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Highest heat output and BTUs

Post in 'The Wood Shed' started by gyrfalcon, Nov 23, 2008.

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  1. gyrfalcon

    gyrfalcon Minister of Fire

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    Given ideal draft, seasoning, split size, stove operation, etc., is there any real difference in the stove temps you can achieve between hardwood species? If so, is the difference reflected in BTU ratings, or does high-BTU wood primarily just make just a longer-lasting fire?

    I have an undersized stove out of which I need to coax the best heat possible, and I'm wondering whether it would be worth the effort to try to find a supplier who would agree to sell me just the high BTU species plentiful around here (mainly shagbark hickory and black birch) or whether the more usual mix of rock maple, soft maple, beech, etc., that I'm using now is giving me the best I'm going to realistically get.

    My stove cruises easily at 400, but I can't get it to 450 but once in a while for a fairly short period (like opening the primary air on a big bed of red-hot coals), and I've never managed to get it above that, despite using 4-inch splits and smaller. A consistent 400 keeps me from freezing to death right now, but I think I'm going to be mightly chilly when serious winter temps come in if I can't get the stove above that for more than the very occasional brief burst of enthusiasm.

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  2. Shipper50

    Shipper50 Minister of Fire

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    I am burning white oak for the first time in my burning life and find there is a major difference in the heat it puts out compared to black cherry. I bought some of each from a local farmer and they are both seasoned the same. My house is warmer with the white oak and less coals with it compared to black cherry.

    If your trying to get the most heat for your money, I would suggest trying other hard woods and find out which works the best for you.

    Shipper
  3. btj1031

    btj1031 New Member

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    I'm burning mostly oak right now, compared to mostly beech last year, and I'm getting longer burn times, not necessarily higher peak temps. Still have no problem getting to a cruising 650-700 with the right mix of splits. Also, I'm getting much more coal buildup, so much so that its often above the front lip of the stove, increasing the risk of coals hopping out when I reload. I guess there is a downside to burning oak, but I'm into it nonetheless.
  4. LLigetfa

    LLigetfa Minister of Fire

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    I see both a hotter burn and a longer burn time with some species given the same stove and same settings.
  5. Todd

    Todd Minister of Fire

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    The Rock Maple and Beech are not to far off the Hickory and Black Birch. I can tell the difference heat wise between a full load of Black Locust verses a full load of Silver Maple or Pine. My stove will want to peak over 600 verses 500. But as far as telling the difference between Locust, oak or hard Maple I can't really tell much diff.

    I question your wood moisture level. Most firewood suppliers don't sell dry wood. Try and get 1 or 2 years ahead if you have the room. Dry wood makes all the difference.
  6. gyrfalcon

    gyrfalcon Minister of Fire

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    Wood is quite dry, although not super bone-dry. I learned my lesson last winter about not expecting "seasoned" wood to be seasoned, so bought green this spring, well split down. It's been sitting in long widely separated stacks in full sun and nearly constant breeze since the end of April. Only the bigger pieces read as high as 30 on the moisture meter on the inside, and the rest of it is 20 to 25.

    In a year of reading posts on this site, I don't see small to medium soapstone stove owners getting above 500 very often, and usually down in that 400-450 range. (A "full load" in a 1.2 cf firebox is 4 4-5-inch splits and a few scraps tucked in here and there.) Seems to be the nature of the beast. But just eking that extra 50 out of the stove makes a pretty big difference when I can do it, so I'm trying to figure small things now that might get me there a little more often. Good to know the wood species available to me don't make that much of a difference-- but disappointing! I'm clearly under-stoved, but not sure when or if I'll be able to afford a larger one.

    Thanks for the input.
  7. gyrfalcon

    gyrfalcon Minister of Fire

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    The trade-off with soapstone is it doesn't get as hot as cast, but stores the heat and radiates it out much longer. I'm not sure whether that's the right trade-off for my situation, though, so the Castine is a stove that's high on my list to consider when I get to the point that I can afford a larger stove.

    We don't seem to have much oak around here, unfortunately. I'd love to try some, coaling and all. It may be in the forests, but it's not in the neighbors' woodlots, which is where I get my firewood.
  8. gyrfalcon

    gyrfalcon Minister of Fire

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    I've been experimenting with separating out the kinds I've got and burning one at a time with the same routine, and so far not finding a difference between soft maple, rock maple, blue beech, even my beloved black birch just this evening (beloved because it dries fast and lights fast), and some mystery wood I can't identify at all. I'd love to get my paws on some white oak, but it doesn't seem to be available around here at all.
  9. gyrfalcon

    gyrfalcon Minister of Fire

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    OK, but which species?
  10. LLigetfa

    LLigetfa Minister of Fire

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    Species of hardwoods in my area that I burn from best to worst:
    Birch - long drying time, bark is a PITA, stinks like cat piss
    Elm - stringy wood, hard to split
    Ash - short drying time, easy to split, nice smell (my fav)
    Poplar - easy to split, OK smell
    Bam - has too much water/sap, core rot
  11. Todd

    Todd Minister of Fire

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    Less than 25% is ok 15-20% is ideal. Your right that is a small stove. You probably won't get much more heat out of it. Maybe put an add out there to sell or see if a dealer would trade for a larger Hearthstone?
  12. gyrfalcon

    gyrfalcon Minister of Fire

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    Yeah, I'm not at ideal, and given the sheer physical effort of getting even a couple cords stacked in the spring and brought down to the woodshed in the fall, I'm not optimistic about the prospect of ever being able to get any further ahead and therefore to super-dry wood. (Single female household here ,nearing, ugh, the big 60, so it's all downhill from here.)

