Originally Posted by
32t
The relative humidity is the amount of water in the air compared to what it CAN hold. The amount of water in the air does not have to change but the amount it can hold will change depending on the temperature. Heating dry air will just lower the relative humidity. A solution as you state would be to evaporate more water into the air such as using a humidifier. Or water pots on your wood/coal stove.
The reason that I brought up the moist air from the chimney as being from the combustion is because that is not "stealing" the water from your house or heated space. It is a separate act. So whether you use coal, wood, or LP the resulting low humidity is not because of your fuel used.