1. Welcome Hearth.com Guests and Visitors - Please enjoy our forums!
    Hearth.com GOLD Sponsors who help bring the site content to you:
    Hearthstone Soapstone and Cast-Iron stoves( Wood, Gas or Pellet Stoves and Inserts)
    Caluwe - Passion for Fire and Water ( Pellet and Wood Hydronic and Space Heating)

Gasification vs. Outdoor boiler How much wood?

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by Snow4days, Sep 19, 2011.

  1. Snow4days

    Snow4days New Member

    Joined:
    Aug 29, 2011
    Messages:
    13
    Loc:
    Mid Michigan
    Do you burn less wood per year in a gasification boiler?

    Helpful Sponsor Ads!





  2. 2.beans

    2.beans Minister of Fire

    Joined:
    Mar 22, 2008
    Messages:
    520
    Loc:
    new hampshire
    really? you need to do some reading.
  3. stee6043

    stee6043 Minister of Fire

    Joined:
    Aug 22, 2008
    Messages:
    2,346
    Loc:
    West Michigan
    Ha. Yes. I burn 1/3 as much as a friend with roughly the same footage.
  4. Frozen Canuck

    Frozen Canuck Minister of Fire

    Joined:
    Dec 14, 2009
    Messages:
    865
    Loc:
    North central Alberta, Canada
    Plenty of threads here to help you with that Q. Short answer is yes absolutely. Less than an old style wood burning non gaser boiler, less than any OWB you care to name. The best of these units repesent 40 years of engineering/design improvements & many have reached the theoretical limit of eff in a wood burning appliance. You dont want to collapse & condense the flue gases in any wood burner (toxic). So yes, until a technological breakthrough happens many of the respected units are as good as it gets from an eff standpoint.
  5. flyingcow

    flyingcow Minister of Fire

    Joined:
    Jun 4, 2008
    Messages:
    2,353
    Loc:
    northern-half of maine
    I priced out an E-classic from central boiler. The numbers supplied to me (from the E-Classic salesman) comparing it to oil was; 1 cord of seasoned wood = 100 gals of oil.


    A gasser: 1 cord of seasoned wood = 150 gals of oil, sometimes closer to 175 gals. And I am closer to the 175 mark the last year or so. The price of a gasser with storage was the same as an E-classic.
  6. Reggie Dunlap

    Reggie Dunlap Feeling the Heat

    Joined:
    Dec 13, 2005
    Messages:
    314
    Loc:
    Northern Vermont
    In my Tarm I burn about half the wood as guys around here with OWB's. That's assuming roughly the same heating needs.

    Flyingcow- did you ask him how gallons of oil per cord of soaking wet green hemlock? A lot of the OWB's could be much more efficient if they burned dry hardwood.
  7. flyingcow

    flyingcow Minister of Fire

    Joined:
    Jun 4, 2008
    Messages:
    2,353
    Loc:
    northern-half of maine

    No doubt on the green wood. But in Maine we can only buy EPA compliant OWb's. The E-Classic needs dry wood anyways, so if you got to burn seasoned wood, why not burn less in a gasser. I have no hardwood available on my property, so I went with the unit that will burn less.
  8. Snow4days

    Snow4days New Member

    Joined:
    Aug 29, 2011
    Messages:
    13
    Loc:
    Mid Michigan
    I already had the idea from what I had red. I just wanted to hear it from you guys. Much better information from those who have been doing this a while.
  9. flyingcow

    flyingcow Minister of Fire

    Joined:
    Jun 4, 2008
    Messages:
    2,353
    Loc:
    northern-half of maine
    IMO the key to this is always have, at least a yrs ahead of wood. Especially if you want a gasser. Trust me, they don't run on semi-seasoned wood. 20% and less on moisture.
  10. lampmfg

    lampmfg Member

    Joined:
    May 16, 2011
    Messages:
    76
    Loc:
    Tower, MN
    What is the impact on total wood consumption/yr. if you use a super efficient furnace like our Vapor Fire?

    Here are the important numbers that need to be examined: 1 gal. #2 fuel oil = 140,000 BTUs; 1 gal. propane - 91,500 BTU's; 1 cord paper birch wood = 21 M BTU's; 1 cord red oak = 25 M BTU's.

