Fuel Wood Use Maths

I would never have thought, Johan! You keep surprising me :astonished:

Martin, it seems we suffer from the same illness. Unfortunately there’s no treatment.


I hope you are getting surprised in a good way… Or at least in an o.k. way




I do. I find myself way behind when it comes to keeping track on things.


Good early morning to all.
The other side of the wood fuel equations maths is needed usage.

It has been for us our once-a-winter, high-pressure-bubble cold-cold for the past four days. With three more to go:

Call it 22F/-5C. Now very, very low humidity drying air outside for us.
Good-good. I can actually slowly dry wood in these conditions.
One Cord measure row of my winter wood I left outside as just too bugs burrowed. Covered with an old black plastic poly cover. It wind blew off in a rain storm, one raining overnight. Then age embrittled, weighted down better; it winds flapped and tore some holes leaking too much of our 10 inches of later-October/early-November rains soaking the top rows of wood chunks.
This cold I find the Mitsubishi mini-split heat pump spends 50% of its time in idle defrosting its outside unit.
So we must use this now wetted wood for heating.
Bring in 36 hours worth of wood into the house. Set the heavier, wetter, splits to slowly dry out at what would be true-dry-wood, too-close to the wood stove.
Then even still half dried only put two splits at time onto an established bed of hot wood coals:

Poor, picture in the artificial lighting one hour before true outside sunrise. Taken to get all of “my-system” elements shown. That wood piece in the lower lefthand corner was fully absorbed heavy wet. Sinker-wood. It will not even float. TWO full days drying set close to just now finally match the only half wet stack set too-dry-wood close on the stove righthand side. The used up empty middle missing row had been the true dry wood row stack to make the good charcoal beds in stove. The mini-split inside unit shown at no-heating idle while outside unit defrosting in the pictures upper righthand corner.

Yeah yeah. All by human hands must monitor carefully for safety working-the-system.
You want fuel-up and walk-away systems then in my FIRM experiences you simply must have true dry wood fuels!!
For me wet wood using is a needs-musts Devil-driven skill I hard learned as a back-up skill. Burning system must be continuous, to not lose its internal gross heating wet wood capability.
True dry wood, I cycle batch burn heat. Using half the wood overall in comparison.

Wetish woods can be used. At nearly 2X the consumption use rates.
So you fellows using so much wood annually . . . .
Maybe some is uninsulated heating spaces. Maybe some is air leaking drafty spaces your are heating.
Mostly . . . I will bet money; is not using true dry woods.
Steve Unruh


Here you go.
Light enough now to picture:

The half remaining Cord-row’s south face will get sun warmed later.

The north face left exposed to let the sun warmed humidity out.
Now freed up stacking purlins had kept the used up row up off of the ground - shown stacked at the base.
The heavy pull chains draped over to prevent the now doubled over, old torn plastic from winds flapping.
The IC engine driven 42 tons-force hydraulic wood splitter under the new-this-year brown tarp.


Steve, that’s probably true for some of us (me).
But also, 100% wood-heating - no artificial supplement - and not only the living space, but a warm garage/shop and hot tap water included, all of it 24/7, will consume quite a lot of wood.
For a few weeks now we’ve had from 0 F to 15 F most days. Only a couple warmer days with thaw, but never below 70 indoors. Luxury? Maybe, but as long as you pay with your own sweat…


With all of this wet wood and clothing in the house next to the fireplace to dry, to add extra moisture into the house is not needed? So there is no need to add any water in a kettle on top of the stove to add extra moisture to your wood heated house. Correct?


Correct BobMac.
Using the sweeping out wood stove flue I can handle at least three gallons/18 pounds of moisture every 24 hours. Vaporized. Drawn in. Up, out, and away.

Shoulder months of April/May/early-June my wood stoving is mostly for dehumidifying the inside.

J.O. I 100% agree. Wood-sweating is a very practical energy usage check point.
Have as much and you can personally sweating support.
Buying out; “market-comparing” for your heating energy lends to all-you-can eat pigging-out, over-consuming.


