coal fireplace to wood conversion

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erythrocebus

New Member
Dec 27, 2020
1
NY
We have a 'new' old house that has multiple coal fireplaces. They're all small, approx 18" wide at the back, 19" at the front. Is there any wood burning insert that could fit? I've been looking for a while without success. Grateful for any advice.
 

jetsam

Minister of Fire
Dec 12, 2015
5,236
Long Island, NY
youtu.be
We have a 'new' old house that has multiple coal fireplaces. They're all small, approx 18" wide at the back, 19" at the front. Is there any wood burning insert that could fit? I've been looking for a while without success. Grateful for any advice.
Before you go stove shopping, inspect the flues. If you can't fit an 8" round through them, it's going to be more than you want to bite off anyway- in that case just find a central location for a wood stove and do a new roof penetration.

If you can do a 6" insulated liner in the flues, the usual thing is to build out the hearth and put the stove in front of the old fireplace. You can either get a rear-vent stove or drill a new hole higher up in the chimney for the flue pipe.

Being inside an exterior fireplace is a crippling blow to a stove's heat output anyway, so don't worry about trying to cram a tiny camping stove with a 1 hour burn time in there.
 

DetroitReds

Member
Nov 16, 2018
27
Detroit, MI
We have a 'new' old house that has multiple coal fireplaces. They're all small, approx 18" wide at the back, 19" at the front. Is there any wood burning insert that could fit? I've been looking for a while without success. Grateful for any advice.
I had a similar situation. 19" or so at the rear and almost 24" at the front - but only 14" depth. I looked for basically years and could not find an insert narrow enough. I came to understand it would be disastrous to wider the opening of our masonry fireplace because it would weaken the lintel. After years of hemming and hawing I settled on just hearth mounted wood stove - and I have no regrets about that decision. I was initially concerned about it taking up too much valuable floor space, but the trade off for more efficient heat is totally worth it.
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logfarmer

Burning Hunk
Oct 25, 2015
210
Ohio
We have a 'new' old house that has multiple coal fireplaces. They're all small, approx 18" wide at the back, 19" at the front. Is there any wood burning insert that could fit? I've been looking for a while without success. Grateful for any advice.
Do you have the floor space to add a free standing stove like what Detroit did? You would be much happier with the free stander than a small insert!
 
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bholler

Chimney sweep
Staff member
Jan 14, 2014
24,013
central pa
Very nice!! Coming from a coal guy, fuel options are nice. Especially since those are becoming a rarity as people remove them from their homes.
Yeah but burning coal in an open fireplace? Very bad idea in a home is air dealing has been done
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
24,013
central pa
We still have one customer burning coal in an old victorian coal insert. I try to get them to stop every time I clean it
 

DetroitReds

Member
Nov 16, 2018
27
Detroit, MI
Lord, I would have assumed it was illegal to burn coal at home. With all the EPA regs?? At least, it should be!
All I could ever get away with is duraflame logs before, mostly for 'atmosphere'. Very happy with our setup now, perhaps even better than an insert (which wasn't an option). My last consideration was one of the longer stoves like the Jotul 602, 118 or Morso 2B and sticking it halfway in the existing fireplace. But I ruled that out for a number of issues.
 

Hoytman

Feeling the Heat
Jan 6, 2020
298
Ohio
If you would like to see the smoke from my neighbors outdoor wood boiler I’ll gladly take a picture. Modern wood stoves burn way more clean than that smoke dragon. Smokes this entire valley up and choked us all near to death.

I can also show you the heat waves coming off of my chimney ... crystal clear. I just fired up and she’s slowly settling in for the duration...110 lbs in the big Hitzer 354. If it stays at these temps I won’t touch her for likely 3 days, maybe more, except for a gentle shaking. If you need pictures just say the word.

My Democratic friends call it “clean coal”. We call it anthracite nut coal...hard coal.

