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)

? which furnace????

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by dookits13, Dec 6, 2007.

Thread Status:
Not open for further replies.
  1. dookits13

    dookits13 Member

    Joined:
    Dec 6, 2007
    Messages:
    9
    Loc:
    NE Ohio
    hi everyone i am new fairly new to wood/coal heating , but am very interested in heating my home with it!!! i recently bought an old farm house , which has an oil furnace , works fine but its breaking the bank!!!!! So as of late i've been researching on the best furnaces out there. Usally whichever dealer you talk to theres is the best , thats why i am asking here to get real world honest feedback ! Also which way or ways are the best to install them . After talking to a couple of local dealers , Harman , Woodchuck , and Brunco seem to be in the running with Harman leading the way ?Some info. on my home : approx. 2300 sq. ft. with approx. 9 ft. ceilings - 2 stories . Any ideas on the #of BTU's needed ? my current furnace is rated at 120,00 , and all of the manufactures have different ratings?? ie. the Brunco says 120,00 will heat 1800 sq. ft, and Harman says 120,000 will heat 3200?? big gap there ??? The Harman dealer told me that the smallest furnace rated at 90,000 BTU's ( 2200 sq.ft. ) will work fine ??? I know theres a lot here but thanks for bearing with me , i want to make the best choice !! any help or info GREATLY appreciated!!!!! thanks joe

    Helpful Sponsor Ads!





  2. FireJumper

    FireJumper New Member

    Joined:
    Dec 14, 2005
    Messages:
    121
    The only thing I'm going to say here is this.....If your home is rated at 2300 sq ft don't settle for one that can handle 2200 sq ft. Go to the next size up. You will find on the colder days you're gonna be looking for more heat then the unit can handle and you'll end up over firing the unit. Alteast with a bigger unit you'll have a little extra heat factor if or when you need it.
    Just a side note though, most folks that I have talked to that have owned or own a Harman coal/wood furnace swear by them. Good luck!
  3. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

    Joined:
    Oct 5, 2007
    Messages:
    1,253
    Loc:
    Northwood, NH
    2300 square feet, unless you have something really crazy going on (like a desire to leave windows open during the winter) can be heated by 95kbtu or less. Probably less.

    Joe
  4. pdboilermaker

    pdboilermaker New Member

    Joined:
    Nov 7, 2007
    Messages:
    140
    Loc:
    North Central Indiana, Kokomo
    Go down a few threads on the next page and check out the "Outside woodboilers, and only outside wood boilers" thread. It has info about some of the different brands gives their pros and cons
  5. pnich

    pnich New Member

    Joined:
    Dec 7, 2007
    Messages:
    1
    I'm also new to the wood furnace game and have similar questions. I'm currently heating my house with two woodstoves (a Napoleon and a Pacific Energy) which combined are more than enough. However, they do require re-fill every 3-4 hours to keep the house at a toasty temperature (and that's not easy in -25C Ottawa Canada winters). I've seen lots of posts about wood boilers and I was hoping to have one inside the house (remove my Pacific Energy and slap the wood furnance under the existing 8inch chimney), but lots of folk here seem to feel that having a wood furnace indoors is just plain wrong. Tarm and Greenwood, among others, claim that indoor installation is fine and frankly I'd prefer to not have to go outside to re-load the furnance, but the consensus here is that I should build an out-building instead. Why is that the case? What are the manufacturers not saying?

