Just consolidating what others have said here...first, get humidity level up to around 50%. See if that helps your wife's problem. If not, look for "leaks" in stove and house. I've used a big fast-food softdrink straw to "sniff" the stove at doors and joints...including stovpipe up to thimble. Under certain conditions, I've had a slight backflow thru bathroom vents, etc., from outside. Finally, depending on outside temps, chimney, and burning unseasoned wood, you can get ice buildup in chimney that will reduce draw and can cause smoking...