120k btu

[Jleatherman7]

Hey guys, trying to look at some stove options. Can someone explain why a big box store stove, vogelzang ponderosa is rated for a max output of like 120k btu but a stove made by jotul is rated for only half of that but cost twice as much? Is the btu rating something I should really consider?
Thanks-Jon.

 

[bholler]

Hey guys, trying to look at some stove options. Can someone explain why a big box store stove, vogelzang ponderosa is rated for a max output of like 120k btu but a stove made by jotul is rated for only half of that but cost twice as much? Is the btu rating something I should really consider?
Thanks-Jon.

Btu output is definitely something to consider. But realize us stove co who makes vogelzang is not very reputable. So I wouldn't pay much attention to their specs.

And btu output really doesn't enter into the pricing. Jotul is a very high quality cast iron stove that will last a very long time. The us stove company stuff is cheap Chinese crap that won't last long.

There are some pretty good entry level stoves though. Sbi who makes drolet has some good cheap options. As does new England stove works.

 

[Jleatherman7]

Btu output is definitely something to consider. But realize us stove co who makes vogelzang is not very reputable. So I wouldn't pay much attention to their specs.

And btu output really doesn't enter into the pricing. Jotul is a very high quality cast iron stove that will last a very long time. The us stove company stuff is cheap Chinese crap that won't last long.

There are some pretty good entry level stoves though. Sbi who makes drolet has some good cheap options. As does new England stove works.

Thanks for the info. I would imagine the conditions to get that btu number would have to be almost perfect.
Maybe you could help me with another question.
I got an 1850s 2 story log home(1400sq ft above ground living space). Was told that we need a liner in the chimney but biggest I can go(if I’m lucky) is a 5x7 oval. Will that be sufficient for most stoves?

 

[kborndale]

Thanks for the info. I would imagine the conditions to get that btu number would have to be almost perfect.
Maybe you could help me with another question.
I got an 1850s 2 story log home(1400sq ft above ground living space). Was told that we need a liner in the chimney but biggest I can go(if I’m lucky) is a 5x7 oval. Will that be sufficient for most stoves?

Most modern stoves require a 6" flue.

 

[peakbagger]

Give me an induced draft fan on the stack and an air preheater with a FD fan on the grate and superdry dense wood and I could get a stove to glow and eventually melt into a puddle.

 

[NorMi]

UL 103 lists 97k BTU/hr /12.1 lbs wood/hr for 6" flue pipe, and 5x7 is about 15% smaller. In a stove that size, with <3cu.ft. fireboxes, 120k BTU/hr is silliness. Realistic maximums on 6" flue appliances are half that, and that's usually spread out over at least 2.5-3 hours. If you burn less than 10lbs/wood per hour it would be an equivalent safety spec, that's 82,450 BTU/hr more or less, which is still more than you should or would want to sanely burn in any wood stove that size. A max burn rate at 60k BTU/hr should come out to about 7.5 lbs wood/hr, and that's still cookin'.

 

[Jleatherman7]

UL 103 lists 97k BTU/hr /12.1 lbs wood/hr for 6" flue pipe, and 5x7 is about 15% smaller. In a stove that size, with <3cu.ft. fireboxes, 120k BTU/hr is silliness. Realistic maximums on 6" flue appliances are half that, and that's usually spread out over at least 2.5-3 hours. If you burn less than 10lbs/wood per hour it would be an equivalent safety spec, that's 82,450 BTU/hr more or less, which is still more than you should or would want to sanely burn in any wood stove that size. A max burn rate at 60k BTU/hr should come out to about 7.5 lbs wood/hr, and that's still cookin'.

Very interesting, thank you!

 

[Max W]

What is it about a 5x7 oval liner (35 sq inches) that won’t work with a 6 in (28 sq inches) draft stove?

 

[NorMi]

There's nothing wrong with it in general, but the area is most commonly about 24 square inches in flex liner that size. By scaling use of the stove to known UL maximum ratings, you ensure that you don't exceed the draft speed or volume per square inch of a given pipe, as long as the manufacturer ratings don't limit you further. Draft speed and flow rates are not constants on wood burners anyway, and the variance of flow characteristics allowed by most stove manufacturers based on draft pressures is usually larger than the variance between 5x7 and 6" pipe. Once you further account for the variances introduced between high and low burn rates on stoves, the pipe size example in this case is trivial. We just have a lower safe maximum continuous burn, and as UL standards are safety standards, already have a margin of safety accounted for and are not truly "maximum maximums" near a point of failure.

 

[bholler]

What is it about a 5x7 oval liner (35 sq inches) that won’t work with a 6 in (28 sq inches) draft stove?

It will work. Yes the volume is a bit higher but an oval won't flow quite as well as round so it will close to even out. It also depends upon the actual shape of that oval the volume may not be as high as 35