Single or double wall stove pipe

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mj5001

Member
Oct 15, 2011
160
United States
I have no safety issues and no that the single wall obviously is hotter to the touch than double wall. I know also that double lasts much longer.

BUT, don't you lose some valuable heat with double wall? Would using single put more of your stove's heat into the room?
 

Todd

Minister of Fire
Nov 19, 2005
9,357
NW Wisconsin
Unless you have a short chimney which could reduce draft or a long run over about 8' of stove pipe I'd go with single wall.
 
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nate379

Guest
I would say it depends on the stove. On a good EPA stove your flue temps aren't going to be very hot and it's heat that you probably want being used for creating draft.
 

Dakotas Dad

Minister of Fire
Mar 19, 2009
1,502
Central Kentucky
Double wall lasts no longer than single wall.

The purpose of the outer wall is simply a heat shield, whether you need to keep heat in to keep the flue warm, or to reduce clearances to combustibles.

But once the flue burns or rots through, it's done.
 
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naehring2000

New Member
Feb 12, 2012
67
North Shore, MA
I went with double wall because of clearance issues and a short chimney, I would say if you don't need it don't use it. It's also a lot more expensive than single wall.
 

webby3650

Master of Fire
Sep 2, 2008
11,001
Indiana
Dakotas Dad said:
Double wall lasts no longer than single wall.

The purpose of the outer wall is simply a heat shield, whether you need to keep heat in to keep the flue warm, or to reduce clearances to combustibles.

But once the flue burns or rots through, it's done.
Not true, double wall has a Stainless Steel inner wall, in normal conditions, it will never wear out.
 
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oldspark

Guest
webby3650 said:
Dakotas Dad said:
Double wall lasts no longer than single wall.

The purpose of the outer wall is simply a heat shield, whether you need to keep heat in to keep the flue warm, or to reduce clearances to combustibles.

But once the flue burns or rots through, it's done.
Not true, double wall has a Stainless Steel inner wall, in normal conditions, it will never wear out.
Well I have 30 year old single wall that looks like new so guessing it will go another 30 at least, l will be in the grave before it is.
 
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webby3650

Master of Fire
Sep 2, 2008
11,001
Indiana
With an EPA stove, the heat that comes off the pipe isn't a substantial amount. Unless the stove is wide open, there's not much heat coming off of it, there is enough to cool the flue though. When I clean a flue that has double wall, it's much cleaner, often very little build up. If it's not needed for clearance reasons, I wouldn't bother with it due to the expense. If you go with single wall, get the 22ga factory crimped pipe, it will last many,many years.
 

webby3650

Master of Fire
Sep 2, 2008
11,001
Indiana
oldspark said:
webby3650 said:
Dakotas Dad said:
Double wall lasts no longer than single wall.

The purpose of the outer wall is simply a heat shield, whether you need to keep heat in to keep the flue warm, or to reduce clearances to combustibles.

But once the flue burns or rots through, it's done.
Not true, double wall has a Stainless Steel inner wall, in normal conditions, it will never wear out.
Well I have 30 year old single wall that looks like new so guessing it will go another 30 at least, l will be in the grave before it is.
So i guess you have an all vertical run? Or 22 gauge pipe?
 
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oldspark

Guest
My stove pipe is not all that cool during the gas off phase, I like to have it around 300 surface temp for the most part, 600 or so on start up and reload.
 
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oldspark

Guest
webby3650 said:
oldspark said:
webby3650 said:
Dakotas Dad said:
Double wall lasts no longer than single wall.

The purpose of the outer wall is simply a heat shield, whether you need to keep heat in to keep the flue warm, or to reduce clearances to combustibles.

But once the flue burns or rots through, it's done.
Not true, double wall has a Stainless Steel inner wall, in normal conditions, it will never wear out.
Well I have 30 year old single wall that looks like new so guessing it will go another 30 at least, l will be in the grave before it is.
So i guess you have an all vertical run? Or 22 gauge pipe?
24 gauge with 2 90's
 

webby3650

Master of Fire
Sep 2, 2008
11,001
Indiana
oldspark said:
webby3650 said:
oldspark said:
webby3650 said:
Dakotas Dad said:
Double wall lasts no longer than single wall.

The purpose of the outer wall is simply a heat shield, whether you need to keep heat in to keep the flue warm, or to reduce clearances to combustibles.

But once the flue burns or rots through, it's done.
Not true, double wall has a Stainless Steel inner wall, in normal conditions, it will never wear out.
Well I have 30 year old single wall that looks like new so guessing it will go another 30 at least, l will be in the grave before it is.
So i guess you have an all vertical run? Or 22 gauge pipe?
24 gauge with 2 90's
Extraordanary!
 
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oldspark

Guest
Might have something to do with dry wood and not smoldering the fire.
 