Once the house acclimated to the stove settings she should settle in about 175F-225F at these 40F outside air temps and draft about .015 to .02 with this sorry 8”x8” chimney of mine. She should draft better with a smaller and more insulated chimney, but then I just have to hold her back more. Plenty of room to stretch her legs in this small house.
 
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bholler

Chimney sweep
Staff member
Jan 14, 2014
24,013
central pa
If you would like to see the smoke from my neighbors outdoor wood boiler I’ll gladly take a picture. Modern wood stoves burn way more clean than that smoke dragon. Smokes this entire valley up and choked us all near to death.

I can also show you the heat waves coming off of my chimney ... crystal clear. I just fired up and she’s slowly settling in for the duration...110 lbs in the big Hitzer 354. If it stays at these temps I won’t touch her for likely 3 days, maybe more, except for a gentle shaking. If you need pictures just say the word.

My Democratic friends call it “clean coal”. We call it anthracite nut coal...hard coal.

Once the house acclimated to the stove settings she should settle in about 175F-225F at these 40F outside air temps and draft about .015 to .02 with this sorry 8”x8” chimney of mine. She should draft better with a smaller and more insulated chimney, but then I just have to hold her back more. Plenty of room to stretch her legs in this small house.
As someone who has burnt coal and works on many coal.units every year including being at the top of the chimney while coal stoves are burning. I can tell you anthracite coal is not clean. The exhaust will burn your lungs and they will hurt for days. The sulfur turns to acid when it hits moisture. Clean coal plants are only clean because of the massive filtration systems on their chimneys.
 
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logfarmer

Burning Hunk
Oct 25, 2015
210
Ohio
If you would like to see the smoke from my neighbors outdoor wood boiler I’ll gladly take a picture. Modern wood stoves burn way more clean than that smoke dragon. Smokes this entire valley up and choked us all near to death.

I can also show you the heat waves coming off of my chimney ... crystal clear. I just fired up and she’s slowly settling in for the duration...110 lbs in the big Hitzer 354. If it stays at these temps I won’t touch her for likely 3 days, maybe more, except for a gentle shaking. If you need pictures just say the word.

My Democratic friends call it “clean coal”. We call it anthracite nut coal...hard coal.

Once the house acclimated to the stove settings she should settle in about 175F-225F at these 40F outside air temps and draft about .015 to .02 with this sorry 8”x8” chimney of mine. She should draft better with a smaller and more insulated chimney, but then I just have to hold her back more. Plenty of room to stretch her legs in this small house.
Looks like you got her dialed in buddy!
 

Hoytman

Feeling the Heat
Jan 6, 2020
298
Ohio
I never named it “clean coal” and I never said it didn’t have faults, I never said I didn’t have faults, I never told Detroit to burn coal in his fireplace. I said, fuel options are nice. I said those fire places are becoming a rarity ... implying it is nice to see someone keep and maintain the integrity and history of their home.
 

logfarmer

Burning Hunk
Oct 25, 2015
210
Ohio
As someone who has burnt coal and works on many coal.units every year including being at the top of the chimney while coal stoves are burning. I can tell you anthracite coal is not clean. The exhaust will burn your lungs and they will hurt for days. The sulfur turns to acid when it hits moisture. Clean coal plants are only clean because of the massive filtration systems on their chimneys.
You will have gases come from anything you burn, Hoytman was pointing out the chimney is not belching out plumes of smoke like his neighbors outdoor burner.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
24,013
central pa
You will have gases come from anything you burn, Hoytman was pointing out the chimney is not belching out plumes of smoke like his neighbors outdoor burner.
Very true. But given the choice I would rather be standing at the top of a woodburning chimney even a smoky one than a coal burner. But with modern stoves a wood burner should almost never be putting out visible smoke. And the exhaust gasses from wood are far less caustic.
 
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bholler

Chimney sweep
Staff member
Jan 14, 2014
24,013
central pa
I never named it “clean coal” and I never said it didn’t have faults, I never said I didn’t have faults, I never told Detroit to burn coal in his fireplace. I said, fuel options are nice. I said those fire places are becoming a rarity ... implying it is nice to see someone keep and maintain the integrity and history of their home.
I wasn't saying you did those things just giving my experiences. Btw I by no means think burning coal should be banned. But it isn't for me. And it has some substantial drawbacks.

