We have a 1950's house on the east coast and want to convert our fireplace which we haven't used from a wood burner to gas logs. There is a gas stub in the firebox that just needs to be plumbed up to our service line.

We had a fireplace company come out to give us a quote and they are saying they can't do anything without basically redoing the entire inside of the flu and lining it to the tune of $12k. Their stated concerns are that the flu is oversized and may not draft perfectly, it's out of current code, the mortar is exposed and not in the best condition so gas vapors/moisture can damage it. Is this really a concern for gas logs?

Our original home inspector said he wouldn't be concerned at all about the condition if we switch to gas. The fireplace company was awfully salesy and I'm tempted to just get a plumber out to connect the gas line to the firebox and install gas logs myself. I'd love to save $12k but not if there is any real danger. Pics below are the best I could get.

I've had a gas fireplace since 2003 and the entire time I wished I still had a wood burning one.

Just shows, to each his own.

aggiedent said:

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I've had a gas fireplace since 2003 and the entire time I wished I still had a wood burning one.

Just shows, to each his own.

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Keeping it a wood burner would be ideal but I just don't have time to deal with it and I know it wouldn't get used more than once a week. Maybe when we don't have a toddler and infant in the house… Also we have a fire pit in the yard that gets used pretty much every weekend so I still get to scratch that itch.

We were stuck with a poorly done chimney at the house we are still in. My solution after research was to go with gas, but with vent-free instead of a vented system. I also wanted to have a legit back up source of heat. What I found was that almost all Texas homes go with vented systems as they look nicer but don't provide a lot of heat. From only what I am told, and not knowing first hand, most homes up north use vent-free due to the heat provided. The downsides of vent free are CO buildup, which is mitigated with a mildly leaky house (which we have) so the newer tightly built or foam sealed houses may not qualify. Also, I placed CO sensors on either side of the fireplace to cover that. But, my experience after 10 years of using one is that I never have had a CO sensor go off, and these units provide a ton of heat and can drive you out of the house if run on high for too long. During the snowmageddon the main central house stayed very warm. I am not an expert and that was only what information was provided to me but that may be an option, since a vent free only needs the flue barely cracked and doesn't depend as much on a proper chimney draw.
I think if you want looks only and want to run it when it is cool but not really cold then the vent free also not be for you as it can put out too much heat.
I can't speak on brands as ours is fair, went with a lower priced one with the only issue being a stubborn remote but provides great heat.
I'd also like for someone that is more knowledgable post info on vent free vs vented but that is the info I was provided.

Agree
We converted cone fireplace burning wood to propane gas logs
1st time Home Depot DIY w/plumber connection to bottles
Nothing but hassles and some danger
2nd time Fireplace Shop checked out flue, cap, found QUALITY logs w/no-power needed self-start switch, now connected to truck filled big tank
Heaven

These are no-vent-needed types BUT always vent flue a little for safety & more heat
then more open vent to exit smells and regulate temperatures.

18-inch can warm a big windows room ~1000sf when 40s outside, flue mostly open.

Advice:
Chimney sweep clean/advice + raincap?
Fireplace Shop logs installed w/warranty & call-back service options

Thanks. Do you recall the cost of your second system?

The fireplace shop also gave me a quote for an insert option which is the ventless unit. The quote was about $6500 for the unit and install, plus $1700 to connect the gas line, and another $2k because they still insist the flu needs to be relined, which doesn't make sense to me. I would also have to get an electrician to run electrical to the firebox as the units they install require dedicated power. All in would run around $11-12k which seems ridiculous.

fishnvet said:

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We were stuck with a poorly done chimney at the house we are still in. My solution after research was to go with gas, but with vent-free instead of a vented system. I also wanted to have a legit back up source of heat. What I found was that almost all Texas homes go with vented systems as they look nicer but don't provide a lot of heat. From only what I am told, and not knowing first hand, most homes up north use vent-free due to the heat provided. The downsides of vent free are CO buildup, which is mitigated with a mildly leaky house (which we have) so the newer tightly built or foam sealed houses may not qualify. Also, I placed CO sensors on either side of the fireplace to cover that. But, my experience after 10 years of using one is that I never have had a CO sensor go off, and these units provide a ton of heat and can drive you out of the house if run on high for too long. During the snowmageddon the main central house stayed very warm. I am not an expert and that was only what information was provided to me but that may be an option, since a vent free only needs the flue barely cracked and doesn't depend as much on a proper chimney draw.
I think if you want looks only and want to run it when it is cool but not really cold then the vent free also not be for you as it can put out too much heat.
I can't speak on brands as ours is fair, went with a lower priced one with the only issue being a stubborn remote but provides great heat.
I'd also like for someone that is more knowledgable post info on vent free vs vented but that is the info I was provided.

