[Greenbuilding] firewood moisture content - a question for Norbert perhaps
frank at livingsol.com
Sat Dec 17 11:16:17 PST 2011
Just checking in on this discussion as well. This is great stuff, and
right to my heart.
I agree with Corwyn's comments, and can verify that if stuck with having
to burn wet wood, splitting it finer than usual, and burning it hot will
result in good heating and lower opportunities for creosote
accumulation. I consider wet wood as anything moister than 15%, (here
in a moderately moist climate zone). To achieve 15% or less, I dry the
wood, in full sun, in single or double rows at the most, under scrap
roofing steel, or other water-shedding materials for a two year period
before burning. This usually dries the wood to about 17% to 20%
moisture. In Autumn, before the rainy season, I bring the wood into my
wood shed for the reduction of it's last 5% of moisture.
As this may seem to create more work, I've had to really evaluate that.
What I've found is, that if you get your wood piles going, with two
years worth of wood, then you will have no problems if you're overtaken
by calamity, i/e., back injuries, sickness, broken bones, etc. What I
learned from the old-timers in our area is that getting ahead, two
year's worth, is like money in the bank. Over two year's passage of
time, the price of wood will go up. So right off the bat, you are
investing in your fairly-immediate future, and saving money.
The other advantages of very dry wood are that the house receives more
BTU's per cord of wood. This results in less wood to bring in, and fewer
ashes to take out. Also, there will be less wood burnt each year, thus
saving more money. As well, it is much easier to kindle dry wood, so
using dry wood makes life a lot easier. The stove controls are more
responsive, the cookstove oven comes up to temperature easier, and even
an older model stove handles like a good sports car.
Thank you, Norbert, for once again offering my friend and neighbour's
website link, at woodheat.org. John Gulland has had roving workshops
through out Central Ontario, including a "burn trailer", with two
different actively-firing woodstoves on the trailer, to see various burn
cycles, and the affects of different makes and designs of wood stoves.
His presentations are called "Burn It Smart". Even older,
stuck-in-their-ways woodburners, who already know Everything about
burning wood, come away with greater understanding, going home to split
their wood a bit finer, and burn their fires hotter, but for a shorter
length of time.
John Gulland is responsible, collaboratively with a few others, for the
excellent technical writing of Ontario's stove and instalation
requirements. His work, and the resulting codes, have saved countless
homes from burning down.
I also recommend his newer addition:
This is a discussion group, and there is enough questions and answers in
it, to fill a book, coming from all sorts of novice and experienced wood
Living Sol ~ Building and Design
613 756 3884
At 10:43 PM 17/12/2011, Norbert Senf wrote:
Interesting discussion, I haven't had a chance to check the list as
regularly these days.
Something really interesting that I only learned recently is that tar
(creosote) is only formed by smoldering combustion, which is without
flames. On the other hand, soot is only formed by flaming combustion.
You can have both types of combustion happening at the same time, in
different parts of the firebox.
Dry wood burns faster (hotter) and small wood burns faster (hotter). If
you restrict the air supply, wood will burn slower (cooler), and can go
from flaming to smoldering. Wood with 25% moisture can burn clean, if it
burns fast enough. You can burn cleanly with even an old-tech stove by
burning with the air supply wide open. The problem is with matching the
heat output of the stove to the requirement of the house.
A good way to tell is if your chimney stays clean, like Corwyn's.
Burning wet wood, he might still be able to keep it clean if he is able
to burn the wood hot enough by using smaller pieces, burning with the
air wide open, etc.
Nothing beats dry wood (20%), it just makes the job so much easier. You
pretty much need to have a woodshed, and get your wood in there a year
ahead of time.
Probably the best resource on the web on how to burn a stove is John
Gulland's woodheat.org website:
Best ...... Norbert
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