise, their variation, and personal parameters of metabolism and clothing insulation. Air temperature alone is not the only determinant of comfort and should not be expected to correlate under all conditions.
Comfort is a driving factor to making better learning environments.
The most commonly used index of comfort is air temperature, but a number of other factors are also involved making the physical aspects of any environmental situation complex. Factors vary widely from one case to another and with time, the next and may be variable with time and the physiology of the human body. In addition, students and teachers respond differently to the same temperatures. Variations of the indoor environment include heat loss, heat gain, humidity, air movement, ventilation methods, ventilation rates, noise, and vibration. Typical heating and cooling temperatures for different school rooms are listed below.