WES999

Minister of Fire
Jan 12, 2008
1,047
Mass north of Boston
I went with Simson DVL double wall. I had plenty of clearance and could have used single wall.
My chimney is a little on the short side and it has an offset so I figured the double wall would be a good idea. Drafts fine no problems.

I do think DW should last longer, the inside is stainless steel, the single wall on my basement stove is only 4-5 years old and has some corrosion on the inside. I vote for DW.
 

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firefighterjake

Minister of Fire
Jul 22, 2008
19,298
Unity/Bangor, Maine
MJ5 said:
I have no safety issues and no that the single wall obviously is hotter to the touch than double wall. I know also that double lasts much longer.

BUT, don't you lose some valuable heat with double wall? Would using single put more of your stove's heat into the room?
I use my woodstove to heat the house . . . and the stove pipe to simply let the waste gas out of the house.

I mean sure . . . there may be some heat gain from single wall vs. double wall . . . but in my own case my house is plenty warm with the double wall. I think if most folks size their stove right and run their stove right the heat gain from single wall vs. double wall will not matter a whole lot.
 

webby3650

Master of Fire
Sep 2, 2008
11,001
Indiana
WES999 said:
I went with Simson DVL double wall. I had plenty of clearance and could have used single wall.
My chimney is a little on the short side and it has an offset so I figured the double wall would be a good idea. Drafts fine no problems.

I do think DW should last longer, the inside is stainless steel, the single wall on my basement stove is only 4-5 years old and has some corrosion on the inside. I vote for DW.
Just curious, why did you elbow at the stove? It's more common and would draft a bit better if the elbows are at the ceiling box. I'm glad it's drawing good for you.
 

WES999

Minister of Fire
Jan 12, 2008
1,047
Mass north of Boston
Just curious, why did you elbow at the stove? It’s more common and would draft a bit better if the elbows are at the ceiling box. I’m glad it’s drawing good for you.

I figured it would be a little easier to clean. The brush can goes straight down until the very end, then it would make the jog and come out in the stove.
 

Ken45

Minister of Fire
Feb 21, 2008
545
southern Ohio
I elected to go all the way with double wall, figuring that it would keep the temps higher and less creosote.
 
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oldspark

Guest
Well I only have about 53 inches of stove pipe so no way in hell am I going to pay for double wall, your set up will dictate if you need it or not.
 

Slow1

Minister of Fire
Nov 26, 2008
2,677
Eastern MA
Glad to read this debate... I'm in the process of deciding for myself here as I consider my upgrade from FV to PH. I have single wall now but I know I may have marginal draft at times. I added 3' to the top of my chimney that solved some downdrafts at startup and possible backpuffing the first year with the FV so I know I'm on the edge for the FV. I haven't discussed with WS yet - probably should of course. But I wonder just how much difference (if any) it could make to swap out the approx 4.5' of single wall pipe in the house. On one hand it seems it is too little distance to matter, but this is the hottest part of the flue gas exit and when I clean the pipe it is the only part of the chimney system that really has any real buildup so I know that there is some cooling going on here. IF I am going to do this, this is the time to do it - once the PH is in place I sure don't want to re-do anything!
 
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oldspark

Guest
Slow1 IMHO 4.5 feet wont amount to a hill of beans for draft, that short of single wall pipe should not be that cool at all unless you happen to be one of those with a setup that has a cooler flue, if you monitor your flue temps that one thing should tell you if you need double wall but for 4 feet I think it is a waste of money.
 

Slow1

Minister of Fire
Nov 26, 2008
2,677
Eastern MA
oldspark said:
Slow1 IMHO 4.5 feet wont amount to a hill of beans for draft, that short of single wall pipe should not be that cool at all unless you happen to be one of those with a setup that has a cooler flue, if you monitor your flue temps that one thing should tell you if you need double wall but for 4 feet I think it is a waste of money.
With the FW, I have a thermometer about 2" above the stove. I engage the cat at about 300* and it generally cruises at around 250* at high end, then falls from there - bulk of the time spent around 220*.

External is all ClassA exposed to the elements. I get icicles hanging off my cap when it is colder that fall of when I reload.

So - am I one of those with a cooler flue?
 
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oldspark

Guest
I think cat stoves run with a cooler flue correct, the question would be how much are you going to gain by only 4.5 feet of DW pipe, not much I bet, short runs of single wall pipe have little effect on the cooling of the flue.
 
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oldspark

Guest
I will add if you are willing to spend the money and you think you need it by all means put it in, just dont listen to the hype of the single wall pipe does not last long, I have seen sites that say you hae to change it out every few years and that is just some one who knows nothing about wood burning. If you have to change out your pipe that often you are burning with out a brain, I dont think even the cheapest pipe wont burn out that quick.
 
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