# Does anyone NOT like their Garn? How do you feel about your Garn?



## ThisWarmHouse (Dec 15, 2008)

Hi Everybody,

ThisWarmHouse became the Garn dealer for a good chunk of the Eastern USA earlier this year and we are continuing to expand. We have quite a few Garn customers already and so far every single one of them loves their Garn. What I want to know is if there is anyone who doesn't love their Garn. I'm being serious. There has to be someone out there who doesn't like their Garn right? It's just not possible that there is 100% customer satisfaction right? So please if any of you regret your Garn purchase please let me know. My goal from this is to find out what if any situations there are where I shouldn't recommend a Garn to someone as long as they have the money, space and desire to burn wood. We work with more than one manufacturer and my goal is to always provide the optimal system recommendations. 

Thanks,

Derrick
ThisWarmHouse
800-333-4729


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## brad068 (Dec 15, 2008)

This thread is pure blasphemy! ;-P 

 Although mine is home grown I just love it!  Its getting a workout right now.  Last night was -5F with a WC @-25*F. Tonight, -10 to -15*F.  
So far so good.


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## flyingcow (Dec 16, 2008)

I only needed about 100,000btu's of heat, garn wasn't small enough. But I may build on just to use up btu's :coolsmile: They look like a nice unit.


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## ThisWarmHouse (Dec 16, 2008)

flyingcow said:
			
		

> I only needed about 100,000btu's of heat, garn wasn't small enough. But I may build on just to use up btu's :coolsmile: They look like a nice unit.




Was it not small enough regarding size of the unit or are you saying not small enough regarding btu's? Because the Garn uses integrated BTU storage you can't have a Garn that's too big. In the (house size / Garn size) ratio as your house gets smaller and the Garn gets bigger you don't get overheating or unused BTU's. Instead you get longer run time off of the thermal storage and between burns. A person using 25,000 btu's and using a Garn WHS2000 only has to batch burn once every other day.


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## Jim K in PA (Dec 16, 2008)

Hey Derrick.  Good to see you posting here at the Hearth.com forums.  

The GARN is fantastic.  It performs as well or better than advertised.  We are less than two weeks into our life with the unit, but we can't imagine a better solution.  The only "complaint" I have is the lack of any real guidance from Dectra on configuring the system.  Of course, the Hearth.com crew here in The Boiler Room have provided countless hours to anyone willing to search, listen, learn, and ask questions.


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## flyingcow (Dec 16, 2008)

ThisWarmHouse said:
			
		

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kind of late now, but i was told that(by a dealer) that my house wasn't big enough. I was looking for about 100,000btu's. Just found a Innova and will be tying it with my storage. If i remember, i think the small garn was pretty close to my cost of what I'm getting.


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## ThisWarmHouse (Dec 16, 2008)

flyingcow said:
			
		

> ThisWarmHouse said:
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That's too bad man. Sounds like you would have had a great situation for a Garn. Hopefully we can educate more people in regards to how the Garn's btu's relate to their home's btu requirements!


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## ThisWarmHouse (Dec 16, 2008)

Jim K in PA said:
			
		

> Hey Derrick.  Good to see you posting here at the Hearth.com forums.
> 
> The GARN is fantastic.  It performs as well or better than advertised.  We are less than two weeks into our life with the unit, but we can't imagine a better solution.  The only "complaint" I have is the lack of any real guidance from Dectra on configuring the system.  Of course, the Hearth.com crew here in The Boiler Room have provided countless hours to anyone willing to search, listen, learn, and ask questions.





Hey Jim,

Glad to see you on this thread. I'm really looking forward to coming out eventually and shooting some professional footage at your place. I have really appreciated you documenting your Garn install process, it's been so helpful. Regarding Hearth.com you can expect to see me on here quite a bit now. I'm hoping to learn as much as I can from others and educate others in areas where I can.


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## webbie (Dec 16, 2008)

This thread is close to the line...of being considered commercial advertising. 
Please check the forum rules.....

Nothing wrong with education, but if someone does not like their Garn chances are there would be a thread about it here. Just search on Garn and start reading. A sampling of 4 people including some that that may have bought from the posting dealer does not represent an adequate sample.

And, yes, you are correct - 100% customer satisfaction is impossible unless the sales of an item are so low as for it to not show up.


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## ThisWarmHouse (Dec 16, 2008)

Webmaster said:
			
		

> This thread is close to the line...of being considered commercial advertising.
> Please check the forum rules.....
> 
> Nothing wrong with education, but if someone does not like their Garn chances are there would be a thread about it here. Just search on Garn and start reading. A sampling of 4 people including some that that may have bought from the posting dealer does not represent an adequate sample.
> ...






Sorry, not trying to advertise. I just thought this forum would be a great place to gather data on what people think of their Garns. I'm new to the forum and wanted to get some quick feedback. Is there something you would like me to edit in the thread to make it more appropriate in your opinion? 

