Can Firewood ever get to dry?

[randyg]

To wet and problems with creosote, and loss of BTUs drying out in the stove. Wet and dry and wet and dry causes dry rot. Inability to control/restrict air flow through the firebox might cause very dry wood to burn up to fast. I get all that.

I've heard that if firewood gets to dry, you will lose BTUs. Is this true, or hog wash? Opinions?

Actually, my WIFE asked me the other day, and had to humbly tell her that I was not sure? She dosen't stump me all that often.

 

[blackdogon57]

There is no such thing as too dry for stove wood. The drier the wood the more usable BTU. The challenge is to be able to cut off enough air so that it does not burn up too fast.

 

[lopro]

http://www.woodheat.org/index.php?option=com_content&view=article&id=63&Itemid=73

 

[Hedgerow]

There is no such thing as too dry for stove wood. The drier the wood the more usable BTU. The challenge is to be able to cut off enough air so that it does not burn up too fast.

+1... It's all about moisture content. I've never seen wood too dry... Now bugs??? That's a whole other problem...:msp_wink:

 

[Hedgerow]

http://www.woodheat.org/index.php?option=com_content&view=article&id=63&Itemid=73

Oh, and I'm thinking there's more to this fellow's opinion than meets the eye... Too much smoke from too dry wood??? Not sure of the science behind it, but this lamen doesn't see this in the real world of wood stoves...:msp_blink:

 

[Highbeam]

I don't trust anything from that woodheat site. Major flaws there.

So the wood in your walls of your home are in excellent burning shape. Even 100 year old homes have solid wood that will burn great. Your firewood will last if you can store it properly and not let it get wet.

The wood won't keep drying to 0% moisture content. There is an equilibrium there before zero.

I am not always able to store dry wood inside a dry barn, instead it is under plastic with the sides exposed. That means that at some point it gets too old. I decided to sell 4 cords last year before it was too late. Nice bonus is that you can buy cool stuff with the money from 4 cords of dry wood.

 

[blackdogon57]

http://www.woodheat.org/index.php?option=com_content&view=article&id=63&Itemid=73

Just because the guy posted an article on a website doesn't mean he knows what he is talking about. The part about dry wood producing more smoke is absolute hog wash. Lots of good info on woodheat.org - also lots opinionated garbage.

 

[laynes69]

In normal conditions its almost impossible to have wood too dry. I think if it hits below a certain percentage, it can off gas quicker than it can burn creating a rich environment. The same reason an engine will smoke when it's choked, a diesel that pushing more fuel, etc. If there is enough oxygen and the rate of fire is controlled then it shouldn't be a problem. Otherwise uncombusted particles are sent up the flue.

 

[Uncle John]

Can a woman be too pretty?
Can a car ride too good?

 

[goof008]

I could see it maybe if you were living in the desert where there is no relative humidity. because there is always (at least around here) moisture in the air, I think you will always have moisture in your wood.
That is given it is covered and stacked. I've burned punky wood in bon fires and it goes right up, never noticed an increase in smoke, but definitely a quick burn with little heat...and I've burned 30 year old 2x4's along with freshly bought and cut 2x4's...seemed to burn about the same.

If you have wood you are concerned with, drop it over and I'll try out a cord or two...just to make sure!!

can't have wood to dry, a car too fast or a chainsaw that runs too good! IMHO

 

[pook]

In normal conditions its almost impossible to have wood too dry. I think if it hits below a certain percentage, it can off gas quicker than it can burn creating a rich environment. The same reason an engine will smoke when it's choked, a diesel that pushing more fuel, etc. If there is enough oxygen and the rate of fire is controlled then it shouldn't be a problem. Otherwise uncombusted particles are sent up the flue.

bingo+ excess uncombusted CO an invvisible fuel
c>co>co2 equates to [per energy units]
3.5>1>2.5 major loss in uncombusted CO

 

[CrappieKeith]

Wood that is @20% moisture can make 8000 btu'sper lb.
Wood that is @0% moisture can make 12,000 btu's per lb.