    VaporFire furnaces were tested to have an overall efficiency as high as 85%, 99.4% combustion efficiency, less than 1 gr/hr of emissions, 99% smokeless burn cycles, internal flue temperatures 285-400 degrees F., and external flue temperatures 150-250 degrees F. VaporFire furnaces have been used for over 25 years with no condensation issues whatsoever, because the flue temperatures are still high enough to support a natural draft system when installed according to our written directions.

    A good estimate for oil usage for a heating season would be 500-1,000 gal., with lots of variables. We'll take a look at an average home using 750 gal. of oil for the heating season. 750 gal = 105 M BTU's. If a wood furnace was 100% overall efficient, which is not possible, it would take : 105 M BTU's /21M=5 cords of birch or 105 BTU's/25M=4.2 cords of oak.

    Our VaporFire furnace at 82% average overall efficiency would be; 105 M BTU's/(21Mx82%) = 6.09 cords of birch or 105 M BTU's/(25 M x 82%) = 5.12 cords of oak.

    Most manufacturers struggle to hit 60% overall efficiency, but we'll look at their results based on 60%. 105 M BTU's/(21M x 60%) = 8.33 cords of birch or 105 M BTU's/ (25M x 60%) = 7 cords of oak.

    Therefore, as you can see, using our efficient VaporFire furnaces will, without a doubt, use less wood to deliver the same amount of BTU's you'd require in oil or propane for the heating season then a less efficient furnace would. The other big advantages are minimal air pollution, longer more even burns, and minimal creosote accumulation from 99% smokeless burn cycles. The safely aspect is also huge in saving homes and lives.

    I'm quite sure alot of manufacturers will be very surprised to see their furnace test results when regulations come into effect in 2013-14. They're not going to believe how much air pollution and wasted wood their so called efficient furnaces have produced. Many manufacturers will have to fold or redesign their furnaces quickly. I'm thankful that I invested the time, effort and money in preliminary testing so that our company is prepared for the future. We knew the regulations were forthcoming.
  11. flyingcow

    flyingcow Minister of Fire

    Joined:
    Jun 4, 2008
    Messages:
    2,353
    Loc:
    northern-half of maine
    lampmfg....wish you the best.
  12. heaterman

    heaterman Minister of Fire

    Joined:
    Oct 16, 2007
    Messages:
    3,039
    Loc:
    Falmouth, Michigan
    Simply put, with all other things being equal, a decent wood boiler (gasification unit with storage or something like a Garn) will use between 30-60% less wood than a typical outdoor wood burner.
    Actual lab tests, not manufacturer test, of OWB's a few years ago revealed efficiencies between 28-41% for the units tested. And yes, the units tested included the major players in the OWB field.

    Down draft gassers with storage will routinely and realistically hit 75-80% under normal field conditions. Pay little attention to manufacturers claims of anything above that. It's not going to happen unless you burn 15%MC wood and clean your boiler weekly.


    I'm just sayin.........
  13. lampmfg

    lampmfg Member

    Joined:
    May 16, 2011
    Messages:
    76
    Loc:
    Tower, MN
    Flying cow what are you crying about it's good information isn't it?
  14. I thought so.
  15. muncybob

    muncybob Minister of Fire

    Joined:
    Apr 8, 2008
    Messages:
    1,997
    Loc:
    Near Williamsport, PA
    A friend of mine that use to have an OWB saw my wood stacks and quipped "I thought your boiler was so efficient..that looks like how my wood stacks looked" to which I replied that my stacks was my heat/dhw for the next 3 years...your stacks were for just 1 year.

    In 4 years I have yet to burn more than 5 cords/yr...based on my previous average oil consumption that would be about 160/gal per cord, although it's actually higher than that since we did not have the additional 900 sq ft on our house when we were burning oil that we have now.
  16. Gasifier

    Gasifier Minister of Fire

    Joined:
    Apr 25, 2011
    Messages:
    3,137
    Loc:
    St. Lawrence River Valley, N.Y.
    Heating a 4200 sq.ft. house and 900 sq.ft. garage, and providing domestic hot water for five people year round in Northern New York year round. All with 10 cord of wood. (or 30 New York Yankee face cord. ;) )

Share This Page