Thanks man, just wanting to join the Hearth.com gang.


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## webbie (Dec 16, 2008)

No problems...it is fine, as is.

I just try to keep the line somewhere, because before you know it we'll have 100 threads posted by the makers or dealers of each stove....

Speaking of that, I just found out that Hearth.com is more popular than the State Gov. of California site (which features Arnold).

In fact, our of 20 million sites monitored by Quantcast, we are now about 6,000. Take the porn sites out and we are probably in the top 3,000.

That makes us in to top 1/10th of 1%.........by far.


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## jebatty (Dec 16, 2008)

By far, most buyers of expensive products "like" and are "satisfied" with their purchase, as to admit otherwise would be to admit they made a very expensive and serious mistake. An overt customer satisfaction survey of such a product sounds more like marketing than serious research to determine satisfaction. 

Such a survey also is very self-selective, as most buyers of expensive products also have done quite a bit of research to determine in advance whether the product they bought will meet their needs. Assuming good research by buyers, a customer satisfaction survey will produce "satisfied" by definition.

Such a survey also does little to inform or educate non-product users of the objective merits or faults of the product.

Certainly, the Administrator's call on this post meeting the forum rules as to commercialization is to be respected, cause "he the man."


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## ThisWarmHouse (Dec 16, 2008)

jebatty said:
			
		

> By far, most buyers of expensive products "like" and are "satisfied" with their purchase, as to admit otherwise would be to admit they made a very expensive and serious mistake. An overt customer satisfaction survey of such a product sounds more like marketing than serious research to determine satisfaction.
> 
> Such a survey also is very self-selective, as most buyers of expensive products also have done quite a bit of research to determine in advance whether the product they bought will meet their needs. Assuming good research by buyers, a customer satisfaction survey will produce "satisfied" by definition.
> 
> ...






It's funny that you say that this does little to educate non-product users of the the faults of the product when that is exactly what I asked for. I already know situations where the Garn has worked well. I am looking for situations where it DOESN"T work well. I don't believe there is any one size fits all product and want to better educate myself and others on situations where the Garn isn't a good fit. As far as people who purchased a system not saying anything bad about it because they would have to admit they made a mistake is pretty bogus. Take a look around the forum bud, you don't have to look very far to find people who aren't happy and looking for help...

I definitely want to respect all forum rules and don't want hearth.com to become a marketing/advertising swarm either. That would totally kill the community. I'm on your team when it comes to that issue.


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## jebatty (Dec 16, 2008)

> Take a look around the forum bud ...



That's not my name.


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## topofthehil (Dec 16, 2008)

as far as the post of "The only “complaint” I have is the lack of any real guidance from Dectra on configuring the system.", martin also has a business that does just that.
for a price, he can design a system.
to do it right is time consuming.


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## ThisWarmHouse (Dec 16, 2008)

topofthehil said:
			
		

> as far as the post of "The only “complaint” I have is the lack of any real guidance from Dectra on configuring the system.", martin also has a business that does just that.
> for a price, he can design a system.
> to do it right is time consuming.




What type of configuration information? Is it the type of info that could be standardized or do you mean install specific info?


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## Eric Johnson (Dec 16, 2008)

Whatever happened to the member earlier this year who got the Garn delivered, but then couldn't afford to install it? I felt bad for the guy, but was surprised that he got that far without checking into some real-world numbers for the install.


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## sdrobertson (Dec 16, 2008)

Eric Johnson said:
			
		

> Whatever happened to the member earlier this year who got the Garn delivered, but then couldn't afford to install it? I felt bad for the guy, but was surprised that he got that far without checking into some real-world numbers for the install.



Wasn't he the gentlemen from way up in the mountains in Colorado?  You right and I had forgotten about him, Hopefully he got it hooked up by himself.


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## Jim K in PA (Dec 16, 2008)

topofthehil said:
			
		

> as far as the post of "The only “complaint” I have is the lack of any real guidance from Dectra on configuring the system.", martin also has a business that does just that.
> for a price, he can design a system.
> to do it right is time consuming.



toth - I am aware of and respect the fact that Dectra is also an engineering consulting firm.  I also own and manage an engineering consulting firm, and deal daily with potential "clients" fishing for freebie input.  However, with respect to the GARN 1500 and 2000 models, they could offer the "average" or "typical" buyer some more input as part of the $13,000-15,000+ cost of the units.  Given that the two units I mention are the ones that are most appropriate for, and primarily marketed to, single family homeowners, this offers the opportunity develop baseline system configurations that could then be adapted or modified to accomodate particular issues with each system.  That design adaptation or modifcation can be developed by the buyer or bought from Dectra (assuming you can get in touch with them).   how time consuming that effort is obviously depends on the scope of deviation from the "tpyical" application.  Having designed and implemented my system, I do not see how much more time would be necessary to implement something similar for another system, excepting mechanical constraints.  The very simple line schematics included in the August 2008 edition of the install manual I have are of no real use to a buyer that does not have experience in hydronics or access to such experience.  I also am fairly confident that very few P&H;contractors will have the level of experience in a heat and store system like the GARN to design an appropriate system.