    My initial favourite was the Tarm but I've little space in my basement for the water tank (and less space in my wallet for the extra cost), and then I looked at the Greenwood but various posts in here (refractory cracking, smoke, poor efficiency) and that got me concerned as well. The Garn looked interesting, particularly the side venting/low emissions, but it's a monster! Any advice?
  6. Beno

    Beno New Member

    Joined:
    Feb 26, 2007
    Messages:
    175
    I am also in Ottawa area. If you already have ducts you can use a Caddy furnace (there is a long thread about Caddy going on).
    Do you have a dealer for a wood boiler in our area?
  7. Nofossil

    Nofossil Moderator Emeritus

    Joined:
    Oct 4, 2007
    Messages:
    3,398
    Loc:
    Addison County, Vermont
    I have an EKO 25 gasifier boiler in my basement. Pretty civilized. Tending it in my pajamas is nice.
  8. Gibbonboy

    Gibbonboy New Member

    Joined:
    Oct 3, 2006
    Messages:
    267
    Manufacturers' claims to how many square feet their products will heat are entirely meaningless. None use the same method of calculating, so there's no comparison, not to mention that 90% of those numbers are wildly optimistic. I live in northern Pennsylvania, and have a furnace rated at 140K BTU's. My house is 1400 square feet, and when it was 0 degrees the other night, it was kind of chilly with the stove burning at the "all-night" level. Remember also that those BTU numbers are the MAX output, meaning you have them full of dry wood burning right at the fringe of overfire, all the time, which is impossible except in a lab.

    If you have the money to afford a Harman, look very hard and seriously at the Caddy- about the same money and it will burn much cleaner, all things considered. Harmans are wonderful units, I know many people that have had them for 20 plus years, but they're old-tech. Besides, any device that tries to serve two differing goals will meet neither- if you want to burn wood, get a wood furnace.

    I have the USSC 1600M furnace, and I do love it. But it is the same "technology" as the Harman- just an "airtight" stove, no secondary burn at all. In a few years I plan to upgrade to a Caddy or whatever happens to be available at the time that is clean-burning. Maybe by then we'll all have our Mr. Fusions in the basement!

    Personally, I look at having a wood furnace (or boiler) in the basement as the best possible situation. You don't have to go outside to tend the fire, and at the same time, you're not trying to heat the masonry/stone/dirt of your foundation with all those BTU's you worked so hard to capture. Best of luck.
  9. Eric Johnson

    Eric Johnson Mod Emeritus

    Joined:
    Nov 18, 2005
    Messages:
    5,705
    Loc:
    Central NYS
    I've got mine in an outbuilding and I like it there, but it could easily go into the basement and work pretty well. I think you'd need some sort of exhaust hood if you're going to run it without hot water storage, however, since they tend spill smoke (mine does, at least) if you open the loading door mid-cycle. With adequate storage, you can pack it to the brim and foget about it until the end of the cycle. The blower makes some noise, but not much. The low rumble of gasification in progress is pretty cool. I'd like to be able to hear that emmanating up from the basement--it would make me feel even warmer.
  10. rodneydenise

    rodneydenise New Member

    Joined:
    Dec 7, 2007
    Messages:
    2
    Loc:
    Prescott, AZ
    I live in Prescott AZ. I'm new to the wood boiler world, because I can get all the pine wood I need. I'm looking at a EKO 40. I have floor heat in a 2000 sq ft. house. I don't want a noise boiler either.
    I was going to use it for domestic water too.I was only going to put a 50 or 100 gal. storage tank in.
    I also been looking at a greenwood and new horizon. I'm looking for indoor boiler. I would greatly appreciate some advice
    Thanks
    Rodney
  11. Eric Johnson

    Eric Johnson Mod Emeritus

    Joined:
    Nov 18, 2005
    Messages:
    5,705
    Loc:
    Central NYS
    Well, Tarm, EKO, Econoburn, Wood Gun and BioMax all make indoor gasifiers, and I believe they're of uniformly high quality and suitable for indoor use. I wouldn't to hesitate to put my EKO in the basement, but now that it's in the barn, I really like it there. I don't worry about mess or smoke or noise. If it was in the basement, I'm confident I could get it working just as well.

    Nofossil has his EKO 25 in the house and rreinhart has a new BioMax in his basement, so hopefully they'll share their observations and suggestions. Most of the Tarm users on this forum have indoor installations, I believe. Oh yes, and Maine has a Black Bear Boiler in his basement. Pretty cool.