Can you explain the sweeping out flue


When I am winter heating for needs I burn very, very hot with very slow allowed flue up flow. Burns clean and allow for the maximum to interior heat transfer.
Shoulders seasons - late Fall; especially in the wet, wet Spring I need much less internal heating so allow for more air-in and a much higher chimney flue flow out. To carry out the interior air humidity.
I still burn clean. Last brushed sweep cleaned a chimney . . . . oh, over 12 years ago.
I see any visible chimney smoking anytime and I am turning around and back into the house poker rearranging chunks. I do not want the progressive internal chimney coating building up.
Plus to me . . . visible smoke in a wood stove is unrealized wood energy being wasted.
The crows need to take care of themselves. They do not help with the wood harvesting sweating.


I use somewhere around 9-10 full cords depending on how cold of a year it is and I don’t heat a shop like J-O (well I do heat it but with its own woodstove but only when I need to be there and it is not calculated in the other wood) but we do have a well insulated house, a large house though which explains some of the firewood and as J-O said perhaps we also keep our houses a bit too warm which would explain the rest of the extra firewood.
My wood is probably not as dry as I would want it as it is only split and dried one season and ideally I would like to extend the firewood shed this coming summer to get ahead and have two years firewood in it to have it better seasoned and more dry.
This year I know that I am using wood with too high moisture and too low heating value, I used a woodpile that had been lying too long and the birches started to be a bit mushy.


Well, for a start I compare my usage with the past and that means gas and pellets. Very refined fuels that gives the perfect starting point if one is heating the correct way.

Our house is from 2007, compared to new houses it can do a lot better. Compared to our previous house it is very very well isolated. Our previous was from 1900-ish. We stripped it and put a truckload isolation in it. Still, our new house is twice as big, the first in the village to catch the wind here in the polder (our old was sheltered between a big house and a big farmhouse). Usage was in both houses around 3000 m3 gas/ year. Sometimes it is better to build new then try to upgrade the old.

This came from outside a week ago. Already ok. After one of your tips Mr Steve this is the next step.

Going from 16 to 12% without an effort. But still I got a feeling that the little Atmos was using a lot this season. Normally three burns are enough to fill the 2 m3/500 gallon boiler. So installed a Lamdacheck yesterday.

No servo yet but manual adjustment. It apears I lost the path somewhere, back on track now. Burns where always smokeless but efficiency lower. Boiler is full again in three burns. Let the season begin.

Next is playing with the heating in the house. Tried a few fans to lower the watertemperature, less loss on the way.

First impression is ok.


Measured, calculated “Efficiency” is a very tricky thing JoepK.
It was Dutch John who introduced me to the tag-name-lable of Efficiency-Manic.

Ha! Then I realized I had been one once too.
My very first car at 14 years old was a then 15 years old very, very worn out full-sized Ford large V-8 sedan, automatic transmission. $25. USD. Learning some; my second when I was 15 years old was an even older smaller Ford sedan inline 6 cylinder, manual transmission. $35 USD.
My third vehicle at 16 years old an even older Volvo PV444 I-4 m.t $500 USD. My fourth at 17 years old then even more “efficient” an MG1100 1098cc sedan. Ha! Ha! Those I could solo push start!
Then onto use even less gasoline small motorcycles. Then onto even more energy-use efficient: a custom built multisided bicycle. And transit buses. Stupid; efficiency; maniac’ing. Stupid; because no wanting children and a house/home gal was any longer interested in the bicycle-nut I’d become.

Back to wood for fuel the most labor efficient handling TomH has showed as handle it the very least in a thrown up jumble pile stack. Process only then with direct usage.
I did the too for three years due to health problems. Not so bad out here if the pile is made on already dried ground. (Best up onto stack wooden shipping pallets.) Then plastic tarp’ed covered just as drought-break occurs. AND you use cut plastic tarping to allow for a full 4-6 foot perimeter out rain/snow drain off run out apron all around. Keeps the back seepage from wetting from the ground up.

My evolved no-visble-smoke, ever; was not for efficiency JoepK.
First a dare-challenge to myself I could beat-exceed our new Washington States air pollution standard of only 20 minutes in every 2 hours visible smoke allowed, while refueling.
I beat that.
Then a 180 degree change from the old neighbor ethic to being able to see the neighbors household heath check by seeing smoke out their chimney.
Late 1990’s and on with the wood-burners vilifing education going on down to the primary schools school level I no longer wanted neighbors to easy-see me woodstoving at all.
Children here are now taught woodstovers are tree-killers, planet polluters. Selfish. Greedy. Stupid. BAD-people.
No exaggeration here. A reality I’ve had to change to live with. Even with extended GenZ family.
So absolute numbers efficiencies chasing pursuits will run you off of a cliff if you let it.
Always balance all, and be practical.