Obviously this is just one perspective from one individual who has gone through the process of research, selection, purchase, design and installation of a GARN WHS2000 over the last 6 months.  I am not "faulting" Dectra over this issue, just offering a suggestion to the original poster and anyone else who may come across this post while doing their research into a GARN.  I have no regrets.


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## Eric Johnson (Dec 16, 2008)

sdrobertson said:
			
		

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That's the guy. Nice guy, too, as I recall. I hope he got it hooked up, but if he did, I doubt he did it himself, otherwise he would have been on here with all sorts of questions.


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## topofthehil (Dec 16, 2008)

Jim k in PA,
you are correct in respect to Garn not being as helpful as they could be with simple questions on installation and set up.
I knew/know little about install and design of a system and found that getting this information from Garn was very slow.
I think they need more tech people. hopefully they monitor their web site and step in to help answer questions.
however, to give martin credit where credit is due, when I had a fan problem, he was very fast to correct the problem.


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## Eric Johnson (Dec 16, 2008)

Derrick,

What sort of technical assistance do you guys provide, if any, when somebody buys a boiler from you? Do you do system design and engineering for a fee? Do you give estimates of what a customer can expect to spend on installation? If so, do you provide that information if the customer doesn't ask for it?

Those last two questions are getting back to the guy who had his boiler delivered and then balked at the installation cost. I'm mystified at how far he got into the process without that rather important information.


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## ThisWarmHouse (Dec 16, 2008)

Eric Johnson said:
			
		

> Derrick,
> 
> What sort of technical assistance do you guys provide, if any, when somebody buys a boiler from you? Do you do system design and engineering for a fee? Do you give estimates of what a customer can expect to spend on installation? If so, do you provide that information if the customer doesn't ask for it?
> 
> Those last two questions are getting back to the guy who had his boiler delivered and then balked at the installation cost. I'm mystified at how far he got into the process without that rather important information.





I want to be careful not do any type of advertising so I don't want to talk about our company specifically except if you want to PM me.

I think that when you buy a boiler basic system design regarding pump and pipe sizing for proper system flow and protection and pricing on all of the major components should be part of the selling process. What are you doing as a dealer if all you do is take money from the person? The manufacturer could do that themselves just as well. Someone buying a boiler system needs to be able to see all of the costs before they pull the trigger on the boiler itself. I feel bad for the guy with the Garn and no money to install. Don't know who dropped the ball on that one. 

Thanks for this type of feedback guys. 

Could some of you guys looking for Garn to give better setup and design info give some specifics of what you are looking for so that maybe we can push Dectra to step up their game in that department?


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## Eric Johnson (Dec 16, 2008)

Fair enough. Good response. Thanks.

When we started the Boiler Room about one year ago, we only had one actual Garn owner, Tom Caldwell, and a bunch of wannaGarns. Now they're gottaGarns, and their information and observations have really been a good addition to the site.


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## Sawyer (Dec 16, 2008)

Garnification said:
			
		

> This thread is pure blasphemy! ;-P
> 
> Although mine is home grown I just love it!  Its getting a workout right now.  Last night was -5F with a WC @-25*F. Tonight, -10 to -15*F.
> So far so good.



Oh, so the heat wave is south of us!


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## Eric Johnson (Dec 16, 2008)

I should have mentioned Garnification, who built his own, impressive-looking Garn-style boiler and has been very helpful and supportive of those interested in getting one of their own.


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## brad068 (Dec 17, 2008)

Sawyer said:
			
		

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Oh, I forgot about you northerners. Do you guys even turn your clocks back up there!?  

Did you guys see that in the upper poll there is one voter that HATES his Garn!?! Must be a communist. After all they do like their crude cold war downdrafters. :red:


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## Eric Johnson (Dec 17, 2008)

^^^^Except he has a nasty habit of knocking the Euro downdraft gasifiers.


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## Sawyer (Dec 17, 2008)

Garnification said:
			
		

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Clocks? Googled it, by Wikipedia's definition why would someone want one of those ;-)

As for the other, definitely KGB!


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## Tattooz (Dec 18, 2008)

Hate it....... Yup Hate it......
Hate that I didnt think of this 20 years ago.......
GARNS RULE  <----- sorry is that a breach????

STOKE IT........


