# How to compare coal to hardwood in outdoor woodburner??



## OJ Rallye (Aug 4, 2005)

Is there a way to compare coal to wood? I found BTUs per pound for coal but have no idea how to compare that to wood.


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## TnAndy (Sep 15, 2005)

You'll find various statistics if you do a search, but the one I see most often is around 7,000-8,000 BTU per pound. 

But since wood is generally bought on volume rather than weight, you'd need to know the BTU per cord, which varies considerably given some wood is far more dense than other.

Here is a chart that reflects that:

http://forestry.usu.edu/htm/forest-products/wood-heating


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## OJ Rallye (Aug 4, 2005)

Thanks Andy

That site (Which is good) lead me to this:

http://www.cce.cornell.edu/Environment/Documents/PDFs/Heating with Wood and Coal.pdf

I've been using woodheat.org a lot since we got the Heatmor several years ago.


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## kasilofhome (Feb 10, 2005)

There are different types of coal and there is a difference center in btus.


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## TnAndy (Sep 15, 2005)

Yep....coal goes thru several stages, each decreasing the moisture, and increasing the energy content.

It starts a peat, then lignite, then 'hard' coal ( what most people recognize as coal).....peat and lignite have more brown organic looking matter in them. 

Hard coal, is either bituminous (sometimes call 'soft coal') or anthracite, the later being the hardest, blackest, best form of coal to burn.

Which one you can get sorta depends on your area.


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## MichaelK! (Oct 22, 2010)

Well, I suppose the best way to answer this to to determine it yourself.

You can take a weighed measure of wood or coal (say a pound) and measure how high that amount when burnt, raises the temperature of a measured about of water, say one gallon.

I believe a BTU is the amount of heat that will raise the temperature of a pint (1 pound) of water 1 degree F.

So, if your gallon of water increased 100 degrees in temperature, your real-time BTU's would be 100X8=800BTU

Is there a real-world reason you are asking this question, such as you are chosing between buying a ton of coal or a cord of wood for next winter? There are parlor stoves (cookstoves too) designed to burn either wood or coal, with a change in a rotating bottom grate. Coal needs bottom air to burn properly.


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