So true. Life is a balance act, every day.

Well, about the smoke my thoughts are, more smell. And I dont want to bother anyone around us. Woodburn will/ might be banned here in the future. Some people cant or wont keep the fire the good way.
And playing with chips and an automatic feed messed up the settings. The Atmos got a new door now, bether insulation but the stones might be ready for a change. Thinking of Ben P carburator but Lambdacheck is plug without pray. Installed in an afternoon and filling the boiler is like it used to be now. Good enough and maybe, or not, bether with a servo attached.

For efficiency high fruit and further cleaning of the exhaust gasses a condensing heat exchanger would be fun. But only after finishing all the other projects. :smiley: life is to short.


I have two excuses for still having a big stack of unprocessed wood. One is that I can’t really start gathering it until the middle of October because a lot of it has to be hauled out of areas filled with stinging nettle, raspberry canes and massive amounts of ferns. Too much of a fight to get through them. The other is that it mostly comes off hillsides and I have to cut the logs and hand throw or roll the rounds and branches down to where I can load them and that can often take two or even three bouts before they get to the truck. That’s a lot of effort and I’m now older than a calcified dog turd and about 4 hours a day is my energy limit whereas even back in my sixties I could still hit an eight hour lick. Not the man I used to be but firewood still keeps me in good enough shape to kick some lib-tard ass if they get in my face. However, I highly recommend not getting old. It pretty much sucks.


Steve for what its worth as far as supplementing with a heat pump I would say a harder fire in the evening and a light take the chill out one in the morning for the coldest time of the year and an evening only in the shoulder seasons. The heat pump should gain its best efficiency during the daytime. Here the heat pump is effective just about all year. It will put out a 2.5 to 1 efficiency gain down to -15 Celcius. You can go lower with it but it ends up being a near 1-1 ratio so you might as well crank the electric backup and cut down furnace run time. Any chance of junk wood showing up? I do kind of miss my woodstove but not the yearly hustle to find wood.
CHeers, DAvid Baillie


Great use advices DavidB.
The one side of house outside heat pump gets any available direct sunlight for ~4 hours; 11:00 AM to 03:00 PM. Even on a cold day this makes a big difference:

Low winter sun and exposures-angles make huge differences. The air temp out there sun exposed high point today is 47F/+8C:

The Wife is muttering about our cats using her gates entrances new bulbs planter boxes as their litter-boxes.
She’s also warning back to the one dog NOT to dig in her first pair of boxes put in place, she un-wisely used a bonemeal mix fill in them.

You guys do not worry about me.
I have lots of around and about piles and died downed/wind put down woods:

What I have tried to show is that really wet wood can be used IF YOU HAVE squirreled-away some very dried wood to quick-make the initial hot wood char bed:

It was wood gasification, so dependent on an established hot bed of char, that taught me this.

Squirreling-away means hiding the really dry wood from the household who’d easy-use, burn it all up! (My she-who-must-be-obeyed bent over in the previous picture!)
A full Cord measure of three rows; 8 foot wide x 4 foot high x 18 inch lengths cut of very dry fir wood hidden in the Penske truck behind the ~1/2 cord of woods jumble mess:

Once the the last of my buggy cotton wood cord row is used up the black plastic will be transferred over to the old deck dimensional lumber tear-off. Same-same. All covered black plastic to the south. The majority of our wind blowing North Pacific weather comes from the south; southwest.
When any sun does hit it, it dramatically heats. The north side propped open to let the humidity vapor out. Better even than daily tarps pulling back. And late afternoon, re-covering before evening air moisture dew-down. You WILL forget! And be going backwards for moistures reducing.

Again. I have no problems anymore with our wood fuels needs. Have an evolved, local, proven system. Up-ass. Get out of the easy chairs; and Work Your Systems.
Steve unruh


Last year I threw a scoop of bone meal in all the planting holes for the tomatoes and cucumbers. They all got pulled up for some critter to get at that bone meal. Not really damaged to much but a big PITA.


Same here. I burn about as much wood in the summer as l do in winter. We do all our cooking on a wood stove and the exess heat heats our hot water. All together l burn probably 4 cords a year. I had to much other stuff to do till now but next year l expect to optimize things and cut the firewood consumption in half. Solar heater for hot water in the summer and, if it works out, pirolisis gas installment in the stove.