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## mike1234 (Dec 18, 2008)

I know this could be a highly volatile question, but be gentle, it's just a question.  
Reading this commercial, er I mean thread, I just have to ask, how can a boiler that cost at least (as far as I have been able to tell from your posts) 15,000 to buy and install, (add 15,000 more if you have to build the shed) be something that saves you money?  Even if you use less wood than I do by 1/2, it would take about 8 years to pay it off.   Let say I pay my wood furnace off in 2, then I am pocketing that money, or buying a cool new chain saw, or a new splitter, or ..., for the 6 years you are still paying off the garn.  

I do understand that you might just prefer the boiler over the furnace as a preference.  But do you all have the $$ worked out so that what I said above is not the case?  Again be gentle, it's just a question, and I am not questioning your religious beliefs.


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## brad068 (Dec 18, 2008)

mike1234 said:
			
		

> I know this could be a highly volatile question, but be gentle, it's just a question.
> Reading this commercial, er I mean thread, I just have to ask, how can a boiler that cost at least (as far as I have been able to tell from your posts) 15,000 to buy and install, (add 15,000 more if you have to build the shed) be something that saves you money? Even if you use less wood than I do by 1/2, it would take about 8 years to pay it off. Let say I pay my wood furnace off in 2, then I am pocketing that money, or buying a cool new chain saw, or a new splitter, or ..., for the 6 years you are still paying off the garn.
> 
> I do understand that you might just prefer the boiler over the furnace as a preference. But do you all have the $$ worked out so that what I said above is not the case? Again be gentle, it's just a question, and I am not questioning your religious beliefs.



Alright ,we are going to compare apples toooo... watermelons. Can or are you heating your potable water? Can you heat multiple structures with your furnace? Can you burn your furnace all year to heat potable water? Can you heat your swimming pool? Can you hook up a hot water solar system to your furnace? And does your super jack have at least a 20 year track record?

For the average guy that only needs to heat one small structure then yes a Garn is probably out of the question, but for the folks that need the btu's these units really show there worth.

I grew up in a home with a wood furnace and they do get the job done, but having the wood and smoke in the basement and waking up with pasty dry mouth is not something that I was looking forward to in my own home.

 Oh yeah, and I've heard from folks around here that it only cost 10% more to go first class %-P


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## brad068 (Dec 18, 2008)

I was just thinking, I wonder if the Yukon super jack is the same furnace that the original super jacks were made by, Jackline. Some of them were little boilers like a horseshoe shape water jacket on top. They were hard to control the heat output and boiled over easy. They were built years ago just north of me and there was another line call Feldon Walker I think. Alot of folks around here had them and then they sold out probably to Yukon.


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## mike1234 (Dec 18, 2008)

OK, so if you are heating a home & detached shed and pool and .... then the furnace wouldn't even be an option.  Good point.
I like your apple to watermelon comparison, mine does look like an apple next to your watermelon.  
Mine does preheat hot water if I decided to put that option in, but only during the winter, and it's in the garage, no smoke smell in the house.   

BTW I also know that we all invested a certain $$ in our systems, so we will defend our choices to the last dollar.  I am not trying to convince you of anything, just enjoying the conversation.

Not sure about the Yukon history, but no horseshoe shaped thing at the top anymore.


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## Rick Stanley (Dec 18, 2008)

First of all, if I didn't have a lifetime supply of free wood, I wouldn't burn wood at all.

 Further, if I didn't have an existing building to put it into and if I didn't have future plans to heat multiple buildings (drafty old farmhouse with apartment/future apartment in other buildings/greenhouses/future slaughterhouse/food processing facility................a Garn is the last thing I would have bought. Quite honestly, if H. S. Tarm had a bigger unit I'd have gone that route.

I can burn 1800 gallons of oil a year right here in the house. Depending on the price of oil, the pay back on any boiler would be quite short, especially $4 oil. So, I'd say that Nofossil has the right idea, get the smallest rig that will work for your needs, hook it up right and run it right. Garn is a commercial rig in my opinion.


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## heaterman (Dec 18, 2008)

Just an FYI. I know for a fact that the folks at Dectra are seriously contemplating a unit sized for smaller applications. When that may happen is anyone's guess. I would not hold my breath for a couple reasons. Number one is that they are busier than a cat in a dog pound right now. Number two is that while the price point will be lower, I doubt that it will be a lot lower. The only savings in a smaller unit would be from the cost of steel, fabrication and labor would be nearly identical assuming the same design is used and I sure don't want them to mess with that.


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## jebatty (Dec 18, 2008)

The Garn website gives good general advice: "It is important to not undersize or oversize any heating appliance." That advice also comes from many forum participants. I will state my conclusion up front.

