# How big should my firebox be?



## horndog (Sep 20, 2012)

I've read in a couple of posts something about a formula for firebox size. Maybe because I'm new here (sorry I did look for it), I'm not sure where to look. I'm not sure sure how to arrive at the correct size. It looks like my smoker will be 14.7 cubic feet. Can anyone help me figure this out and how we actually determine the correct size and why.

Thanks much, John


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## sqwib (Sep 27, 2012)

Look in my signature

Pit Calc.


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## the smoker (Oct 7, 2012)

@SQWIB... I looked at the Pit Calc, are all of the figures that are needed on this sheet in inches? Cause the results that it is coming up with seem pretty big for the exhaust, vents, ports. Just seems odd to me, but I'm still learning and new at all of this.


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## joseph651 (Oct 7, 2012)

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__ joseph651
__ Oct 7, 2012






Horndog...I would agree with your thoughts.  My house is 3200 sq ft and my airtight wood stove which  the size 18"x26" with a 6" stove pipe that is 96" long heat my house throughout the winter.  I go through about 5 to  6 cords a year.  We heat our house only with this stove.  I am building a smoker that is a 8' propain tank that is 34" round.  My fire box is a 22" round  steel pipe that is 24" long.


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## ribwizzard (Oct 8, 2012)

The calculator is pretty darn close for everything , I would trust it. The only thing I dissagree with it on is the length of the exhaust pipe. 

On either a side firebox or reverse flow, the firebox should be about one third the size of the cooking chamber. If you tuck it up under the chamber, you can reduce the size somewhat, but I would not recomend it.


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## daveomak (Oct 8, 2012)

Horndog said:


> I've read in a couple of posts something about a formula for firebox size. Maybe because I'm new here (sorry I did look for it), I'm not sure where to look. I'm not sure sure how to arrive at the correct size. *It looks like my smoker will be 14.7 cubic feet. *Can anyone help me figure this out and how we actually determine the correct size and why.
> 
> Thanks much, John


John, morning.... 14.7 cu ft is about 110 gallons.... plug that number in the calculator....  

Calculation.... 0.7854 x diameter squared x length of tank = volume of the tank... (if in inches) / 1728 = cu ft x 7.48 = gallons....  

Dave


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## the smoker (Oct 8, 2012)

Yeah from looking at the calc, and the size of what my contraption is, I would agree about the 1/3 size for the burnbox, and that mine needs to be bigger.


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