    Welcome to the Boiler Room, by the way. Hang around here long enough and you'll learn all you need to know about gasification boilers, and other technologies as well.
  12. rodneydenise

    rodneydenise New Member

    Joined:
    Dec 7, 2007
    Messages:
    2
    Loc:
    Prescott, AZ
    We don't have a basement. We are planning to put the boiler in the garage. I was wondering if a 50 gallon storage tank would be enough for floor heat and domestic water. How big is your door opening on the boiler? Do you know if a EKO 25 has a smaller door than an EKO 40?
  13. Eric Johnson

    Eric Johnson Mod Emeritus

    Joined:
    Nov 18, 2005
    Messages:
    5,705
    Loc:
    Central NYS
    You might want to check your local codes regarding putting a wood-fired boiler in a garage before you spend any money.

    For specific information on EKOs, I would check either with the importer, http://www.newhorizoncorp.com or the dealer I bought mine from, http://www.cozyheat.net. Don't believe the specs on wood size that New Horizon has in its online manual and that chart. You can use much bigger wood than what is specified, at least as far as diameter is concerned. Ditto with the chimney height calculations. dave@cozyheat.net will give you the actual numbers for specific models.

    Currently, I'm heating my big old house in upstate New York with an EKO 60 and since my 1,000-gallon tank isn't hooked up yet, my only "storage" is a 50 gallon electric hot water heater. Lots of storage is always desirable with a gasifier, but if you size the boiler right, you can get by without it. Do me a favor and burn some Teddy Bear Cholla cactus when you get that boiler. Revenge for the pain inflicted during my hike in the hills around Surprise (it was!) AZ.
  14. Nofossil

    Nofossil Moderator Emeritus

    Joined:
    Oct 4, 2007
    Messages:
    3,398
    Loc:
    Addison County, Vermont
    I think the 25 is smaller - my usable door opening is about 10" x 14".

    50 gallons is way too small for any kind of floor or space heating. The formula is simple - 1 BTU heats 1 pound of water 1 degree. A 50 gallon tank weighs 400 pounds. If you can heat it to 175 degrees and get useful heat out of it down to 100 degrees, then it can store 30,000 BTU. Even on my little EKO 25, that's less than 1/2 hour of boiler output.

    It's worthwhile to do an energy study (or have one done) to get a good estimate of how many BTU/hr your house needs. In our climate, I need up to 30,000 BTU/hr in the cold snaps. I use an 880 gallon tank, which is not quite as large as I'd like.
  15. Beno

    Beno New Member

    Joined:
    Feb 26, 2007
    Messages:
    175
    About the heat storage. Let's say that I have radiant floor, in a concrete slab. Why can't I use the huge thermal mass of the concrete to store the heat? I could have an 120 gal indirect, for heating and DHW, and warm the slab few degrees higher when the boiler burns wood.
  16. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

    Joined:
    Oct 5, 2007
    Messages:
    1,253
    Loc:
    Northwood, NH
    You can, to some extent. Your radiant slab should be "operating" at 80 degrees or so, for effective heat transfer to the room. You can heat it up to about 85, before it starts to be uncomfortable for your feet. Those few degrees will account for a small amount of heat storage. Of course, it will be radiating into the room, so you may overheat the house.

    Joe
  17. Nofossil

    Nofossil Moderator Emeritus

    Joined:
    Oct 4, 2007
    Messages:
    3,398
    Loc:
    Addison County, Vermont
    Any thermal mass inside the house will cause the indoor temperature to change more slowly, all things being equal. That's good, and it will tend to increase the time that you're still comfortable after the boiler has gone out.

