Humidity vs temperature

[scoobyru]

Hi all ,

Being a fridge guy for about 7 years now i always thought humidity would drop with temperature but from experience it seem this is not the case can any one explain why humidity seems to go up the colder a room gets or am i just on something ? i had a stulz installer tell me humidity goes up cooler room gets didn't explain why thought he was talking out hes behind to be honest it does seem true .

[Brian_UK]

You need to have a look at a psychrometric chart.

Put simply, warm air can hold within it a set amount of water vapour, cold air can only hold a reduced amount of water forthe same air volume.

You may have noticed that in full air conditioning systems the humidifier only really runs in the winter months. The cold outside air may have a relative humidity (RH) of 80% but when it is inside a heated building space the RH can drop to 30% - 40%.