What is a comfortable office temperature (2)
A comfortable office temperature doesn’t depend just on the temperature, there are other factors that come into play. These include the relative humidity, the temperature of surrounding surfaces and the speed of any air movements.
Craig Ryan of Johnson Controls has prompted this second posting with some good observations about humidity and comfort on my first posting on a comfortable office temperature.
The more humid it is, the higher the temperature feels. This is shown in the thermal comfort chart below.
thermal comfort diagram - humidity vs temperature
In climates which are always hot, or climates that are mostly cold, our bodies acclimatise somewhat to these conditions. The chart above is most appropriate for cooler rather than hot climates.
Moving air makes it feel colder. When its hot creating air movement (eg through fans) can mean that air conditioning systems can be set to provide higher temperatures than would otherwise be the case.
Radiant temperatures of nearby surfaces also make us feel warmer or colder. Because of this sitting next to a large window in winter may still feel cold even though the inside air temperature is 22 degrees Celcius.
By operating heating and cooling systems out to the limits of what is perceived to be a comfortable temperature significant energy and greenhouse gas savings can be achieved. Attention also needs to be paid to air movement and surface radiant temperatures.