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My end game is to look at a direct vent fireplace. I'm planning on sealing and insulating my house as I renovate it, and replacing my furnace with a heat pump. I have no interest in a wood burning fireplace (I've literally never used the one I have) and I would like a backup source of heat.

I'm sure the ventless fireplaces are fine, but I would prefer vented, and given that I'm trying to tighten up the house, getting rid of one thing that would pull air for combustion would be nice.

Vent free are supposed to be more efficient/clean burning. I'm pretty sure they use interior air, but burn so completely that they don't require the exhaust to be vented to the exterior.

Typical vented draws air from the home, but exhausts to the exterior.

Direct vent uses a coaxial pipe or two pipes in the chimney to draw in exterior air and then exhaust the byproducts of combustion. They also have a built in blower to circulate the heat into the home.

A chimney sweep will clean out all the potential fire fuel/residues, then give you a 2nd opinion about a liner for gas-fire conversion (which I think would be zero).

The flue damper should be the same for propane and certainly is in my 80s all metal Preway cone fireplace that burned wood - when I was young enough to keep up with all that hassle - regardless of 50% more heat & free post oak limbs falling to ground.

The last & best was no insert fire, we simply replaced the cheap gas logs from HD/Lowes with pro-installed
EMPIRE 18" VFSR-18-4 that needs no power (self generating) solving the Power Outage Feb freeze problem.
american hearth williamsburg gas logs
Total install March 2020 $1360

Now looking for the plumber's cost to shoot a propane into this cone fireplace
$656 in 1995 that included gas logs #1 ($1282 in 2022 dollars) Happy me
Gas logs #2 was DIY HD/Lowes junk Not happy me
Gas logs #3 was 2020 (above) pro done Happy me

So without more evidence, thinking your to-do list is
Chimney Sweep for no fire threat & advice
Fireplace Shop for "vent-free" "no power Millivolt), gas logs selection, installation TBD & advice for plumber
Plumber (if any) gas supply as per Fire Shop needs
Shop install logs
You adjust flue as required for more heat/smells or more open
Light pilot Halloween, turn off Easter - if a pain and are rich, never turn it off

Millivolt ignition systems use a standing pilot light. This type of ignition system does not require any external power. Millivolt ignitions are also remote ready and can accommodate anything from a simple on/off wall switch to a programmable thermostatic remote.

Now for the guts
https://www.fixr.com/costs/chimney-repair
https://www.familyhandyman.com/article/before-hiring-chimney-sweep/
https://www.kcsweep.com/should-you-use-a-chimney-sealant/

Vent free won't put out much heat because they are a much much lower btu rating. If you have a vented fireplace and you go with a vented log set you will get a much better flame and much higher btu/heat output. Just compare the btu ratings to see what the highest output is. Of course with a vented set you need a chimney/flue.

I can't tell from pics if that chimney is okay or not.

Nothing beats a wood fire but damn turning my gas fireplace on from the couch with a remote will win me over every time.

If we're out at a ski lodge or hunting. Obviously wood.

AggieSam I thought with the vented logs they did have higher BTU but a lot of the heat was lost up the chimney, and they also burned through more gas per hour, but they did have a nicer flame appearance. With the vented they have lower BTU but are much more efficient at heating the house. All I know is my vent-free is rated for 38000 BTU and it will drive the heat in the house up so far you have to turn it off after a while, and the heat from the ceramic logs continues to heat for a couple of hours. I haven't seen that in relative's vented units.

Vent free (vent less/unvented) gas logs btu ratings are around 35000-38000

Vented sets start at 50000 and go up depending on the size of the burner.

You are correct that a true vent free fireplace pushes all the heat into the room but it's a much lower heat source. A vented fireplace does have a chimney and some of the heat will rise thru the chimney but if it's sized properly it should put out much more heat. The ceramic log set itself is designed to retain heat and push that heat out into the room.

That makes sense. I was also under the impression the vented sets burn more gas per hour. Is that correct? Mine is a miser and doesn't use much gas.

Yes. Lower btu, lower fuel consumption so vent free/unvented will use less fuel.

We turned our wood fireplace into natural gas fireplace last summer. Got tired of getting logs and cleaning it out. Had master plumber tap into the gas furnace line in the ceiling (two-story home), run it across across part of the ceiling, down the wall and into the fireplace. Drywall and painter fixed all the holes. Heat output feels the same.

Plumber $1600
drywall/texture paint $900
Gas logs $400
Gas log install $300