# Can you make an old stove more efficient?



## brokenknee (Dec 7, 2012)

Has anyone tried adding tubes to an old wood stove to make it more efficient? A new stove is just not in the cards at this time and was thinking about welding some tubes to a stand and set it inside my firebox, this is an older wood furnace with a fairly good size fire box so I there is some room.

What size tubes would one use, how long, are there holes in the tubes, how close to the top and rear of the stove should they be located?

Any and all advice, opinions are greatly appreciated.


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## Woody Stover (Dec 7, 2012)

I'm sure there are more threads on this topic...

https://www.hearth.com/talk/threads/bullard-secondary-air-retrofit-project-complete.55033/
https://www.hearth.com/talk/threads/...er-stove-updated-with-2ndary-burn-idea.28006/
https://www.hearth.com/econtent/index.php/forums/viewthread/67238/


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## wkpoor (Dec 7, 2012)

brokenknee said:


> What size tubes would one use, how long, are there holes in the tubes, how close to the top and rear of the stove should they be located?


Yes it is possible to retrofit an old stove. Problem is answering all your questions above my take more time and money than a new stove already engineered and tested to perform as such.


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## brokenknee (Dec 7, 2012)

Woody Stover said:


> I'm sure there are more threads on this topic...
> 
> https://www.hearth.com/talk/threads/bullard-secondary-air-retrofit-project-complete.55033/
> https://www.hearth.com/talk/threads/...er-stove-updated-with-2ndary-burn-idea.28006/
> https://www.hearth.com/econtent/index.php/forums/viewthread/67238/


 
Thanks, a lot of good and interesting reading.


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## brokenknee (Dec 7, 2012)

wkpoor said:


> Yes it is possible to retrofit an old stove. Problem is answering all your questions above my take more time and money than a new stove already engineered and tested to perform as such.


 
I would not expect to make it as efficient as a new stove, just more efficient than it is. Reading some of the other threads that Woody provided I don't think the cost would be that much. I already have some of the material lying around. I burn 24/7 so I will most likely wait until spring to try this mod.


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## MnDave (Dec 7, 2012)

Do you run with a stovepipe damper?
They help slow down the heat loss up the chimney. Cost $3.

MnDave


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## brokenknee (Dec 7, 2012)

MnDave said:


> Do you run with a stovepipe damper?
> They help slow down the heat loss up the chimney. Cost $3.
> 
> MnDave


 
Nope, just the bi metal damper.


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## MnDave (Dec 7, 2012)

brokenknee said:


> Nope, just the bi metal damper.


I am not sure what the bimetal damper does but I am guessing it controls the air to the stove thermostatically by the sound of it.

This suggestion is to possibly help your stove efficiency at a very minimal cost and effort.

On my very first stove there was a stovepipe damper built into the first section of factory stovepipe. The stove had a thermostatically controlled fan but when I first started using the stove I wondered why it would take forever before the fan would come on (and there was no way to get it to come on manually).

Somehow I figured out that the stovepipe damper needed to be closed about halfway or so and the fan would come on in minutes. The stove really started to put out some heat once that damper was closed and the fan started running.

This was in a mobile home so the chimney was less than 8 feet. So even with a very small draft that stove damper really helped the output of the stove.

I don't know your draft situation but I think that these dampers help efficiency. Unless you have a super marginal draft in the shoulder seasons, a damper cannot hurt.

MnDave


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## etiger2007 (Dec 7, 2012)

I wouldnt do it, burn dry wood until you can get some money to buy one thats tested, keep that family safe.


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## wkpoor (Dec 7, 2012)

brokenknee said:


> I would not expect to make it as efficient as a new stove, just more efficient than it is. Reading some of the other threads that Woody provided I don't think the cost would be that much. I already have some of the material lying around. I burn 24/7 so I will most likely wait until spring to try this mod.


In a way thats what the Elm is. An old design retrofitted. Don't know how many trials before he settled on something he liked but after owning a certified EPA stove I can say his retrofit works just as good with great secondary burn.


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## brokenknee (Dec 8, 2012)

MnDave said:


> I am not sure what the bimetal damper does but I am guessing it controls the air to the stove thermostatically by the sound of it.
> 
> This suggestion is to possibly help your stove efficiency at a very minimal cost and effort.
> 
> ...


 
Yep, bi metal damper to control air intake. Draft OK but not great (14 foot chimney, 8" square tile). The stove did not have a damper when I bought the place and never really thought about adding one. Like you said they are cheap. I will add that to my list of things to do. Thanks.


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## brokenknee (Dec 8, 2012)

wkpoor said:


> In a way thats what the Elm is. An old design retrofitted. Don't know how many trials before he settled on something he liked but after owning a certified EPA stove I can say his retrofit works just as good with great secondary burn.


 
I am leaning on giving it a try. I really don't have much to lose. If I really mess it up it will give me a good reason to update to a real EPA stove.

Not going to happen at least until spring, can't afford to shut the stove down for any length of time.


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## brokenknee (Dec 8, 2012)

etiger2007 said:


> I wouldnt do it, burn dry wood until you can get some money to buy one thats tested, keep that family safe.


 
I don't really see how I would be putting the family in any danger. My welding skills are still pretty good. Went to welding school over 25 years ago, but never worked in the trade.

The furnace is not located in the main house, but a separate room off the (attached) garage. Heat is then ducted into the house over head. I know the whole system is not the most efficient, but it dose keep us warm even at -30* F.


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