[Greenbuilding] flue gas thermometers, was firewood moisture content

Corwyn corwyn at midcoast.com
Sun Dec 18 11:20:56 PST 2011

On 12/18/2011 12:06 PM, Reuben Deumling wrote:
> I've corresponded with John Gulland and discovered his antipathy toward
> flue gas thermometers. To each his own. I love mine; wouldn't want to be
> without it for anything.
> Then I came across this passage on his site:
> "For most of the time a wood stove is operating, its flue gas
> temperature is either rising or falling. Anyone who says that you should
> aim for a particular flue gas temperature or even a range in temperature
> is _setting you up for failure because steady-state burning is almost
> impossible to achieve._"

For the most part I don't pay much attention to my flue as thermometer 
anymore.  I like to think that this is because I am more in tune with 
what the fire is actually doing.  I do think they are great tools for 
those who need them.  I would caution however that they do NOT provide 
absolute measures, but rather relative measures.  Every stove is 
different, placement of the thermometer varies, etc.  Look at the 
temperature when the fire is burning well, look at it when it is burning 
poorly, look at it when it is going nuts; from there, interpolate.

I also don't think 'steady state' is the holy grail of burning.  I don't 
*want* the fire to be at the same temperature when it has new logs in 
it, as when it has nothing but coals.  Those aren't even the same 
chemical processes.

Thank You Kindly,


Topher Belknap
Green Fret Consulting
Kermit didn't know the half of it...
topher at greenfret.com
(207) 882-7652

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