# Wood to Ash Conversion Ratio



## firecracker_77 (Oct 14, 2012)

As I'm cleaning out the stove and dumping my 5 gallon ash can, I was trying to calculate how many pounds of wood it takes to fill an ash can.  I have no clue.  I would guess for every pound of wood you burn, you end up with only a few percentage of that initial weight in the ash...

If you burn about 4 cords a year of better hardwood, that's somewhere between 3,000 and 4,000 pounds of wood per cord or 12,000 to 16,000 pounds total.  Using 1% as a rule of thumb, that would be about 120 to 160 pounds of ash to clean-up. 

This isn't a woodstove.  It's a wood crematorium.  Anyone ever try and figure this out when cleaning up every couple of fires?


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## aussiedog3 (Oct 14, 2012)

I would guess 1/2% or less.  I let my stove build up a little bit of ash layer in the bottom as insulation for coals.  I think it just continues to break down more and more and when I do clean it out, somethimes it comes out like a cake.  It has some volume but not much weight.  I burn 24/7 from November thru March and I doubt I shovel out four 5 gallon buckets full total and I know they are very light.
I'd like to know what others think.


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## firecracker_77 (Oct 14, 2012)

aussiedog3 said:


> I would guess 1/2% or less. I let my stove build up a little bit of ash layer in the bottom as insulation for coals. I think it just continues to break down more and more and when I do clean it out, somethimes it comes out like a cake. It has some volume but not much weight. I burn 24/7 from November thru March and I doubt I shovel out four 5 gallon buckets full total and I know they are very light.
> I'd like to know what others think.


 
During this shoulder season, I haven't been going 24/7 and am cleaning out almost every day.  There is a little more weight as I'm scooping out some unburnt wood..very small pieces


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## CageMaster (Oct 15, 2012)

november to march 24/7 and all my ash goes into a barrel, in the spring we go and dump the barrel, last year i burned 6 cords and the barrel was 2/3 full, so thats 35 gallons of ash.


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## firecracker_77 (Oct 15, 2012)

CageMaster said:


> november to march 24/7 and all my ash goes into a barrel, in the spring we go and dump the barrel, last year i burned 6 cords and the barrel was 2/3 full, so thats 35 gallons of ash.


 
that's interesting to note.  6 cords yields about 2/3 of a 55 gallon drum or about 36 gallons of ash


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## CageMaster (Oct 15, 2012)

firecracker_77 said:


> that's interesting to note. 6 cords yields about 2/3 of a 55 gallon drum or about 36 gallons of ash


 
keeping in mind that is a mix of hardwood and softwood, probably about 1 cord was oak, 3 cords a mix of maple and 2 cords of poplar.


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## firecracker_77 (Oct 15, 2012)

CageMaster said:


> keeping in mind that is a mix of hardwood and softwood, probably about 1 cord was oak, 3 cords a mix of maple and 2 cords of poplar.


 
that ash weighed less than 100 pounds then and you burned somewhere around 20,000 pounds of wood?  that would be 1/2 of 1% remaining out of all that wood by weight.


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## CageMaster (Oct 15, 2012)

I would believe that to be correct...the NC30 is very effecient


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## Standingdead (Oct 15, 2012)

aussiedog3 said:


> I would guess 1/2% or less.  I let my stove build up a little bit of ash layer in the bottom as insulation for coals.  I think it just continues to break down more and more and when I do clean it out, somethimes it comes out like a cake.  It has some volume but not much weight.  I burn 24/7 from November thru March and I doubt I shovel out four 5 gallon buckets full total and I know they are very light.
> I'd like to know what others think.



I use my wood stove shoulder season ash to act as a starter ash bed in my boiler once I fire up the beast in early November. Maybe it's my imagination but a couple inch ash bed seems to allow the boiler to run better. I guess I produce around 100 gallons of ash burning 8-9 cords of wood. I spread the ash on my stone dust driveway once it ices up.


