# Gasification Boiler Annual Wood Consumption



## altheating (Aug 15, 2010)

Since it is a bit slow in the forum how about a little survey.  Indoor gasser users only!  List how many full cords of firewood (4' x 4' x 8') you used last heating season (October 1st - April 30)  The square footage of your house, brand of boiler, storage or no storage.  If you used an traditional outdoor boiler in the past, what was your savings on firewood consumption using the gassifier?


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## chuck172 (Aug 15, 2010)

Just a thought with this survey. I have a Tarmsolo 40. It has a 5.35 cu. ft. firebox.
You're talking a 7 month heating season, thats say 210 days. Most people burn two loads/day  during the cold weather. If you're just burning one load a day. You're talking 9 cords of wood. 
How many people will say they  actually burn 5 cords a year or less?


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## stee6043 (Aug 15, 2010)

I burned 3.5 last year heating between October 31 and April 1. 3200 square feet, with storage.


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## stee6043 (Aug 15, 2010)

chuck172 said:
			
		

> Just a thought with this survey. I have a Tarmsolo 40. It has a 5.35 cu. ft. firebox.
> You're talking a 7 month heating season, thats say 210 days. Most people burn two loads/day  during the cold weather. If you're just burning one load a day. You're talking 9 cords of wood.
> How many people will say they  actually burn 5 cords a year or less?



You can't figure cord count by "number of loads per day".  My firebox is less than half the size of an EKO 80.  And I burn roughly 3 loads per day in the dead of winter...


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## chuck172 (Aug 15, 2010)

I can figure one load stacked in my boilers firebox is  5 cubic feet, and a cord of wood is 128 cu. feet.


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## wood thing (Aug 15, 2010)

A VERY GOOD QUESTION,  THIS HAS BEEN ON MY MIND FOR A WHILE.  MY NEW ECONOBURN HAS BEEN IN SERVICE SINCE MARCH OF 2010.  I HAVE 1000 GAL PRES STORAGE.  I HAVE CONCERNES ABOUT WOOD CONSUMSTION.  I HAVE BEEN BURNING ALL SUMMER AND IF I AM USING THIS AMOUNT OF WOOD NOW, I WONDER WHAT IT WILL BE LIKE IN WINTER.  I WONDER IF ANY BODY WEIGHES THEIR WOOD BEFORE LOADING ?  NOT WANTING TO POST A STUPID QUESTION, BUT THIS MAY PUT EVERYBODY ON AN EQUAL BASIS.  PLEASE CONMENT AND THANK YOU


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## tom in maine (Aug 15, 2010)

A little under a cord and a half for October to May. Heat and hot water.
The house is 1100 square feet. The basement is also heated, if that is included, it is 1600 square feet.

We used a prototype wood boiler. Will be using a new prototype this year and will hopefully use less wood.

Usual burn was about 3 hours a night.

346 gallons Heat Bank storage.


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## chuck172 (Aug 15, 2010)

When you figure a cord is approx. 25 full firebox  loads of wood. If you are burning 2 loads a day. Lookout, thats a cord of wood every 12 days or so!


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## kabbott (Aug 16, 2010)

chuck172 said:
			
		

> Just a thought with this survey. I have a Tarmsolo 40. It has a 5.35 cu. ft. firebox.
> You're talking a 7 month heating season, thats say 210 days. Most people burn two loads/day  during the cold weather. If you're just burning one load a day. You're talking 9 cords of wood.
> How many people will say they  actually burn 5 cords a year or less?



Interesting to see the  amount of wood some of you use. I was going to build a gasser but my work has picked up and will not have the time to devote to that project so 
I am thinking I will buy one.

I am not sure where chuck172 was headed with this comment but the most I have ever used in my homebuilt conventional boiler is between 7 and 8 full cord.
I am hoping to cut this almost in half. 2500 sq feet not counting basement, most very well insulated but some rooms have NO insulation.(a work in progress, built 1867) Added
siding w/foam insulation + house wrap this summer so that should help.

Sound doable???


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## solo40 (Aug 16, 2010)

Tarm solo 40, 4000sf, no storage.  10 cords or so.

