Originally posted by amd
It's called relative humidity for a reason. Heating systems do not remove moisture - they simply increase capacity of it.
30F outdoor air is @ 60% RH is very dry when heated to room temperature for example. Newer homes have much less infiltration relative the moisture produced by occupants.
Homes with natural draft furnaces tend to be much drier - outdoor air has to displace what goes up the stack.
I would have thought that all hvac technicians grasp the concept of relative humidity. Guess not.
[Edited by amd on 10-27-2005 at 08:13 PM]
still does not explain why hot air furnace dries house out more than hot water boiler. both draft up chimney.