It does also have some great advantages as well though.
 
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logfarmer

Burning Hunk
Oct 25, 2015
210
Ohio
Very true. But given the choice I would rather be standing at the top of a woodburning chimney even a smoky one than a coal burner. But with modern stoves a wood burner should almost never be putting out visible smoke. And the exhaust gasses from wood are far less caustic.
Yes I myself would not want to brush a chimney burning coal at that moment, I work in coal fired powerhouses and it is dirty! Yes modern stoves should be little to no smoke and wood pick a wood burning chimney over coal if they are “burning”.
 
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thecoalman

Member
Jul 18, 2008
37
Coal Country
coalpail.com
Yes I myself would not want to brush a chimney burning coal at that moment,
If you are exclusively utilizing anthracite coal in clay lined chimney you shouldn't have too. You aren't going to visibly see anything emitted from coal chimney.

Anthracite produces a fine grey fly ash most of which is going to accumulate in horizontal runs of flue pipe and the clean out for the chimney. Typically you would need to clean those once a year, if left unattended it will eventually block the flue pipe or thimble. Check the chimeny with mirror but you are mostly looking for other common issues.

Word of warning about mixing fuels, coal will dry creosote out and is quite an effective way to remove it. Problem is it will come down in big chunks potentially blocking the flue. The other potential issue is barometric dampers are often used on coal stoves, it's a perfect source for air if you have chimney fire from wood creosote.

I can't quote it but the EPA did some testing on one manufactures coal stoves, particulate emissions were much lower than modern wood burner. Even oil burner is likely higher but that is just guess by me based on experience. They were also warned about using it in literature because of the other issues with coal.
 
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nortcan

Burning Hunk
Sep 9, 2016
233
Quebec
I burned anthracite for a few years and it has many good points over wood burning. With 10 Lbs of antharacite I did 12 hrs at the same stove temperature and having the 3 floors warm, without touching the stove. One lighting for the all Winter, and many other plus. But : very hard on st-st chimneys, not as beautiful fire like wood, and here in Canada the anthracite became a lot too much expensive to buy. So came back to wood.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
24,013
central pa
If you are exclusively utilizing anthracite coal in clay lined chimney you shouldn't have too. You aren't going to visibly see anything emitted from coal chimney.

Anthracite produces a fine grey fly ash most of which is going to accumulate in horizontal runs of flue pipe and the clean out for the chimney. Typically you would need to clean those once a year, if left unattended it will eventually block the flue pipe or thimble. Check the chimeny with mirror but you are mostly looking for other common issues.

Word of warning about mixing fuels, coal will dry creosote out and is quite an effective way to remove it. Problem is it will come down in big chunks potentially blocking the flue. The other potential issue is barometric dampers are often used on coal stoves, it's a perfect source for air if you have chimney fire from wood creosote.

I can't quote it but the EPA did some testing on one manufactures coal stoves, particulate emissions were much lower than modern wood burner. Even oil burner is likely higher but that is just guess by me based on experience. They were also warned about using it in literature because of the other issues with coal.
I absolutely agree everything. The only issue I have is with the claims of anthracite being that clean. It really isn't as much about the particulate with coal as it is the gasses released. And being someone who ends up at the top of chimneys while they are running fairly often coal is my least favorite exhaust to be near. It really burns your eyes throat and lungs. Not that any are good for you but coal is the worst.
 
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bholler

Chimney sweep
Staff member
Jan 14, 2014
24,013
central pa
I burned anthracite for a few years and it has many good points over wood burning. With 10 Lbs of antharacite I did 12 hrs at the same stove temperature and having the 3 floors warm, without touching the stove. One lighting for the all Winter, and many other plus. But : very hard on st-st chimneys, not as beautiful fire like wood, and here in Canada the anthracite became a lot too much expensive to buy. So came back to wood.
Many of us only light one fire with wood once it gets consistently cool enough to heat constantly.
 