Conclusion: The Garn is an impressive wood boiler system which should perform very well when used with a heating load matching its design capabilities. Based on 350,000 BTU burn rate of the smallest Garn unit, it is probable that the Garn is not the best suited for average home heating needs. The average Minnesota home uses between 80-100 million BTU's/yr for heating.* Using 90 million for purposes of example, and assuming 8 months of heating, that works out to 350,000 BTU's/day. I don't know what the Garn efficiency is in transferring burn rate to actual water heated. Assuming 100% (which is not realistic), 64 minutes of burn time would meet the needs of the average Minnesota home on an average day. My system is rated at 140,000 BTU's. Assuming again 100% efficiency (not realistic), 2.5 hours of burn time would meet the similar need. Realistically, it probably would be appropriate to double both of these burn times to approach actual system performance.

This example highlights the advice to size a system appropriately, as it would appear that a sizable investment on a system to be used about two hours per day, when I am sure the design capacity is for much greater use, would not approach the return on investment for which the system is designed.

* http://www.state.mn.us/mn/externalDocs/Commerce/Home_Heating_110802040719_Heating.pdf

Discussion:

It's really difficult for any person, including Garn owners, to make a good evaluation, unless the person also has direct equivalent experience with other wood boiler systems, including OWB, gasification, etc. That means a side-by-side comparison of the various boilers for Heating System X, for example. If the heating systems are different, the outcomes would be different. My comments are based on Garn published specs for its smallest unit (to make the comparison as closely equivalent as possible to what I now have) + actual experience with the system I purchased and installed.

Garn was one of the boiler systems I considered before buying another boiler. I was impressed with the integral water storage, but for my application, even the smallest Garn appeared to be oversized, it physically took up too much space (turned out to be not very relevant after I added storage to the system I bought), and it was too heavy for me to handle with the equipment I had available. Initial purchase price and shipping also were out of the range that I was willing to spend.

Smallest Garn Unit (WHS 1500)
Physical size: roughly comparable to what I have when 1000 gallon LP storage tank is included in my system.

Empty weight: very close to what I have, including weight of 1000 gallon tank. I am able to handle my system with my own equipment (1000 lbs boiler + approx 2000 lbs tank), but I cannot handle a single 3500 lb appliance.

Firebox: Garn is much larger, and assuming equal quality of wood and equal efficiency of burns, Garn would provide a much longer burn time over what I have; would allow probably for one long, single burn rather than needing to refuel my system under certain circumstances. Ability to burn larger pieces in the Garn is an advantage as it reduces splitting and cutting time. I have seen posts that indicated the Garn can burn higher moisture content wood than the gasifiers should burn. I do not regard this as much of an advantage, if any, for the Garn, as burning increased moisture content wood increases burn inefficiency, potential of creosote formation, and increased smoke, particulate, and aromatic emissions. Future environmental regulations need to be considered if the intent is to burn high moisture content wood.

Ease of Cleaning/Maintenance: no experience with the Garn and no knowledge. My system is easy and quick to clean; maintenance I know of so far is annual on system shutdown for summer (about 2 hours time).

Storage: Garn has 1420 and my system has 1055. This is neither an advantage nor a disadvantage, as I could increase my storage to whatever I desired consistent with the capacity of my boiler. I believe my boiler easily could heat 1500 gallons of storage to maximum temp based on how easy it is to heat the 1000 gallons I have.

BTU burn rate: Garn is 350,000 and mine is 140,000. Each has its +'s and -'s. Garn would bring system up to full temp faster and continue to meet the demands of a much larger heat load than my system would do with equivalent storage. Based on my system's actual capacity to more than meet my heat load needs, my early-on conclusion that the Garn was more boiler than I needed was accurate. I think what is important is to size the boiler to the heat load needed; otherwise, if the boiler is oversized, burn inefficiencies most likely will result; and if undersized, heat needs will not be met.

Pressurized/Unpressurized: Garn is unpressurized and my system is pressurized. I initially installed my system with a pressurized boiler, hx, and unpressurized storage; since replaced with pressurized storage and system in total. This is a difficult one to state any specific conclusions, as each type of system has advantages and disadvantage. I believe that the Garn integrated open storage system should function very well, and it can be mated to a pressurized heat load with a heat exchanger. A pressurized system in total eliminates the need for the heat exchanger for space heating needs and pretty much eliminates the need to monitor water chemistry after the water is initially treated. I assume the Garn needs periodic water chemistry treatment, much as my old OWB required. This was relatively easy and the chemicals (150 gal open system) were not very expensive, but it was one more maintenance step required.

Quality: Garn has been around for a long time, as has the manufacturer of my system. I assume both to be of very high quality.

Support: Based on comments of others, Garn could do better in this area; the manufacturer of my system has received very high user marks on customer support.


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## ThisWarmHouse (Dec 18, 2008)

jbatty,

Great post. I have personally been trying to think down through some of these same comparisons. Especially regarding a completely pressurized system like the Tarm or Eko with a pressurized storage tank vs. the Garn with the integrated open unpressurized storage. I currently rent but plan to build in the next couple of years and part of my home design will be built around either using a Garn or a system like the Tarm. The thing that attracts me to the Garn is the simplicity. There is so little to go wrong yet it works so well. I don't want to write off alternatives.