Ethan


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## Piker (Aug 16, 2010)

wood thing said:
			
		

> A VERY GOOD QUESTION,  THIS HAS BEEN ON MY MIND FOR A WHILE.  MY NEW ECONOBURN HAS BEEN IN SERVICE SINCE MARCH OF 2010.  I HAVE 1000 GAL PRES STORAGE.  I HAVE CONCERNES ABOUT WOOD CONSUMSTION.  I HAVE BEEN BURNING ALL SUMMER AND IF I AM USING THIS AMOUNT OF WOOD NOW, I WONDER WHAT IT WILL BE LIKE IN WINTER.  I WONDER IF ANY BODY WEIGHES THEIR WOOD BEFORE LOADING ?  NOT WANTING TO POST A STUPID QUESTION, BUT THIS MAY PUT EVERYBODY ON AN EQUAL BASIS.  PLEASE CONMENT AND THANK YOU



This is important.  There is so much variance in the btu content of a cord of wood that to even talk about how many cords you burn is almost void of meaning.  I mean, we all do it, and for a round about number i guess it's at least something to talk about... but For example, a cord of Hickory contains almost twice the Btu content as a cord of poplar.  

The only real way to get an accurate comparison would be to measure weight AND moisture content... and even then, getting an accurate measurement on the moisture content is difficult.

Wood thing... A couple of notes on your wood usage concerns.  In my experience, folks tend to use quite a bit more BTU's for DHW than they realize... and the usage usually goes up once they start making hot water with a wood boiler.  (in our case, we tend to wash more clothes with hot water instead of cold, more baths in the giant soaking tub we have upstairs, etc etc.)  I have seen estimated average use for a family of 4 to be 70 or 80,000 btu's per day... with our standby loss from the tanks, we see about 160,000 to 170,000 per day, or roughly twice what the 'average' is.  Probably 35-45,000 of that is standby loss over a 24 hour period.  Don't underestimate your DHW demand... and remember to put that into perspective with your heating load...  For example, our 24 average for heat load is less than 35,000 Btu's per hour on our 4200 square foot home here in northwestern PA on a design temperature day (design at around 0° F)  so even on the coldest day... which only happens a couple times per season, DHW is almost 20% of the wood usage.   Actually a little less than that because during the winter the 35000 or 40000 btus per day that are "lost" from standby aren't really lost since the tanks are inside... so say 16%.  At any rate, what I am getting at is that DHW and standby losses during the summer can eat more btu's than you think, and are most likely out of proportion to what you think they should be with regard to your heat load.

I wouldn't fret until you get into the season and see what happens.

cheers


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## wood thing (Aug 16, 2010)

PIKER --- I COULDN'T AGREE MORE.  I HAVE KNOWN THIS FOR A LONG TIME, JUST YOU SAY IT BETTER !  THE HEATING SEASON IS GETTING CLOSER SO WE SHALL SEE.  THE NEW GASSER HAS TO BE BETTER THAN WHAT I WAS USING BUT I KNOW YOU UNDERSTAND THE FEELING.  BY THE WAY I LOOKED AT YOUR WEBSITE FROM ANOTHER POST --- VERY NICE.  STILL DON'T KNOW WHERE YOU ARE.   THANKS FOR THE REPLY.


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## jebatty (Aug 16, 2010)

All CAPS  are hard to read. Lower case is much easier on the eyes and brain. Many feel that CAPS are used for shouting, not talking. Advice given to be helpful, not critical.


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## Piker (Aug 16, 2010)

wood thing said:
			
		

> PIKER --- I COULDN'T AGREE MORE.  I HAVE KNOWN THIS FOR A LONG TIME, JUST YOU SAY IT BETTER !  THE HEATING SEASON IS GETTING CLOSER SO WE SHALL SEE.  THE NEW GASSER HAS TO BE BETTER THAN WHAT I WAS USING BUT I KNOW YOU UNDERSTAND THE FEELING.  BY THE WAY I LOOKED AT YOUR WEBSITE FROM ANOTHER POST --- VERY NICE.  STILL DON'T KNOW WHERE YOU ARE.   THANKS FOR THE REPLY.



Thanks for the nice comments on the website.  It's taken me a few years to put everything together, and to be honest, it's taken just as long to come to the understanding that I now have of wood heating and hydronic systems.  That having been said... the day you decide that you know enough is the day that you start to go backwards.  You can find our location on the Google map on the contact page.  Northwestern PA.