SpaceBus

Minister of Fire
Nov 18, 2018
5,782
Downeast Maine
If you are exclusively utilizing anthracite coal in clay lined chimney you shouldn't have too. You aren't going to visibly see anything emitted from coal chimney.

Anthracite produces a fine grey fly ash most of which is going to accumulate in horizontal runs of flue pipe and the clean out for the chimney. Typically you would need to clean those once a year, if left unattended it will eventually block the flue pipe or thimble. Check the chimeny with mirror but you are mostly looking for other common issues.

Word of warning about mixing fuels, coal will dry creosote out and is quite an effective way to remove it. Problem is it will come down in big chunks potentially blocking the flue. The other potential issue is barometric dampers are often used on coal stoves, it's a perfect source for air if you have chimney fire from wood creosote.

I can't quote it but the EPA did some testing on one manufactures coal stoves, particulate emissions were much lower than modern wood burner. Even oil burner is likely higher but that is just guess by me based on experience. They were also warned about using it in literature because of the other issues with coal.
For some time I really considered a coal stove, but the heavy metal emissions (the "other issues with coal") really turned me off. Oh, as Bholler mentioned the gasses emitted are also quite nasty and form sulfuric acid.
 

thecoalman

Member
Jul 18, 2008
37
Coal Country
coalpail.com
very hard on st-st chimneys,
If you are going to use coal an SS chimney or liner should be last resort with an expectation for short term of perhaps ten years if you are buying the high grade SS. It could be more or it could be less. A clay lined flue on the other hand is only going to deteriorate or need to be replaced for reasons other than the coal.

Most of the corrosion issues are related to the shut down at the end of the season. You get moisuture in everyhing and it reacts quite easily. On the other hand if it's running 24/7/365 it's not much of problem, the boiler in the house I grew up in had same galvanized flue pipe for 30 years but it was never shut off becsue it also produced domestic hot water.

It's obviously more common to shut them off especially if it's just small sove/stoker, you can use a solution of baking soda and water to clean flue pipes and the inside of the unit. That helps neutralize the acids.
 

thecoalman

Member
Jul 18, 2008
37
Coal Country
coalpail.com
For some time I really considered a coal stove, but the heavy metal emissions (the "other issues with coal") really turned me off. Oh, as Bholler mentioned the gasses emitted are also quite nasty and form sulfuric acid.
It's difficult to cite any data on this because all of the data is related to soft coal. Anthracite is niche market so it's largely been ignored. Anthracite has carbon content of 85 to 95 percent whereas the soft coal is typically much lower. If you are concerned about your personal health I wold suggest the wood is bigger issue because of the particulate issues. If your concerns are for the environment in general then wood is better than coal.

Even in close urban environment your neighbors wouldn't even know you were using coal. You might get a whiff of sulfur on warm and humid mornings when the wind is blowing right.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
24,013
central pa
If you are going to use coal an SS chimney or liner should be last resort with an expectation for short term of perhaps ten years if you are buying the high grade SS. It could be more or it could be less. A clay lined flue on the other hand is only going to deteriorate or need to be replaced for reasons other than the coal.

Most of the corrosion issues are related to the shut down at the end of the season. You get moisuture in everyhing and it reacts quite easily. On the other hand if it's running 24/7/365 it's not much of problem, the boiler in the house I grew up in had same galvanized flue pipe for 30 years but it was never shut off becsue it also produced domestic hot water.

It's obviously more common to shut them off especially if it's just small sove/stoker, you can use a solution of baking soda and water to clean flue pipes and the inside of the unit. That helps neutralize the acids.
It is much easier to just brush everything clean then spray it all down with wd40 to stop water from getting to the hydroscopic ash. With 316L rigid stainless pipe or heavy wall flex and proper maintenance you can easily get 20 years of use. And the acid eats clay liners as well just not as fast.
 
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