Vented vs Non-vented Logs
LESLIE: Now we’re going to talk to Bob in Georgia who has a gas fireplace question.
Bob, how can we help you?
BOB: Yeah, hi. I recently moved into an older home. It has two rather small what were once coal-burning fireplaces.
TOM: Real tiny fireplaces.
BOB: And so they’re not very deep.
TOM: Right, mm-hmm.
BOB: We had somebody come out and look at them and they can’t fit either the vented or non-vented log. So I’ve been doing a little research on it and I’m just kind of wondering – like I realize that the vented logs are less efficient but the non-vented – can you tell me like do they put off a tremendous amount of moisture?
TOM: They absolutely do because natural gas is 80-percent water vapor. And so when you use an unvented fireplace, all of that moisture is being dumped back into the house. You know, the efficiency question is a very slippery slope. Depending on who you’re asking, you’re going to get an answer that benefits them. If it’s the fireplace manufacturers, they’re going to tell you that they’re more efficient. Personally, I don’t like the idea of taking any natural gas combustion any bigger than what my stove puts out and dumping it back into the house. I think it’s a really bad idea to do that. So I’m always going to vote for a vented, as opposed to a non-vented fireplace.
You know, in the years I spent in the home inspection business, Leslie, I used to inspect unvented fireplaces all the time and I was always impressed by the fact that, you know, typically, if you buy a piece of furniture or something, the warning label’s a little piece of cloth attached to the cushion. When you buy a fireplace, the warning label was stamped …
LESLIE: Is a booklet?
TOM: … stamped in metal, chained to the fireplace front. (chuckles) You know? Here’s a hint, folks. And if it’s still – I believe this is the case. But the last I checked, non-vented fireplaces were still illegal in Canada; they couldn’t sell them up there – and those people are pretty aggressive with energy issues – just because of the safety aspects.
BOB: Yeah, well here in Georgia, of course, it’s not going to get that cold. The vented would go right up the chimney, as opposed to saying a gas stove that runs a vent up the chimney and sits outside the fireplace itself.
TOM: Well, yes. I mean having a damper so that the chimney’s not open all the time. But remember, if you put a damper in, you have to remember to open it before you use the thing. Is your chimney lined?
BOB: No, it’s just brick.
TOM: Well, you really should have a liner. Because the other thing about gas venting is it’s acidic and if you don’t have a liner, you can start deteriorating the inside of that. A liner does not have to be expensive, especially with a gas fireplace. There’s basically a piece of liner that kind of looks like a – it looks like a dryer exhaust duct but it’s flexible and it’s made out of metal and it kind of unwinds from the bottom all the way to the top and it becomes a metal, stainless flue that goes all the way up on the inside, connects to a vent hood at the top and down to the damper at the bottom. So you really should have a liner for that.
BOB: Yeah, OK. Well, thanks.
TOM: You’re welcome, Bob. Good luck with that and hope you enjoy that fireplace this winter.