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Backup water heater, which boiler and heating system.

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by Beno, Dec 12, 2007.

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  1. Beno

    Beno New Member

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    1. I need to decide what backup water heater to choose with a gasification wood boiler. I'd rather not use oil, to save room space, maintanance and insurance costs. I was thinking of a tankless electric water heater. I plan to heat only with wood, so the electric water heater will be only for emergencies. Is this a good plan? What electric heater shall I choose?
    The heat loss of our house is less than 90000BTU/h. (Ottawa, Canada)

    2. I'd like to choose a reliable wood boiler, I noticed that Tarm offers a 20 years warranty. Is this preferable to EKO? I guess the location is not a factor, they ship everywhere.

    3. I need to decide between radiant floor heating and hot water baseboards. Which one is better? I'll have 9 ft ceiling or possible cathedral ceiling.

    Thanks,
    Beno

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  2. Eric Johnson

    Eric Johnson Mod Emeritus

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    I have an ordinary electric water heater that I bought when my gas unit died. I shut off the breaker during the heating season and just use the tank to store and distribute DHW heated by the wood boiler.

    I think you can take those warranties at face value. I suspect somebody will be around in each case to honor the warranty. My thinking is that you will work out any bugs in the first five years, after which time there are so many variables (how it's piped, maintained, etc.) that recovering anything is going to involve negotiation in any event. But I think a 20-year warranty is a pretty good deal in any case.

    Infloor radiant all the way. I'd take cast iron radiators after that, with baseboard coming in dead last. Well, just ahead of forced air.

    Aside from the superior comfort, the nice thing about in-floor radiant, if you have a heat storage tank, is that you can use much cooler water than with the alternatives. If it takes 160 degree water for baseboards to work right and only 80 degrees (sorry about the English measurements) for infloor radiant, you can draw your tank down a lot farther and still stay warm compared to baseboards. This means your tank effectively holds much more usable heat, and the Delta T will be much higher (70 to 180) for more efficient heat transfer when charging up the tank.
  3. Nofossil

    Nofossil Moderator Emeritus

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    That's a passel of questions. For the hot water, are you thinking of having a storage tank heated as another zone or via a sidearm HX? Are you assuming that the backup system is something you would only use during the warmer months?

    I can't speak to the relative merits of Tarm vs. EKO. I have an EKO, but that's mostly because it was substantially less expensive, and it was available when I wanted it. I haven't heard bad things about either brand, though I think the 'fit and finish' on my EKO isn't quite as good as the Tarm.

    Radiant is preferable in general, and especially so if you're planning on heat storage. The conventional wisdom is that gasification boilers should run at full output and shut down when they are not needed. Storage lets you extend the time between firings to days in some cases. Radiant can use much lower temp water from your heat storage, so you can go longer between firings.

    Good luck on your project. I've made an attempt to document what I've done on my site - link is in my signature below.
  4. Nofossil

    Nofossil Moderator Emeritus

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    Dang - Eric answered while I was typing. I guess I just have to learn to type faster. Fot the record, I agreed with what Eric said before I saw what he had written especially since there was no epoxy involved this time ;-)
  5. velvetfoot

    velvetfoot Minister of Fire

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    Would a bank give you a loan with only wood heat?
  6. Beno

    Beno New Member

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    Thanks for the answers. I plan to have a powerful tankless electric water heater for backup, so it's not "wood only".
    I plan to have an indirect or, if the space permits, a large storage tank. One way or another, they will provide DHW year round. Now I need to check prices and sizes. Thanks!
  7. Reggie Dunlap

    Reggie Dunlap Feeling the Heat

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    As a builder I get asked the radiant versus baseboard question all the time. Most of the time the best approach seems to be radiant in the basement, radiant on the main floor, and baseboard on the second floor. That's assuming your bedrooms are on the second floor.

    On the main floor you will not get the full benefit of radiant unless the tubing is in a concrete overpour. Don't let anyone talk you into a staple-up installation. You need the concrete to act as a thermal mass. We lay 2x2's on 12" centers on top of the plywood subfloor with the tubing run between them. Then we pour 1 1/2 inches of lightweight concrete over the tubing. The 2x2's are nailers for wood flooring, you don't need them for tile or carpet.

    Hope this helps,
    Reggie
  8. Beno

    Beno New Member

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    Thanks Reggie, we will go with ICF walls and concrete floors, slab on grade (no basement) and Hambro for the second level. So the in-floor radiant will work well in concrete, as well as the solar radiation for this matter (passive solar home).
  9. Tarmsolo60

    Tarmsolo60 Feeling the Heat

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    tankless electric water heaters don't give you much of a hot waterflow rate. If you went with something like a NTI Trinity combi gas boiler it would not take much space as it is a wall hung unit that weighs about 80 lbs it is direct vented, sealed combustion and will give you hot water and also backup heat for your house if you were away. it could easily tie into your hydronic system and there would be no stanby losses if it wasn't being used.
  10. Eric Johnson

    Eric Johnson Mod Emeritus

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    Did I mention, Tarmsolo60, that it's nice to have another heating pro on the board?
  11. Beno

    Beno New Member

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    Unfortunately we will have no gas there, the only options are electric and eventually oil.
  12. Tarmsolo60

    Tarmsolo60 Feeling the Heat

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    thanks, seems like a good group of people on the forum. It's good to have access to everyones knowledge and experiences especially on the gasfication boilers. Before I joined last week I didn't know anyone with a gasifyer besides me. I think the ultmate backup to a wood hydronic system is the NTI Trinity combo. That to me is the best of both worlds. I do mostly higher end 2nd homes so wood boilers don't get installed on any of my jobs.
  13. Tarmsolo60

    Tarmsolo60 Feeling the Heat

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    the NTI can burn propane also, even comes with the conversion kit. you wouldn't even need a indirect to store your DHW. It modulates the flame depending on outside temp and is very quiet.
  14. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    If you want to actually heat your house with it, and use electric, a tank will be better than a tankless.

