# Wood-fired hydronic furnaces



## Lemms (Jan 24, 2007)

I will be specific so that I don't upset anyone by using the term "wood boiler".. 
So, here I go. We currently have a natural gas "boiler" (hydronic furnace). We purchased a 
pellet stove this fall. However, it doesn't work that well for heating the whole house. We have 
it on the main floor of a ranch home. If we had it in the basement, we might get more even 
heat on the main floor. However, it is what it is. So, we are looking into getting a wood-fired 
hydronic furnace this summer/fall to act as our main heat source. We will use the pellet stove 
as a supplementary heat source in the dining & living room area of the house. And we will use 
our natural gas "boiler" as our backup.
So...I am looking for recommendations on wood-fired hydronic furnaces... One brand that I have 
looked at so far is Greenwood. Any other opinions and/or recommendations would be greatly 
appreciated. We are looking for an indoor hydronic furnace for our basement. So, there is no 
need to suggest an outdoor hydronic furnace. We just don't want one, period.

Bring it on 
Thanks..


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## laynes69 (Jan 24, 2007)

The tarm units are very high quality, gasification furnaces. You can see them here....
http://www.woodboilers.com/wood-gasification.asp
Another one is the Econoburn Boiler which also is a gasification boiler.
http://www.alternativefuelboilers.com/?OVRAW=wood boilers&OVKEY=wood boiler&OVMTC=standard
With something like this It would easily be a main source of heat. The thing about these are they are expensive, but the technology is there. Im sure there are others out there like it. They seem like the way to go if you are looking for a boiler.
One other boiler I have seen, is sold on E-bay, check it out.
http://cgi.ebay.com/coal-wood-boile...6QQihZ017QQcategoryZ41987QQrdZ1QQcmdZViewItem


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## Andre B. (Jan 24, 2007)

Never could understand why one would want to boil wood anyway.  Unless you was fixing to make your own paper.

No nothing about them, but a 100,000BTU unit that weighs 2,400 lbs can't be all bad.
http://www.greenwoodfurnace.com/
http://www.greenwoodfurnace.com/How_it_Works.htm


Been about three years since I was last at the steam show there in Edgar, I should try to make it this year.


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## Lemms (Feb 1, 2007)

Sorry for the long delay in getting back here, but it's been a busy/crazy week since I first posted this. 
Not as many responses as I had hoped, but they have been helpful...  
So, if looking for a wood-fired hydronic furnace, we would be best getting a "wood gasification" unit, rather than the usual boiler? Has anybody had any experiences with one? Are they worth the steep extra cost? As long as we are talking about it... Is a wood-fired hydronic furnace worth the cost over a regular wood furnace? We have hot water heat now and I like it. However, last summer we had central air put in. SO, we now have duct work as well. My brother was telling me to save the money and just tie a wood furnace into the duct work.... I don't know, I like the hot water heat, and it is suppose to be more efficient. But worth the extra cost?
Give me your thoughts...

Andre' B, You should never miss a chance to make it out to the old Steam & Gas Engine Show here in Edgar...


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## Eric Johnson (Feb 2, 2007)

I'm going to be putting in a wood gasification boiler next heating season. Currently I have a Royall (Elroy, WI) 150,000 btu/hr conventional wood-fired boiler (indoor) but it consumes too much wood and produces too much smoke for my situation.

I'm looking at the Eko Model 60 which is a 205 btu/hr gasification unit. The price is about $6,000 delivered, but you will also need some accessories and installation. Tarm gassifiers are great, but you pay a premium. I'm waiting for pricing on the Alternative Fuels boiler line, but I suspect it's similar to the Eko, which is to say between $4,000 and $6,000, depending on the capacity. Because of the vastly better efficiencies and nearly clean burn, I think it makes sense to spend the extra $1,000 or $2,000 to go with a gasifier. It shouldn't cost any more to install than a conventional boiler (Royall still makes a nearly identical version of my 25-year-old rig), and will pay for itself both in lower fuel consumption and pollution, pretty quick.

I'm with you Lemms--I love hot water heat. We have a big, old, drafty farmhouse with cast iron radiators and it's a joy to crank up the heat in the winter. These houses were designed for heating systems that ran on cheap coal, and wood gasification is about as close to that as you can get, IMO. Another thing is an unlimited supply of free domestic hot water. Yes, it's free. I've found you burn less wood if you heat your hot water as well. The water heater acts like water storage, which is more efficient. If you start to reasearch gasification boilers, you'll learn all about heat storage.

Bear in mind that you will need a Class A (double-walled, insulated stainless steel) chimney to hook up any wood-burning appliance in your house.

BTW, my boiler is currently in the barn along with my wood supply. I've run boilers in the basement in other houses, and that's the way to go if you have a good chimney and a basement with enough room to store lots of wood with easy access.

Good luck.