In my opinion the Econoburn 150 is probably the better unit in their lineup...   If you are comparing it to something that doesn't have a secondary burn of some sort, then yes, you will do much better on wood consumption.   1000 gallons of storage should really work nicely with that boiler assuming you have adequate delta t to work with and that you can keep standby and transmission losses to a minimum.  Just remember to keep the heat exchanger brushed out.  The mechanism that scrapes the turbulators up and down inside the heat exchanger only gets maybe 1/3 of the surface area inside the tubes because the stroke on the mechanism is shorter than the pitch on the turbulator twist.  With storage, your heat exchanger should stay clean from creosote, but will still get a nice coating of fly ash that will ultimately reduce thermal transfer quite a bit.  

cheers


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## EricV (Aug 16, 2010)

5-5.5 cord, sept 1 to end of august, Tarm solo 40, 1000 gallon home made tank, 1800sq ft, very high DHW draw.
less than 100 gallons oil


Grin when oil trucks passes my house, priceless!
Warm fuzzy feeling looking at my shed that will hold 40 face and it's 1/2 full already, also priceless


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## Nofossil (Aug 16, 2010)

I average a bit less that 4.5 full cords per year - 3500 square feet to 72°F , includes 550 gallon outdoor hot tub and DHW, October through April (more or less) each year. My wood is dry but a good deal less than ideal, and includes a lot of punky wood, poplar and red cedar. I expect that if I were burning straight hardwood I'd be comfortably below 4 cords per year. YMMV. There's a lot of difference in wood consumption based on burning style (continuous vs. intermittent fires).

As mentioned in my sig, it's an EKO 80 with storage. I'm in Vermont.


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## chuck172 (Aug 16, 2010)

I wish I knew the secret of 5 cords a year. That comes out to 125 full loads. Give or take. I burn nothing but seasoned oak and hickory, throw in just a portion of ash and red maple. All very well seasoned and dry.
This year to keep my wood total down to 6 cords, I think I'll supplement some oil and definitely burn my Lopi wood stove more often. When your used to a gassifier boiler, you realize a wood stove is nothing more than a space heater.


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## SolarAndWood (Aug 16, 2010)

Did any of you guys go from heating exclusively with a stove to exclusively with the gasser?  Everything else constant with the house,  wood, etc?  Those big houses must be super tight or there is a huge benefit to the boiler over a centrally located stove in an open floor plan.


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## Piker (Aug 16, 2010)

SolarAndWood said:
			
		

> Did any of you guys go from heating exclusively with a stove to exclusively with the gasser?  Everything else constant with the house,  wood, etc?  Those big houses must be super tight or there is a huge benefit to the boiler over a centrally located stove in an open floor plan.



Before I knew about gasification, we used a 30 year old Energy Mate forced air wood furnace in the  basement for about 10 years.  (came with the house) Average fuel consumption was between 8 and 10 cords to satisfy the entire season, depending on season and wood species etc. and also how much propane we decided to use  This setup worked well enough for us, but most of the upstairs did not get any heat from the wood furnace, and we used electric heaters in the bathroom and in the kids room.  No DHW.  With the first gasifier we owned, our wood usage without dhw was between 5.5 and 6 cords the first heating season.  The second season added thermal storage and DHW to the system along with some really nice firewood, and we still saw just shy of 6 cord.  I suspect with the froling we will drop closer to 5 cord... plus I plan on adding a good brazed plate to the DHW which will help us use lower tank temps to make dhw... and therefore increase efficiency of the system a bit.

Again... all these figures are completely dependent upon quality of fuel and the type of winter we have.  

One of the issues that people face with their wood burning equipment is the overheating of their living space.  Many of the less expensive wood stoves that you find at places like tractor supply have poor draft controls, resulting in 80° + temperatures in the house... basically if you are keeping the house warmer than it needs to be, your design differential (inside to outside air temps) are greater and will require more fuel.  A good centralized boiler system with zones keeps the heat in the system much better and prevents this overheating.  That having been said, I kind of like the 80° temps inside from a wood stove once in a while... we still have a fireplace that we burn in the living room for just such an occasion.

cheers


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## Bad Wolf (Aug 16, 2010)

This past year I "bought" 7 cords and was out by the end of march. I say bought because I don't think I ever get a full cord out of these people. 
I figure I've burned another cord over the summer for DHW. This is for a 3000sq ft two story colonial in New England, heat, DHW and 500 gallon hot tub. 
TARM Excel 2000 and 1200 gallons of storage, and I'm sure the wood was not as dry as it should be.  