    If LP (propane) is available as an option, a Noritz tankless would be the best bet. I don't think anyone else makes a gas tankless as good as they do, and theirs are actually rated for heating use, if you want to (using a tankless for space heating, in most other cases, immediately voids the warranty).

    There's no better heat than radiant.

    Panel radiators on second floor :)

    Underfit with aluminum transfer plates will give the same efficiency as overpour, with better response time. Of course, transfer plates are expensive (purchase, and labor). Overpour definitely saves on the labor.

    Warmboard is the best way to do radiant, IMO.

    Or just throw out the kit and adjust the input screw (which you have to do anyway) to get it running right :)

    I was skeptical when the NTI rep told me that, but a subcontractor on a job was looking at the kit and ended up absentmindedly walking off with it, so I just did like the rep said and it worked great.

    They're definitely nice boilers, and the ability to convert from NG to LP by turning a screw is a definite plus...

    Joe
  15. leaddog

    leaddog Minister of Fire

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    [quote author="BrownianHeatingTech" date="1197528254"][quote author="Beno" date="1197499554"]

    Underfit with aluminum transfer plates will give the same efficiency as overpour, with better response time. Of course, transfer plates are expensive (purchase, and labor). Overpour definitely saves on the labor.

    Warmboard is the best way to do radiant, IMO.

    I was wondering if you use the staple up method could you use foil/bubble foil under and would the foil act as a transfer medium. It would be cheaper and very easy to staple up. Then you could use fiberglass or what ever. I have my kitchen, dinning room, living room over my garage and i'm trying to think of a easy way to go radiant.
    leaddog
  16. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    The aluminum is really necessary to transfer the heat most effectively. Of course, plenty of folks can and do run tubing stapled to the underside of the wood, with no transfer plates at all. It just reduces the efficiency, since the water in the tubing needs to be hotter to get the same amount of heat transfer to the floor.

    You definitely need to insulate under it, no matter what you do. You want to leave an air gap, so there is no direct contact between the tubing and the insulation, or it will transfer heat to the insulation.

    Joe
  17. Beno

    Beno New Member

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    The problem with propane is that you need this huge tank in the backyard for the propane. An electric water heater with tank makes sense, for occasional backup heating/DHW.
  18. leaddog

    leaddog Minister of Fire

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    Then the aluminum foil on the foil/bubble/foil wouldnt have enough mass to do any good at heat transfer? I thought it might be enough to spead the heat over the wood more evenly.
    leaddog
  19. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    If you're using very little, you only need a small tank.

    It's not so much the mass, as the cross-section of the aluminum. Heat requires "space" to flow through, for a simple explanation. Getting heat to transfer through the foil would be like trying to put out a house fire with a garden hose - the water/heat can't "flow" through the small space.

    If you had access to the equipment and scrap aluminum, I've seen aluminum siding used...

    Joe
  20. leaddog

    leaddog Minister of Fire

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    The other problem with propane here in Michigan is you have to use a minimum of 200gal or they charge $180 tank charge. I had a propane boiler that I'm useing for back up so I ended up buying my tank but it was very hard to find ANY dealer to sell one. They want you to be locked into them as there is more money in leasing. They then can charge what they want. A lot of people around here keep changing leases as the dealers will give teaser prices untill they get you signed up then the price keeps going up and up. If you don't like there price and tell them to get the tank they CHARGE YOU to pump out the tank that you paid for. So if you change suppiers you either lose some of the propane you paid for or you are out waiting for the new suppier to put in another tank. They usually are a month behind puting in a tank. So here they kind of got you where it hurts. It cost me this summer $1.65 a gal to fill MY tank and if I keep there tank it was $2.35 plus the $180 I paid for rent.
    leaddog
  21. Tarmsolo60

    Tarmsolo60 Feeling the Heat

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    Here people are buying their own burial tank, then can buy fuel cheaper from whichever company they want to(at a pretty substanstial savings) and all you see is a small access tub sticking out of the ground. After you fill the tank 4 or 5 times the money you save on the gas is enough to pay for the initial purchase of the tank.
  22. Tarmsolo60

    Tarmsolo60 Feeling the Heat

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    I can see using a electric water heater for DHW but i'm not understanding how that is going to be backup heat. Are you talking about an electric boiler?
  23. Beno

    Beno New Member

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  24. Tarmsolo60

    Tarmsolo60 Feeling the Heat

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    I learned that a NTI training course I went to. I just always take the 10 min to install the lp orifice. Then when you put the NTI supplied converted by "your name" sticker on the boiler your butt is covered if some meathead comes behind you a screws with it. You can say you converted it just like the manual tells you to.
  25. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    That's for tank water heaters, not tankless.

    If you look under each "fuel," there is an energy factor. The 0.57 for propane is for a tank heater. Most decent tankless heaters are over 0.80 on the energy factor. Using their numbers, if that same propane cost were given an EF of 0.80, it would end up being less than $200 per month, I think.

    Yeah, I would have, if I had the kit :)

    Joe
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