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## Lemms (Feb 2, 2007)

Eric, 
Thanks for the 411...  I will look into the Eko's.  I did look at the Tarm's a little bit already.  Yeah, the Greenwood that I was looking at was about $7000.  That seems a little steep, but I'm still looking...
As for a chimney, I have a standard block chimney those goes from the basement up, and it is in pretty nice shape yet.  So, I should bet set there.  My wood boiler (gasification unit) would be in the basement.



> found you burn less wood if you heat your hot water as well. The water heater acts like water storage, which is more efficient.


I find that interesting...  I'm not quite sure what kind of setup you are talking about, but it sounds interesting...  I am actually looking into a tankless hot water heater.  It runs off of natural gas, but is suppose more efficient that the traditional hot water heater with the 40-60 gallon tanks.  However, if I will be better with what you are describing, I would be interested in that.  Do you have to burn gas all year long then?  I wouldn't care for that...

Anyone else have any other wood gasification brands that they recommend or don't?


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## Eric Johnson (Feb 2, 2007)

All you need to heat your hot water with your wood-fired boiler is some simple plumbing and a heat exchanger. I made my own, buy they can be bought for $100 to $150. An alternative would be to have your boiler fitted with a domestic water coil, which is simply a coil of copper inside the boiler that you circulate water through. It circulates between your existing (40 or 50 gal) water tank and the coil. Free hot water when the boiler is running. The hot water coil is basically a tankless hot water heater, but it's nice to have a hot water tank so that you don't ever run out.

You can revert back to gas or electricity in the warmer months. If you have a gassification boiler and a big water heater or other water storage, you can fire the boiler up once a week to heat up your hot water.

Here's a diagram of how a "sidearm" heat exchanger works. It heats the tank by convection (gravity). The heat exchanger shell is simply another zone on your hydronic heating system, so you use the main circulating pump to get the boiler water to the heat exchanger, and the hot water tank heats up by itself.

And I was wrong about the chimney. Codes will allow you to use a masonry chimney if it's in good condition. I'm not sure if they recommend hooking a gasifier up to a masonry chimney, but I don't see why not. Creosote shouldn't be a problem in any event.


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## slowzuki (Feb 2, 2007)

Creosote no but condensation can be a problem.  Some of the furnaces are designed for short hot burns and the cool exhaust means the thermal mass of the chimney doesn't get up very quick.  This is more of a problem for exterior chimneys.  A ss liner is often speced.

Condensation leads to acid attack on the lime in the mortar, leading to failed chimney.


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## Eric Johnson (Feb 2, 2007)

Tru.dat^^^^


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## greeninsulation (May 7, 2008)

Green Gasification Furnace for the Green Mountain State. Barrett Enterprises announces that the Vermont DEP just added the E 3400 Sequoyah Gasification to its list of smokeless outdoor wood boilers (OWHH) meeting the emission limits in Vermont along with Maine   “Invest in renewable energy and an environmentally responsible heating alternative now and be energy independent says Callie Barrett, President of Barrett Enterprises.  Burning wood outdoors is the safest, most economical, way to heat.  To learn more about this Orange Tag EPA Approved Furnace and other Green Products please visit
www.WoodGasificationFurnace.com


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## deerefanatic (May 8, 2008)

Being this hasn't seen any activity since February of 07, I'd say the above post is:






SPAM!!


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## ISeeDeadBTUs (May 8, 2008)

SPAM's too good a word for that sheetz! I hope the poor bass turd that started this thread didn't put a GW indoors! I 80% like my GW100, but I would NOT want it inside :bug:


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## deerefanatic (May 9, 2008)

I wouldn't want one either place!


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## jcremin (Sep 11, 2008)

I came across this thread with a Google search.  I'm also looking for an indoor wood-fired hydronic heater and I'm wondering if anyone has anything else they can share.  A few people suggested Greenwood, but why do you say you wouldn't want one, deerefanatic?  I live in Siren, WI which is not far from you so my heating requirements are probably similar.  ISeeDeadBTUs, why do you say you wouldn't want one inside?

My main concern right now is how much one will cost.  I plan to have it in my garage and retrofit my current LP furnace with a heat exchanger.  The house should be fine around 100,000 BTU's, but I may want to use it to also replace my current LP water heater which is heating my garage slab.  The garage shouldn't need too much, so they might both be find on a 100k btu system, but I'll have to do more research to see if a larger system would be better.

Like Lemms said, I need it to be a unit that can be used indoors as my village won't allow an outdoor unit to be used.  I have a nice HUGE garage, and I can drive right inside with a few truckloads of wood at a time and keep it and the stove inside, so I'm hoping I can find something that will work well.  A used unit would be perfect for me  

Thanks in advance,
Joe


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## jdurant (Sep 12, 2008)

go to marathonheaterco.com and look at the logwood boiler. I have one  ycob36 It can burn coal or wood. It works excellent. I just bought the coil to heat my water tank. My unit is in my basement. I love it.


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## jcremin (Sep 12, 2008)

What did you pay for it if you don't mind me asking?


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