As far as DHW goes I build a fire once every 4-5 days in the summer, thats for 4 people, and the hot tub. Which doen't come on much in July but does in April and October. At 1200 gallons thats 10,000 BTU per degree and I'll go from 155 to 125 over the course of the 4-5 days so I figure 75,000 BTU /day standby and usage. 

This year I'll have a true 8 cords stacked up and I won't touch it until Oct. 1st. and I'll be able to see how much I use between then and the end of April.  After that hopefully my solar panels will be able to supply DHW.


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## SolarAndWood (Aug 16, 2010)

Thanks Piker, that helps.  I assume that the decrease in your wood consumption when you went from the furnace to the boiler was a combination of combustion efficiency and distribution efficiency?  It seems that no boiler is going to compare to an efficient stove with good draft control in an open floorplan (my stove sits in an 1100 sq ft room that never overheats)?  i.e. I should be buying the smallest boiler to take care of the few remote rooms and dhw?


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## sootsucka (Aug 16, 2010)

Piker, was the energy-mate a boiler or warm air furnace. I have a energy-mate boiler and wondering on how much wood consumption would go down with a gasser. Did you switch anything else when you went from one to the other


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## MrEd (Aug 16, 2010)

I am going to keep better track this year, but I bet I used 8-9 cords last year. I am hoping to use less this year between adding a 500G tank for storage, and adding another R30 of insulation to the attic. Given that I was using 2000 gallons of oil before I went to wood(last year I used 100), it is not surprising the amount of wood I am going thru. Especially considering with oil I kept the house at 62 at night and 68 during the day, and now I keep the house as 68 at night at 73 during the day. SO I get a lot more heat for a lot less money (and I figure I paid back my investment in 2 years!)

BTW, that is in a cold part of New England, in a 2500sf house.


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## flyingcow (Aug 16, 2010)

Basically 6.5 to 7 cord year round. Rock maple/beech, still about 22/20%mc. 2 story,1800 sq/ft w/ 2 adults, 3 kids in teens. This includes DHW in summer. I stacked the wood very tight and piled it so each row was a 128 cu/ft cord. Usually used about 1000 gals of heating oil yr round. But we are keeping house warmer in the winter than we did with oil. I expect to burn a little less, once wood gets a little drier.  


Solo Innova-30  w/ 820 gals of storage


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## Piker (Aug 17, 2010)

SolarAndWood said:
			
		

> Thanks Piker, that helps.  I assume that the decrease in your wood consumption when you went from the furnace to the boiler was a combination of combustion efficiency and distribution efficiency?  It seems that no boiler is going to compare to an efficient stove with good draft control in an open floorplan (my stove sits in an 1100 sq ft room that never overheats)?  i.e. I should be buying the smallest boiler to take care of the few remote rooms and dhw?



Yes, I think you are correct with regard to combustion and distribution efficiency having a direct effect on our reduction of fuel usage and increase in overall comfort inside the home.  It's not like we just swapped out furnaces/boilers and ended up cutting our usage... the entire system was revamped from scratch.  With that in mind, it's still amazing that we were able to heat more of our home with significantly less wood.  

Regarding your thoughts on boilers vs. efficient wood stoves... I guess it all depends on what equipment you are comparing, and of course the respective systems you are hooking them too.  A good catalytic stove or even just an airtight stove in an open floor plan can definitely work pretty efficiently.  Since we picked up the Thermo-Control stoves and boilers in an attempt to satisfy another market niche, I have been privileged to talked to quite a few owners in the area and received some impressive feedback on wood usage for those products as well.  There's a lot of stuff out there... and to be honest, a lot of it is pretty good... definitely something for everyone. 

I think it's important to remember that folks who burn wood don't all do it for the same reason.  The gasification boilers tend to offer the highest efficiency under most applications, and also the most convenience when connected to thermal storage systems.  The simple fact that they are boilers allows them to be integrated into even the most sophisticated hydronic heating systems capable of heating large multi zone dwellings or even multiple structures.  The bottom line is, you get a whole lot more than just efficiency with one of these units.  The small, efficient wood stoves definitely have their place, and when budget is the main concern, these little guys tend to offer a petty fast return on investment.  

