# single wall stove pipe into double wall stove pipe



## ramack (Aug 2, 2011)

Because of clearances to combustibles the way I am first thinking of running pipe from my stove to a ceiling support is:

Out of the stove use single wall stove pipe to a double wall tee stove pipe.  Then attach the double wall stove pipe directly to the ceiling support.

I'm looking at using MetalFab hardware.  The ceiling supports come with an adapter to single wall stove pipe, I don't find any listing for a similar double wall adapter.  However in the installation manuals, they show single and double wall being used between the stove and ceiling support.

Will single wall stove pipe fit into a double wall tee?

My other option is a heat shield.  Is it allowable/acceptable to fasten a heat shield to a sheet rock wall in order to reduce the required clearances?

Do I need to run all single wall or double wall from the stove to the ceiling support, or can it be a mix of the two?


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## skinanbones (Aug 2, 2011)

In Canada you have to use either single or double wall, you can't mix them together.  to reduce clearances to the ceiling a sheetmetal sheild spaced 1 inch off the ceiling will reduce clearances up to 67% agian Canadian codes.  There are also sheild kits out there that go directly on single wall pipe and they have a 50% reduction.


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## soupy1957 (Aug 3, 2011)

If my stove allowed it, I'd use double wall pipe, just on principle.

As for clearances and the "why" of it all..........I'd put as much fire-retardant material and heat shielding as I could, just because of the fire potential.  Overkill is my motto when it comes to safety.

-Soupy1957


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## firefighterjake (Aug 3, 2011)

Kinda thinking along the same lines as Soupy . . . not sure why you wouldn't just run all double-wall pipe to the transition piece where it then becomes a Class A chimney.


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## Wood Heat Stoves (Aug 3, 2011)

You can't mix single and double wall pipe. If double wall would meet your clearances, then just run the double wall pipe from the stove to the ceiling support. Another option is to use single wall pipe with a UL listed pipe shield on the area where you need the clearance reduction. You can also protect the wall for clearance reduction. Follow NFPA211 and any local codes.

http://woodheatstoves.com/free/NFPA211.pdf


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## ramack (Aug 3, 2011)

firefighterjake said:
			
		

> Kinda thinking along the same lines as Soupy . . . not sure why you wouldn't just run all double-wall pipe to the transition piece where it then becomes a Class A chimney.



Because I tend to do things the hard way, ha!

I'm leaning more toward the double wall stove pipe in order to K.I.S.S.  I was initially wanting to use single wall pipe to radiate and capture as much heat in the exhaust as possible.  Last night I was looking at the heat exchanger that go in-line with the exhaust, and came across an article, which in brief stated that they don't really work because the exhaust temp. in most cases is too low.  In addition, that if the exhaust temperature is hot enough for the heat exchanger to work effectively and efficiently there is something wrong with the inlet or outlet piping. 

Maybe these types of heat exchangers are good for barrel stoves etc.


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## SteveKG (Aug 3, 2011)

Whether you use the two different pipes, in the long run, you will be better off with one or the other. If it were me, I'd use the double-wall. I used to use single inside the house to save money on the cost of the pipe. Sometimes, though, you have to buy an adaptor for single-to-double connection. Sometimes you don't. The adaptor will cost. For ease of use, installation, and to create less brain damage in the long run, go with one or the other. 

From my experiences, or a couple of them: I had to replace my single-wall a few times. I have not [yet, anyway] had to replace any double. Labor and hassle and another purchase to buy new pipe. Before long, you've spent as much on replacing single as you would have buying double in the first place. 

Second, there really is, as you suggest, a lot of additional heat to be harvested due to radiation from single-walled pipe. Absolutely. However, you are also cooling your exhaust and in some cases that will affect, negatively, the draw and/or efficiency of your chimney operation. You may also find increased creosote deposits in your chimney as the cooler exhaust travels up. This is more work and can even be a safety issue in some cases. So. For the heat gained from the single-wall pipe, you might be paying for it somewhere else. No one can blame you for wanting to maximize your BTUs from your fuel. Sometimes, the heat lost is simply part of the cost of staying warm. Sort of analogous to some engines which throw more fuel into a cylinder than will burn so as to cool down the cylinder. Fuel "wasted," but an engine that isn't damaged from overheating.


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## firefighterjake (Aug 4, 2011)

ramack said:
			
		

> firefighterjake said:
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I would go with all double wall until you get to the Class A when it connects in the ceiling . . . simpler and safe.

As for the heat loss . . . you will no doubt not get as much heat off the double wall pipe vs. single all . . . but honestly with a newer stove you will gain the bulk of your heat from the stove itself and not the chimney. In my own case I have a 1,800 square foot two story Cape that I heat almost entirely with my woodstove (with double wall and an outside Class A chimney) . . . temps are plenty high enough (typically low to mid 70s depending on where you are in the home) . . . again the heat for the house is mainly coming off the woodstove and not the chimney.

As for those heat exchangers, such as the Magic Heat or Miracle Heat . . . the whole time I have been here I can only think of one or two folks who were staunch advocates of these . . . and the biggest proponent who often would write pure gibberish is no longer here. Perhaps the best argument against these devices on the newer EPA stoves is that they lower the stack temp which can affect the draft . . . and cause creosote to form more easily with the lower temps in the stack. Again . . . make your heat in the stove, not the chimney. As you noted . . . there may have been a time and place for these devices . . . with some cruder built stoves where a lot of heat was going up the chimney . . . but I would argue against these with the newer stoves.


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## shawneyboy (Aug 4, 2011)

firefighterjake said:
			
		

> As for those heat exchangers, such as the Magic Heat or Miracle Heat . . . the whole time I have been here I can only think of one or two folks who were staunch advocates of these . . . and the biggest proponent who often would write pure gibberish is no longer here. Perhaps the best argument against these devices on the newer EPA stoves is that they lower the stack temp which can affect the draft . . . and cause creosote to form more easily with the lower temps in the stack. Again . . . make your heat in the stove, not the chimney. As you noted . . . there may have been a time and place for these devices . . . with some cruder built stoves where a lot of heat was going up the chimney . . . but I would argue against these with the newer stoves.




+ 1


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