$ per BTU: oil vs wood

[Kwill]

I don't see how the math works anyway. To many varables in wood. Different wood species burn different and last different.

[rank]

I for one find this topic quite interesting.

Most sources I've found say a cord of hardwood like ash, oak, maple, hickory from 24 million BTU up to 28 million BTU.  If we take these numbers as gospel, I am flabbergasted to discover that these OWB's are so inefficient.  I was thinking about getting one to heat my 80x100 shop but not so sure anymore.

I have a neighbor with a indoor hardwood boiler.  I know he only burns the best wood because he takes it from my farm and he leaves the softwood for me.  He says it takes 7 cords a year to heat his house and shop....that's ~175,000,000 BTU or equivalent to approx 1250 US gallons of oil......approx $5,000 CDN for the winter.....that sounds about right to me looking at the sq footage he's heating.  Another fellow I sell firewood to says oil costs him $1,000/month.  He says he's saving money burning my 50/50 mixed firewood his open fireplace!

One more question for Dave: How far is your OWB from your house?

[rank]

......and another question for those that are quoting hardwood prices in the $200 - $250 range.  Is this split and seasoned or in logs?

[Kwill]

200- 250 range around here that split stacked and your car washed for a year

[Dave Shepard]

Those prices are split delivered and seasoned. The boiler is 40' of Central Boiler 1" Pex, the insulated stuff,  to the heat exchanger,  then 80 feet through the basement to the oil burner.

[Kwill]

And that's for top of the line wood. Not hickory ash or any of that junk wood

[JJ]

My experience with dual heating sources is closer to Dave's:

The real deal is that the house uses 300 gallons a month or four cords of wood.

My indoor oil boiler used 700gal for heating season, while I burned 7cord of seasoned hardwood once I installed e-Classic as alternative.
Made math real easy.  If hardwood delivered is $235/cord (price i paid in my area); then if oil was less than $2.35/gal it was cheaper and easier to burn oil. [1 cord = 100 gal; for my situation].

I have new house now and wood heat is not an option (currently).   Each home and heating unit will have differences, this is just how it worked out for me.

         JJ

[Crusarius]

so here is a question that I did not see talked about. Are you guys that are getting what to me looks like very poor economy running forced air furnaces?

I have a switzer dual fuel boiler. It holds 700 gallons of water and is pumped through my concrete slab in the house. I have a 1000 gallon fuel oil tank which feeds the fuel oil boiler. I can run 2 winters using that as my primary heat source and burn roughly 600 gallons. The other fuel option for that boiler is wood. I rarely use that because I am lazy. The fuel oil is automatic I have to do all the wood.

I do have a wood stove in the house that is used to take the chill out of the air since the upstairs is not heated at all.

So are you guys all running forced air heat?

[Dave Shepard]

 I'm tied into my oil boiler. Cast iron baseboard and radiators.

[Crusarius]

how big of a reservoir? or is there any? its amazing how long 700 gallons of water stays warm. That is probably why mine is so efficient.

[Dave Shepard]

400 gallons on the wood side of the exchanger.

[JJ]

No, Baseboard hot water with radiant heat in slab for 1/2 of the lower floors.
My home had several additions, with quite different r-ratings for each build.  Older walls were 2x4, newer walls 2x6 with higher grade insulation.
Sounds like your house is considerably better built (tighter), or smaller (I had 3500 sq ft to heat), and a has a very efficient heating system.
In Maine, I was not that much further north than Canadice, so climate should have been similar.

Each home and heat system will have differences, so going by pure BTUs will not give the answer if it is saving money to heat by wood, or oil.   I think end result is what matters most.

         JJ

[rank]

And that's for top of the line wood. Not hickory ash or any of that junk wood

What's wrong with hickory?

[rank]

Each home and heat system will have differences, so going by pure BTUs will not give the answer if it is saving money to heat by wood, or oil.   I think end result is what matters most.