I have a few questions I would love some feedback on.

1. The Garn's water needs to be periodically tested/treated and a pressurized system doesn't need to be. If you are faithful in testing and treating the Garn's water does either system have an advantage regarding longevity due to the pressurized vs. open system? Are open systems only more susceptible to corrosion when they aren't properly maintained? Why do the Garn open systems seem to last so much longer than other open systems I've seen?

2. Do the Tarm/Eko systems blow some smoke in your face when you open the door? One of the things I like about the Garn is the way the blower system is designed to not allow the smoke and flames to come out of the door when you open it. I have never experienced a Tarm/Eko system yet. Feedback?

3. With a Tarm/Eko system with a pressurized storage tank which is likely to go bad first, the storage or the boiler? What is a typical lifespan of one of these systems? I've heard of lots of 20+ year Garns on the field working great. I've heard the Tarms are long lasting but I don't know many specifics.

4. Are there any major efficiency differences between a Garn and a Tarm type system? 

5. I plan on building a monolithic dome home (super efficient) so I will have really low BTU requirements but with well insulated BTU storage I'm not really concerned with oversizing, in my mind it just means shorter and less frequent burns. Am I incorrect in that thinking? Or are there negatives I should be considering?


Anyone here had hands on experience with both? What are you impressions of both types of systems? Plus and negatives for each please.


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## Jim K in PA (Dec 18, 2008)

Mike - good questions, and if any GARN owners are actually offended by them, then they really did NOT do their homework, and may in fact have made the wrong decision to go with a GARN.  With respect to your payback question only, we need to compare apples:apples, along the lines of what Garnification was getting at.  Compared to an OWB, the GARN is significantly more expensive in initial cost for the unit, probably close to 75% more.  However, that is not an appropriate comparison, IMO.  Compared to gassification type stoves, the GARN is also more expensive, probably 40-50% more.  However, that does not address the difference in heat storage capacity.  Adding in the heat storage tanks and tranfer infrastructure, I think the GARN cost difference will be more in the 15-20% range.  I have not done an extensive comparison since my early research, but based on others descriptions of their gassifier+remote storage setups, I think the price differences I describe are fairly close.  However, if you must build an entirely new structure that you would NOT otherwise have had to build, that will obviously add more to the total cost.  I think your $15k estimate for the cost of the remote building is rather high, since the GARN itself does not need much more than an 8'x16' shed.  I think $1500-$2500 additional cost to house the GARN is a reasonable minimum number to add to the analysis.

So, Payback?  As with ANY option, that will be purely an arithmetic exercise.  Total the cost of the unit, total the annual cost savings of whatever fuel you are no longer burning, add the annual cost of the wood, and divide the total cost by the total annunal savings minus the annual wood cost, and you have your payback period.  For OUR economic calculations, based on $4/gallon oil price as of June 2008, and a 1240 gallon/year oil useage for our house alone, we were looking at a payback period of right around 4 years for our GARN.  Of course, that equation is out the window with oil now down in the $2/gallon price range again, so that payback period has now doubled.  However, we had to make a tough economic decision at the time of peak oil prices, without the ability to forsee whether prices were going up or down.

Jim - excellent points, as always.  I think the most interesting part of the GARN evaluation process is one of configuration.  The physical size and weight of the unit can be, and often is, THE determining factor in it's suitability for a particular application.  One would think that form factor would be a secondary consideration after efficiency and operation, but the GARN is an exceptionally large machine.

With respect to appropriateness to demand, the heat and store system is really the ideal configuration, regardless of what brand combustion unit you choose.  Storage capacity solves many issues that apparently are of significant consideration to non-storage equipped gassifier owners, specifically overheating and ability to meet demand over long periods of time without firing.  I think that when determine their heat needs and the size and storage capacity of their system, if the GARN exceeds this they discount it as an option.  While this is logical, to some extent it eliminates a perfectly viable option.  More storage capacity increases time between burns, and higher specific output decreases the time needed to re-charge the tank.  What I marvel at is how I quickly can recharge the storage while still meeting my heat load simultaneously.

I do agree that the GARN is technically and logistically more compatible with a multiple district (building) heat load due to it's size and output capacity.  That was one of the key factors in our decision to go with the GARN as I wanted to heat two outbuildings in addition to our house.  Forward planning was key to our decision process.

However, if I lived in a smaller home, with no plans for multiple building heat loads, I would likely have built a small outdoor structure to house a smaller gassifier, and incorporate storage in my house/basement.  While the cost would be a little less, that configuration would allow for some flexibility in the installation.

Good points here in this thread - I hope future wood furnace researchers come across it.


