TECHNICAL NOTE
A. Air temperature
Air temperature has the most direct effect on thermal comfort. The temperature level at which people feel comfortable
depends on activity levels, clothing, age and natural body temperature, which varies from one individual to another,
and on seasonal temperatures.
B. Humidity level
Relative humidity (RH) refers to the moisture content in the air, expressed as a “%”. Buildings with low RH can lead to
dryness and throat irritations. RH below 40% is acceptable for short periods only. Conversely, high humidity makes the
environment “stuffy”. More importantly, it can contribute to the development of bacterial and fungal growth, especially in
sealed buildings.
C. Air movement
A certain amount of air movement around the human body is essential for thermal comfort for a light level of activity such
as bowling. The required level of airflow depends on the air temperature and humidity. Typically, it is recommended that
the air movement rate be maintained at 0.2 to 0.3 m/s.
1
Healthy heating educational resource site. (2013). Human comfort and health requirement. Retrieved 5 April 2013, from
2.4
Comfort level
Thermal comfort
There are six major factors that determine thermal comfort
1
:
Read more at:
Online thermal comfort calculator
Healthy heating educational resource site. Online thermal comfort calculator. Retrieved 5 April 2013, from
Environmental
factors
Personal factors
• Air temperature
• Humidity
• Air movement
• Radiant temperature
• Activity
• Clothing
Figure 28 Six factors determining thermal comfort
2
The basics
Hong Kong Green Building Council 61
