10. March 2021

Comfort level on the h-x-diagram

Room air in which we feel good

The state of comfort on the h,x diagram

Absolutely dry air does not occur in our atmosphere. It always contains a certain amount of water vapor. Moist air is therefore a mixture of dry air and an absolute proportion of water vapour. Depending on the temperature, the dry air is able to absorb a different proportion of water. In principle, warm air has a greater absorption capacity than colder air. The relative humidity results from the interaction of absorption capacity and temperature.

About the formula :

the percentage can be calculated or determined using the h,x diagram.

x = amount of steam present in g/kg

x s = amount of vapor in saturated air in g/kg

φ = relative humidity


state of comfort

Depending on the percentage of vapor in the air and the temperature of the air, there are prescribed conditions for each application.

According to DIN 1946, thermal comfort is given when the air temperature, air humidity, air movement and thermal radiation in the environment are perceived as optimal and neither warmer nor colder, drier or damper room air is desired.

DIN EN ISO 7730 defines thermal comfort as a feeling that expresses satisfaction with the ambient climate.


The state of comfort on the h,x diagram



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