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## tigermaple (Dec 18, 2008)

The way I figure it the smallest Garn would cost 6-8 grand more than my GW100 installed.  That is 40 cords of wood in todays market.  More than 4 years of fuel for me plus the wood needs splitting.  How much less if any would I burn with a Garn over that 4 years?  
Jeez,  20 grand could get you a GW100 and a 5 acre woodlot plus you could let the wood grow for 4 years adding 30% wood mass.


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## jebatty (Dec 18, 2008)

> If you are faithful in testing and treating the Garn’s water does either system have an advantage regarding longevity due to the pressurized vs. open system? Are open systems only more susceptible to corrosion when they aren’t properly maintained? Why do the Garn open systems seem to last so much longer than other open systems I’ve seen?



Under the conditions you state, I know of no reason why either type of system would have a material longevity benefit. Everything else being equal, I believe pH maintenance and keeping O2 out of the water are the prime considerations with either system. Acid and oxygen are steel corrosion hogs. Without knowing more about the other open systems you mention, I really can't respond. The only other factor that comes readily to mind is the quality of steel, welds, and construction, all of which also would relate to longevity.



> Do the Tarm/Eko systems blow some smoke in your face when you open the door?



As to the Tarm, yes and no. If I follow Tarm's instructions and only open the firebox door after the fuel load has burned down to low coals, then I think I safely can say "no smoke." But often this is not convenient, and I frequently top off the firebox while a burn still is in process. If I'm careful here, I can almost always eliminate smoke of any consequence. But if I'm a little careless, I will get some smoke. For some people, any smoke is too much smoke. It's of no consequence for me.



> With a Tarm/Eko system with a pressurized storage tank which is likely to go bad first, the storage or the boiler? What is a typical lifespan of one of these systems? I’ve heard of lots of 20+ year Garns on the field working great. I’ve heard the Tarms are long lasting but I don’t know many specifics.



There may be many variable at work here. My assumption is that my storage tank, a used LP tank, is of high quality steel, and I see no reason why it should not last for a very long time. Tarm provides a 20 year boiler body warranty, amortized. I'm only in my second season of operation, and all I can say is that so far, it's still "alive."



> Are there any major efficiency differences between a Garn and a Tarm type system?



Based on manufacturer published data, they appear to be of approximately equal efficiencies. Both seem to have combustion efficiency of 97% or more. Tarm advertises overall efficiency of 75-80%. I have not seen published overall efficiency data for Garn. There may be some engineering differences between them which lead to (assumed small) efficiency differences.



> [will have low BTU requirements]...in my mind it [Garn] just means shorter and less frequent burns. Am I incorrect in that thinking? Or are there negatives I should be considering?



If you are contemplating buying a wood heating appliance (Garn, Tarm, Eko, etc.) grossly over-rated for your heat load requirements, I think you are spending excess money and your cost/benefit ration will decline. I think the ideal system is one which is firing 100% of the time and modulated to meet a varying heat load demand. Since this is not available for wood, you will be firing the boiler, letting it burn out, and repeating. Each firing has a start-up component when it is burning wood to come up to operating temperature. This is the most inefficient period of the burn. Ideally you would like to minimize these situations, as each is wasting wood heat energy.

Whether shorter, less frequent burns, will meet your needs depends on how hot you need your water. An in-floor radiant system can operate on a much lower heat of water than will a baseboard system. If you need 160 water, then you will have more frequent burns than if you only need 120 water.

There is another factor which I think may be relevant. Long periods which allow the firebox to cool so as to permit possible condensation in the firebox should be avoided, as condensation in the firebox plus creosote on the firebox walls = acid = corrosion. So long as the firebox is kept warm enough (by surrounding water in the boiler or otherwise) to prevent condensation, this should not be a problem.


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## brad068 (Dec 18, 2008)

I got to throw in my other 2 cents. 1, the garn unit aren't as affected by a power outage as some of the dd's are. You don't need a mixing valve to get the correct return temp, or another circ to remove the heat to storage, and you don't need a overtemp dump or plumb it to siphon heat- simple is better!

2, these units are so simple. If you break the firebrick you don't need it special from Denmark or Czechoslovakia. you can go downtown and get new ones same with the motor, Graingers,msc,etc. Secondary chamber I can make that myself and I have found a place too. Only think left is the timer, same places. The units have but one door and the majority of the unit and its guts are round- equal expansion few joints= long life

3, ayuh,.. found a penny. I timed myself the other day and I beat my old record of 6 minutes, did it in 5 3/4's Thats the time it takes me to walk in the door, load, start a fire ( I forgot to tell garn folks this, use cardboard to start your fires works the best), go fill the wheelbarrow and bring it back, check the fire then exit.

Another! penny... I 've seen a tarm unit in action and I got to say the firebox is small. Think it was a solo 60 or something. My fingers would be all brusied up if I had to put wood in a door that small. But then again your throwing in twigs (not leaving anything for the birds to make nesting out of). I do split up my wood but not that small and it seems to burn it just fine.


