Absolute Humidity

Absolute Humidity is measured in grams of water per volume of air (grams per cubic metre [g/m³]). It is not temperature dependent and in the example above the absolute humidity would remain unchanged at around 6.4 g/m³, regardless of the temperature change.

Absolute humidity is a suitable measure if one is looking for sources or sinks of water in an environment where temperature is changing. If the absolute humidity is cycling during the day, eg, increases in a roof cavity as the temperature rises during the day. It could indicate that moisture is released by the building materials during the day and absorbed or condenses during the cooler nights.