You’ve probably heard this before: “Running a gas furnace during the winter may keep you warm, but it also dries out the air.” Since winter conditions are already drier than the rest of the year because more moisture has solidified out of the air, this can create serious problems for a house. Low humidity makes it harder to keep warm, which means running the furnace even more often. Low humidity also creates potential health problems by drying up sinus membranes, and it can cause damage to wood and painted surfaces.
But is it true that a gas furnace lowers indoor humidity?
The answer isn’t a straightforward one.