I did find a link but it says it was actually confirmed. Interesting because my memory is so different. It was a strange episode though, so I could have gotten it confused, probably because they were so convinced it wouldn't be true.
http://www.mythbustersfanclub.com/ht...nd_season.html
I don't have a fireplace and probably won't. It's still in the 90s here. But, I do know that a woodstove will heat the whole house and doesn't seem to suck air from anywhere. I've been in a house with a woodstove and OMG it is soooo hot.