If you are considering adding a wood boiler to your current setup, I always recommend the smallest boiler you can stand to live with.  Smaller generally means shorter burn times, and increased efficiency.  If you're going with thermal storage, then oversizing is not really much of an issue providing you stay within reason of course.  There's a balance between boiler size and storage cycle times where a smaller boiler can actually give you longer firing cycles (obviously with reloading being required on any given cycle)  than a large boiler.  We try to keep the required burn time to less than 8 hours to fully charge the tanks on a design temperature day.  Any longer than that, and you end up not being able to get the tanks fully charged before bed.  

cheers


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## Piker (Aug 17, 2010)

sootsucka said:
			
		

> Piker, was the energy-mate a boiler or warm air furnace. I have a energy-mate boiler and wondering on how much wood consumption would go down with a gasser. Did you switch anything else when you went from one to the other



As noted above, the Energy Mate was a forced air wood furnace that was tied into the old ductwork in the house.  The system was by no means "proper," so it's only fair to say that part of our reduction in wood usage was due to the difference in delivery systems. I am not familiar with the Energy Mate boiler that you have, but it's probably fair to assume your usage would go down somewhere between 30 and 40% depending on what gasser you are looking at.  That's just an educated guess based on what i have seen in other similar situations.  

cheers


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## DenaliChuck (Aug 17, 2010)

2600 well insulated square foot house in Alaska

Radiant heat, and DHW for a family of four took 9.5 cord of white birch


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## mwk1000 (Aug 17, 2010)

I would say about 10 cords is what we use , we fill a 20x10 carport full to the top and that gets us through one season October-march. We have a 3500 sqft home with a 3500 sq ft basement ( 7000 ) total.

I used to burn a lopi "fireplace extrodinare" with the same amount of wood waking up every 3-4 hours to feed it. It made a small ( very small) dent in our propane bill. The EKO 60 with 1500 gal stopped our propane bill ( except for hot water). We used to have 68 in the day and 62 at night. We are 70 all the time now. ( Oh, and I don't feed it until 6pm-10pm ) That first year I sat in the shop staring at the thing not believing that it was heating the whole house.

I'm much happier that my effort in fetching , cutting, spitting now saves me money 3500-4500 per year in propane. The lopi can go back to doing what it was meant to do. " Look pretty once in a while" Nothing against the lopi, I love that furnace but it was never intended to heat the home, the insanely growing price of propane made that happen.

We are insulating to cut down the load, 2 years ago we added 2 feet more blown-in insulation to get me above R50 ( probably way above in some places )

This year we finish insulation over the basement walls ( started last year). I'm hoping that will save quite a bit 20% would be nice.


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## jebatty (Aug 17, 2010)

All the math on converting firebox size to cord usage doesn't add up for me. I almost never stuff my firebox full. And even if I did, with the rounds and splits, there is lots of air spaces between the wood pieces. Maybe I'll try an actual calculation, but I bet the average wood load is not much over 50% of firebox cubic capacity. And this works really well.

I have weighed wood in the past to get some reasonably accurate data on wood used to btuh output. I also can get a pretty good MC read on the wood, should be close to 20%. This year I will do the same and the data will be much better, as my boiler only feeds storage, I can shut down system draw from storage, and the storage is well insulated (R-30). Heat loss from the boiler on its way to storage will be quite minimal I have 8 sensors on the storage tank and can data log tank btu gain over time compared to wood burned. Will do soon, as temps are starting to fall in northern MN.


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## chuck172 (Aug 17, 2010)

The math works for me, and I almost always load my firebox full. My splits are fairly constant in size too. With only 500 gallons of storage, my tarm doesn't idle hardly at all. I do bring my tank up to aprox. 195*.
I try like heck to burn only one load per 24 hrs. When it gets real cold, I have to either burn two loads or use the Lopi woodstove too.


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## jashcroft (Aug 17, 2010)

Installed an Econoburn 150 last fall.  Burnt from Nov. thru March.  4000 sf well insulated house. Used 6.5 cords with no storage.  I think I can do alot better this year.  Learned alot last year about wood btu's, burn times, etc.


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## muncybob (Aug 17, 2010)

Apprx. 2000 sq ft, temps normally at 68 degrees in daytime, 70+ at night.  Used around 4.5 cords for heat and dhw, 2 person household.
This was our first year so we had the learning curve to get through along with being unprepared with good dry wood(another learning curve! )...I would guess that 1/3 of the wood we burned was in the 25 to 30% on the MM. We also use a programmable thermostat and the recent addition(900 sq ft) to our old farm house is kept at 66 unless it's being used.
Hope to do better this year if the winter temps are the same as I now have good seasoned wood. I don't think we really had any severe cold snaps that we normally get so I would consider last years temps a bit on the mild side and of course this makes a huge difference!


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