The problem with burn 0% moisture wood is that it makes to much heat too fast if uncontrolled and can over heat fireboxes in many furnaces and stoves and it is really tough to exchange those heats as fast as they are made.
You can make all of the heat in the world and if you can't exchange it the heats will still go out the flue pipe.
So if efficiency is the goal ...there is this balancing act....make the btu's then exchange them....making the btu's is where many wood burners fail....then again exchanging them many fail...hence the teeter totter balancing act.

 

[Slick]

I think the woodheat article summed up what I've seen before also, in my OWB at least. I had some old really dry wood last year, it burned way to hot and I didn't get to much heat to my water/house from it. I should have mixed it in with other wood, just a load of this stuff was an inferno that went up my stack...if I could have regulated the input air I guess it would have worked but that wasn't an option for me...so to me, yes wood can be to dry. I don't care how "well it's burning" if I can't GET the heat from it and it's going up my stack, it's not good firewood.

 

[CrappieKeith]

I had some old really dry wood last year, it burned way to hot and I didn't get to much heat to my water/house from it.QUOTE]

That is the point I was making...so how many wood burners are out there that are designed to burn kiln dried wood? None that I know of....and all of the testing we do in the States also call for cordwood not kiln dried.
15/20% seems to be the target number that we should strive for.

 

[randyg]

There is no such thing as too dry for stove wood. The drier the wood the more usable BTU. The challenge is to be able to cut off enough air so that it does not burn up too fast.

Many good replys, I like this first one the best. I quess that the best answer might be, depends on what you are burning it in?

Thanks for all the great info!
randy

 

[johnha]

There is no such thing as too dry for stove wood.

I disagree. There is a difference between seasoned and dried. I've had red oak that burns up like kiln dried pine because it was too dry.

Dry wood is good for kindling. Seasoned wood is good for heating.

 

[Hedgerow]

Something that has not been discussed in this thread is the fact that if you know your wood is to be super dried.......... larger rounds can be burnt. Larger rounds release their pyrolytic gasses slower than small splits do. By larger rounds I'm including larger splits also.

Some of my wood gets seasoned two years and in my Jotul Firelight on a good bed of coals (2 inch layer) I can roll a super dry round of oak in that fits by less than an inch.....(must open both front doors) ....and it will almost instantly go into secondary combustion mode and stay there for 5 or 6 hours...and melt down into a large bed of coals.

I can do the same thing with super dry pine but it burns faster and leaves less coals.

There is zero problem with over firing the stove!

In fact....if you want max output....don't try to get it with the largest round you can fit in your stove...because it won't give you max output.

Super dry large wood burns great!

Agreed...

 

[pook]

the stochiometric burn of pyrolyzed wood involves ~ 8 parts air to 1 part woodgas. Change that ratio & consequential results ensue

 

[Hedgerow]

the stochiometric burn of pyrolyzed wood involves ~ 8 parts air to 1 part woodgas. Change that ratio & consequential results ensue

Stochiometric, meaning "theoretical" burn. Is this ~ 8 to 1 by volume? Or weight? Just seems like 8 cubic feet of air isn't enough to completely burn 1 cubic foot of wood... Maybe it could in the lab. Of course my house is far from being a lab...:msp_sneaky:

 

[pook]

Stochiometric, meaning "theoretical" burn. Is this ~ 8 to 1 by volume? Or weight? Just seems like 8 cubic feet of air isn't enough to completely burn 1 cubic foot of wood... Maybe it could in the lab. Of course my house is far from being a lab...:msp_sneaky:

8/1 air to WOODGAS which boils off the wood @~500*f & if not properly burned results in creosote up the chimni,& or excessive unburnt CO fuel
basics= water boils @ 212*f, wood gasifies~@500*f, flame appears ~@1200*f, Simplified