    I bought the stove gladly from neighbors when they moved a couple of years ago, not expecting more of it than to provide some comfort and joy of an evening. Like many, the astronomical rise in the price of oil up to this spring caused me to think about substituting wood heat for oil, with a stove not suited to do that. and now I'm an addict. I can surely sell it, but for no more than a dent in the price of a new and bigger one. Since it's a twice-owned stove, I'm sure I can get more for it on the open market than I could from the dealer. It's a great little stove, just not capable of doing what I'm asking of it. I DO WISH the stove manufacturers would tell the truth about the capacity of their stoves, though. Even this little guy should, by their rights, be able to heat my small farmhouse, but it simply can't.
  13. Backwoods Savage

    Backwoods Savage Minister of Fire

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    gyrfalcon, you mentioned hickory. If you can get all hickory when you buy, you are a master buyer indeed! That for sure is some of the very best of the best. You won't get a hotter stove but you won't be opening that fire door so often.
  14. Duetech

    Duetech Minister of Fire

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    The following link will help you select from various woods to burn. http://www.chimneysweeponline.com/howood.htm Higher btu out put usually means a longer burn but with open draft all woods burn quicker than we like though. Dense woods burn with better heat for longer periods. The problem with open draft besides length of burn and the cash flow needed to support it for higher sustained temperature output is safety. Dense woods will roast a chimney as part of the unburned gasses from the fire will burn in the chimney and turn the pipe cherry red and can cause the chimney to become a potential fire hazard. Some dense woods will also damage the stove with the heat the can generate. Perhaps your best friend would be a box fan that can force the heat from room to room. I've built a partial sheet metal shroud around a wood stove and put a blower on it to force warm air downward with pretty good results. Dampers can extend the length of burn and help maintain optimum output but cause lower chimney temps and more frequent chimney cleanings. :eek:hh:
  15. GaryS

    GaryS Member

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    Hickory sure does get awful hot compared to oak. Maybe that's just my perception though.
  16. Shipper50

    Shipper50 Minister of Fire

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    I burned hickory last winter and not sure how seasoned it was, but it didn't put out the heat the white oak I burned last month. I do have some seasoned hickory stacked for this winter and will burn it after the first of the year and will see how it rates.

    Shipper
  17. Jake

    Jake Member

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    I sometimes get hardwood flooring scraps of exotic woods like cumaru, ipe, and brazilian cherry.

    because of their density, a few pieces can get my stove to the red area, where as red oak / white oak scraps take 1/2 a stove full to acheive the same thing
  18. chad3

    chad3 Feeling the Heat

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    I'm still really thinking about going with the soapstone top for my Oslo. They sell a top from Jotul that covers the seam on the top giving you a better of both worlds. Really looking into this. Figure the cast will give plenty of heat as it will now, but in the very cold days, the soapstone will give me a bit of lingering heat.
    Might be the ticket.
    Chad
  19. firefighterjake

    firefighterjake Minister of Fire

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    Have you checked with your local Jotul dealer about the soapstone top? My local dealer said they were unable to get that top which makes me think that if I want to go this route that I will have to fabricate my own.
  20. smokinj

    smokinj Minister of Fire

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    hedge apple!(osage orange)
  21. MarcM

    MarcM New Member

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    I have a similar situation, in that I'm using a soapstone stove (Heritage) in an old farmhouse.

    If you're operating your stovetop consistently at 400 degrees, I'd say that's about right for soapstone. That's about cruising temperature. The thing you want to remember about soapstone is you're limited by what information you can discern by measuring the temperature of the stovetop because of its thermal lag. It won't tell you much about what's going on inside the stove at the same time you're reading the temperature if you're not operating it in a quasi-steady state because of the high thermal gradients the stone is capable of producing. That's why I'm not too comfortable taking mine much above 450.

    You might be able to get a little more heat out of your stove but it doesn't sound like the extra you have left to go is going to make a nigth and day difference like you might be looking for. I'd look elsewhere besides the heat source at this point, like sealing up drafty windows and doors, stuffing insulation anywhere you can... sealing off parts of the house you aren't going to use, etc.

    It's amazing what putting $30 into weather stripping and window plastic will do for an old house's heat retention.
  22. gyrfalcon

    gyrfalcon Minister of Fire

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    Thanks very much for the good advice. This small house does have decent insulation (and foot-thick walls on its two longer sides), and it's been weatherstripped, thermal curtained, etc., pretty well. The windows in the main room of the mostly open first floor are old and replacing them would be about the only thing that would make much of a difference, but that kind of investment is beyond me financially and probably wouldn't come close to paying off at this point in my life. I could plastic the windows, but I'd honestly rather be a little chilly, or spend a bit more on oil heat supplement, than lose the wonderful clear views of the mountains and fields, etc.

    I do realize I'm not going to get that much more heat from this stove, but that difference between the steady 400 and even the occasional short periods of 450 does have a larger impact than you'd think. I'm going to see about putting in a flue probe thermometer to try to figure out what it is that takes it up to that higher temperature. As it is, I haven't been able to make much sense of it.

    As I say, I'm clearly understoved, having bought this mighty mite second hand a few years ago when oil prices were reasonable and I had no thoughts of using it for more than the occasional cozy fire.
  23. MarcM

    MarcM New Member

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    Well, it's good you're well insulated. I still wouldn't put off the idea of the window plastic.... The shrink to fit stuff is pretty much as clear as glass. I put it on several of my windows and don't notice it most of the time. I had better luck with a heat gun than a hairdryer, if you do give it a try... but then I've never been accused of underdoing anything.
  24. gyrfalcon

    gyrfalcon Minister of Fire

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    Good to know. Maybe I'll try one and see how it goes. Thanks.
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