    Storage, though, is a heat source that can be used to increase your indoor temps when they start to drop. Part of the goal in designing any system is to limit the indoor temperature swings to an acceptable range. Thermal mass helps, and storage extends the time even farther for the same amount of indoor temp variation.
  18. Beno

    Beno New Member

    Joined:
    Feb 26, 2007
    Messages:
    175
    Yes, this is exactly what I meant. Instead of having a steady 80 degress of the slab I could have something between 75 and 85 degrees. Will the 120 gal indirect be able to heat in this scenario? We will have 3600 sq.ft. of 4" concrete floor (slab on grade + Hambro at the second level). This is a huge thermal mass, probably more than any water tank can store. I will probably have to adjust the thermostat for radiant heating accordingly.
    Can you recommend some websites/books that help designing and sizing the storage water tank? (After I have the heat loss done)
  19. Nofossil

    Nofossil Moderator Emeritus

    Joined:
    Oct 4, 2007
    Messages:
    3,398
    Loc:
    Addison County, Vermont
    By my quick back-of-the-envelope calculation, there's a difference of about 350,000 BTU between your slab at 75 degrees and 85 degrees. That's the same as heating a 500 gallon storage tank by about 85 degrees. Water stores much more energy per pound and per cubic foot.

    Slab and thermal mass are good things except when you need to warm them up quickly.

    Another way to look at it is that a 500 gallon storage tank would allow you to reduce the temperature variation in your house by 50% and still go longer between fires. That's why people do the storage thing.
  20. Beno

    Beno New Member

    Joined:
    Feb 26, 2007
    Messages:
    175
    The thermal mass of concrete is half of water's. Another question will be how long will take the concrete floor to cool 10 degrees? If it's more than 24h (or even 12 h), that's OK with me.
    The main reason I'd rather go with a smaller tank is the space issue. The house will have no basement, and the utility room will be 8 ft wide. A 120 gal indirect is about 2 ft in diameter. How big is a 600 gal tank?
  21. Nofossil

    Nofossil Moderator Emeritus

    Joined:
    Oct 4, 2007
    Messages:
    3,398
    Loc:
    Addison County, Vermont
    The answer to how long it takes is based on your house's heat loss. If it's 35,000 BTU/hr then it will take 10 hours. You'll know pretty soon in any event.

    I ended up putting my storage tank outside and building an insulated enclosure for it.

    My brother heats his superinsulated house using a radiant slab, gasification boiler, and a few 50 gallon plastic barrels just to extend the heat a little. His system is unpressurized. Works good, but you need a fire more often and you have to be careful not to overfire. Didn't take him long to get it figured out.
  22. Eric Johnson

    Eric Johnson Mod Emeritus

    Joined:
    Nov 18, 2005
    Messages:
    5,705
    Loc:
    Central NYS
    What happens to an EKO when you overfire it, nofossil? I don't think I've ever come close, though it did get up to 83 the other night.

    And what are the consequences? Warped bypass damper, or worse?
  23. Beno

    Beno New Member

    Joined:
    Feb 26, 2007
    Messages:
    175
    Our house will be very well insulated, ICF, passive solar, insulation under slab, Energy Star windows etc.
    Can you please specify the diameter of your 880 gal tank? What do you do during a power outage?
  24. Nofossil

    Nofossil Moderator Emeritus

    Joined:
    Oct 4, 2007
    Messages:
    3,398
    Loc:
    Addison County, Vermont
    My brother doesn't have an EKO - he has the home-brewed work of art. In this context, overfire means putting more wood in than you need to get the house up to temp. In his case, there's no thermostat and no provision for idling, so the house will get too hot.

    Mine just idles, though it gets scary hot if you have a really good fire going with a lot of small wood / large surface area. There's enough draft to pull air through the blower and keep gasification going even with the fan off, and I've had temps near boiling at the oulet, and it probably was boiling in spots. Hasn't been a problem since I added the storage tank, of course.
  25. Nofossil

    Nofossil Moderator Emeritus

    Joined:
    Oct 4, 2007
    Messages:
    3,398
    Loc:
    Addison County, Vermont
    If I remember right, my tank is roughly 5' by 7' oval, and about 4' high. I use deep-cycle marine batteries and an inverter. There are more details than you could ever want on my site - the link is in my signature below.
Thread Status:
Not open for further replies.

Share This Page