ark@alice.UucP (Andrew Koenig) (02/01/86)
> In my house we have gas heat, and it seems to dry out the air something > fierce. Why is this? I thought one of the products of the combustion > of the gas was water, so it shouldn't be necessary to put a pan of water > on top of the heater so I can wake up in the morning without my eyes > being dried shut. My housemates and some friends have made this same > observation, so I don't think it's co-incidence or my imagination. > > I can think of two possible reasons. First: by some mysterious mechanism, > water vapor is removed from the air. This seems unlikely since I don't > find condensation anywhere. Second: the air temperature is raised but the > amount of vapor in the air stays the same so the relative humidity drops. > The resulting RH is low enough to dry out the mucous membranes during > sleep. Perhaps I just wasn't paying attention, but I didn't notice this > drying out when I lived in a place with steam heat. In a normal gas furnace, the combustion by-products go up the chimmney. If you don't have a humidifier of some kind, you will indeed probably wind up with very dry air, for the second reason you mentioned.