For someone trying to decide on installing a wood burning appliance, The home is a constant in the equation So I guess I'm thinking if it takes x btus of oil at a certain efficiency it should take the same btus of wood at a certain efficiency. 

installing a boiler just to find the answer seems expensive

[Kwill]

And that's for top of the line wood. Not hickory ash or any of that junk wood

What's wrong with hickory?

burns up to fast

[Al_Smith]

It must not be the hickory we have in the north . Our stuff has slightly more btu's per cord as ton of hard coal .--Google it ,shag bark hickory .Try ash too it isn't far behind oak .
You want a hot fast fire stoke it with little pieces .Longer lasting fire  larger pieces ,simple . ;)

[Al_Smith]

Now here is good ole Dave in Mass .Big old drafty house,cord a week .Then comes old Al in the middle of a corn field who burns  a little over a cord a month in the coldest of weather .--Now  this is 2200 sq feet on one level,brick with thermopane  windows and insulated like it were in Alaska .There in lies the difference .

[Kwill]

I think I will stick with the red oak. I mix in some hickory occasionally. I actually got several I need to cut down. May burn some next season as I will let it season from now till then.

[Al_Smith]

Yes indeed red oak is good firewood with one drawback .It doesn't weather well .Unlike white oak that does .I burned up several  cords of red  in my slash pile  last summer that had laid  on the ground too long before I got to them .< long story .The white oak,same length of time in ground contact,solid as a rock .That said you have to burn whatever you have .--it all produces heat . 8)

[Dave Shepard]

No, my owb isn't the greatest choice, but it is what I have. I have $2500 and three days of letting my plumbers dog out while he was on vacation invested in  it.  :D I only burn sawmill byproducts and hazard trees removed by my town. No trees have been taken down solely for the purpose of heating my house.

If one was building a new house, I would suggest putting every available penny into insulation and high R windows. Netzero would be my goal at a minimum.

$15,000 for a gasifier installed with Pex and a heat exchanger.
$15,000 for a hydronic primary system to tie into.
$40,000 for 25 years worth of wood @ 8 cords per year (Remember, you spent all your money on an owb, you couldn't afford the good windows or extra insulation, and let's assume the boiler actually survives the 25 year warranty :D).
$ for your time to feed the boiler, and clean up the mess.

That's $70,000 That could be spent on net metered solar, high R insulation, good windows, and a little electric heat for the days that the planned for solar gain isn't available.

Sure, my numbers are generalizations, but it is food for thought. At the end of either plan is the replacement of the boiler or pv system. In 25 years boilers will probably be illegal and a new pv system will probably just roll out as the new roof you needed anyway for a fraction of what either a roof or pv system cost in the beginning.

[rank]

... I only burn sawmill byproducts and hazard trees removed by my town.

Is the bark still on these slabs?

[Dave Shepard]

Usually, but not always.

[Kwill]

Yes indeed red oak is good firewood with one drawback .It doesn't weather well .Unlike white oak that does .I burned up several  cords of red  in my slash pile  last summer that had laid  on the ground too long before I got to them .< long story .The white oak,same length of time in ground contact,solid as a rock .That said you have to burn whatever you have .--it all produces heat . 8)

I will have to disagree with you on red oak not weathering good. We had the place logged the end of 2012 first of 2013. Had red oak and post oak logged. The tops from the red oak stayed in good shape unlike the post oak. They got soft within the first year. Some of the red oak was 3 years before I got to it and it was all still in good shape and solid.

[rank]

Usually, but not always.

that certainly answers some questions for me about missing btu's

[Dave Shepard]

I'm not using slabwood when I'm talking about dry hardwood, I'm talking about cut, split and seasoned ash, hard maple, cherry, and red oak. Most of my slabs are pine. It takes almost two cords of slabs a week when its really cold.

Couple days wood when it's near zero. No ash from the softwood, which is nice.