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## RORY12553 (Oct 15, 2012)

firecracker_77 said:


> During this shoulder season, I haven't been going 24/7 and am cleaning out almost every day. There is a little more weight as I'm scooping out some unburnt wood..very small pieces


 
I have the same stove and this is my 2nd year burning. I have been leaving the ash & unburnt pieces of wood in the stove. I find the cleaner the bottom the longer it takes to get things going. Leave the unburnt stuff in the stove all it will do is burn and create heat and will help cut down on the amount you are taking out of the stove. Like another person said it creates a covering for the coals to keep them warm.


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## firecracker_77 (Oct 15, 2012)

Standingdead said:


> I use my wood stove shoulder season ash to act as a starter ash bed in my boiler once I fire up the beast in early November. Maybe it's my imagination but a couple inch ash bed seems to allow the boiler to run better. I guess I produce around 100 gallons of ash burning 8-9 cords of wood. I spread the ash on my stone dust driveway once it ices up.


 
How big is the space you are heating.  That's 30,000 + pounds of firewood annually.


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## firecracker_77 (Oct 15, 2012)

RORY12553 said:


> I have the same stove and this is my 2nd year burning. I have been leaving the ash & unburnt pieces of wood in the stove. I find the cleaner the bottom the longer it takes to get things going. Leave the unburnt stuff in the stove all it will do is burn and create heat and will help cut down on the amount you are taking out of the stove. Like another person said it creates a covering for the coals to keep them warm.


 
When I'm burning 24/7, she does not get cleaned frequently, but this time of year, I have been enjoying a nice clean stove to start things off with.  I'm usually looking a for a little supplemental heat.  Usually a fire no more than 6 or 7 hours a day.


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## TMonter (Oct 15, 2012)

CageMaster said:


> keeping in mind that is a mix of hardwood and softwood, probably about 1 cord was oak, 3 cords a mix of maple and 2 cords of poplar.


 
Those are all hardwoods actually  at least in a technical sense. Really when you boil it down the term "hardwood" and "softwood" is really meaningless. With few exceptions though all wood has a ash content of around .5 to 1.5% by weight dependent on the species and how it was grown.


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## firecracker_77 (Oct 15, 2012)

TMonter said:


> Those are all hardwoods actually  at least in a technical sense. Really when you boil it down the term "hardwood" and "softwood" is really meaningless. With few exceptions though all wood has a ash content of around .5 to 1.5% dependent on the species and how it was grown.


 
That all makes sense to me.


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## woodchip (Oct 15, 2012)

I reckon my ratio changes depending on the season, proportinally more now than midwinter.
During the shoulder (now), I tend to start fires daily and use quite a lot of bark when starting fires, as well as a lot of smaller bits of wood.
Come midwinter, I burn 24/7, and only burn my best woods, which are split from bigger rounds which tend not to have much bark on them.


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## ScotO (Oct 15, 2012)

I know that some wood puts out a lot more ash than others.  I've cleaned my stove twice in the past several weeks, burning nothing but ash and soft maple (with an evening split or two of locust and white oak), but I'm not even burning 24/7 yet.  Fast forward to the dead of winter when I'm burning big loads of locust and white/red oak, and I don't have to clean my stove but once every two weeks.  So I think some woods (especially the softer woods) will put out a lot more ash than the denser hardwoods (oak, hard maple, locust, etc).


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## Standingdead (Oct 15, 2012)

firecracker_77 said:


> How big is the space you are heating.  That's 30,000 + pounds of firewood annually.



3500 ft plus DHW, plus occasionally large attached garage to thaw equipment when needed. Use more in a cold winter.


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## Flatbedford (Oct 15, 2012)

I have always been amazed that nearly 4 cords of wood ends up being about 60 gallons of ash. I clean out the Fireview every couple of weeks when we are into 24/7 burning...and that's only 2 gallons or so.


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## TMonter (Oct 15, 2012)

firecracker_77 said:


> that ash weighed less than 100 pounds then and you burned somewhere around 20,000 pounds of wood? that would be 1/2 of 1% remaining out of all that wood by weight.


 
Which would not be abnormal for very clean wood. Clean heartwood pulp chips have about 1/2% ash by weight.


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## firecracker_77 (Oct 16, 2012)

That's all real intersting to me.  I never took the time to figure it out, but now I know.  I would clean the stove and then think about all the pounds I ran through there but not quantify it.


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