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## jebatty (Dec 19, 2008)

Correct statement that Garn takes larger wood pieces than, for example, Tarm. The Tarm is designed essentially to burn small splits (4-5" diameter) up to 20" long (18" works better). There will be more splitting and cutting with a Tarm than with Garn. I did mention this in my first long post above.


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## sdrobertson (Dec 19, 2008)

I haven't gotten in on this one yet so here I go - I enjoy trying to build something with my own hands and I like to scrounge things to try and do my work as cheap as possible so I can spend the rest of my money on the kids. This being said, I'll buy new most of the time as I'm limited on my scroungeing time. I went with the EKO because: 1. It was "used" but never fired so a deal. 2. I had access to propane tanks for storage. 3. My father has one and I new the quality. 4. I read about but had never actually seen a Garn. 5. Others but minor.

I have roughly $7000.00 into my system and even though I haven't priced it I'm guessing that's over half of a GARN. This doesn't include the pole building or insulation as I would need both for either unit. I would never direct anyone to not purchase a GARN as I see absolutely no down side to them. They are a beautiful boiler and I would love to own one as they are incredible simple and efficient. I own a S-10 4x4 but would love a diesel one ton 4 door 4x4 long bed(w/plow).


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## heaterman (Dec 19, 2008)

I want to hear from the guy who voted that he hates his Garn. What in particular is the problem?


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## BrownianHeatingTech (Dec 19, 2008)

ThisWarmHouse said:
			
		

> 1. The Garn's water needs to be periodically tested/treated and a pressurized system doesn't need to be. If you are faithful in testing and treating the Garn's water does either system have an advantage regarding longevity due to the pressurized vs. open system? Are open systems only more susceptible to corrosion when they aren't properly maintained? Why do the Garn open systems seem to last so much longer than other open systems I've seen?



Properly-maintained, either system should last decades.

Garns tend to last longer than other open systems (eg, outdoor wood boilers) primarily because folks actually maintain the water quality.  Many OWB's see little if any water treatment.

That said, I am aware of some Garns leaking due to bad water, so proper treatment really must be followed.  That could be seen as a disadvantage, although even closed systems should have their water monitored (they are just less likely to have problems).



			
				ThisWarmHouse said:
			
		

> 2. Do the Tarm/Eko systems blow some smoke in your face when you open the door? One of the things I like about the Garn is the way the blower system is designed to not allow the smoke and flames to come out of the door when you open it. I have never experienced a Tarm/Eko system yet. Feedback?



The Eko and the Tarm/Scandtec Solo Plus series can release smoke.  The Tarm Solo Innova and the Fröling are both induced-draft like the Garn, and include smoke extraction passages, so smoke release is similar to or less than what you would see with a Garn.



			
				ThisWarmHouse said:
			
		

> 3. With a Tarm/Eko system with a pressurized storage tank which is likely to go bad first, the storage or the boiler? What is a typical lifespan of one of these systems? I've heard of lots of 20+ year Garns on the field working great. I've heard the Tarms are long lasting but I don't know many specifics.



Depends upon the tanks that are used.  Folks building systems using salvaged tanks (propane or other) may be taking a gamble with what the condition of the tank actually is.  I've even heard of folks using used fuel oil tanks for pressurized storage - which is certainly do-able, but I think it's safe to say that such tanks will fail much sooner than the boiler, in most cases.

The tanks that Tarm sells are ASME-rated pressure vessels, designed to handle pressures (125PSI, if I recall correctly) far in excess of what we use in typical heating systems.  They are actually expansion tanks designed for commercial systems, so they are designed to operate with water and air in them, creating a corrosive environment, and still provide reasonable longevity.  So it's safe to say that they are made of some very thick, high quality steel, and will last many decades in normal use.  I don't even install isolation valves on them, because the odds of a tank failing are trivially-low, and I'd say that the valve is more likely to fail than the tank.



			
				ThisWarmHouse said:
			
		

> 4. Are there any major efficiency differences between a Garn and a Tarm type system?



I believe that Garn lists an efficiency on the order of 75%.  The Tarm/Scandtec Solo Plus series generally provides an efficiency on the order of 80%, the Tarm Solo Innova should be around 85%, and the Fröling provides a rated efficiency in excess of 90%.

So, the Garn is the lowest among those, in combustion efficiency (presuming that the others are all installed with storage, to be comparable).  Of course, none of the other units being discussed are in the same output class as the Garn units, so it's really an apples to oranges comparison - most boilers in the same size range as the Garn will post similar numbers.



			
				ThisWarmHouse said:
			
		

> 5. I plan on building a monolithic dome home (super efficient) so I will have really low BTU requirements but with well insulated BTU storage I'm not really concerned with oversizing, in my mind it just means shorter and less frequent burns. Am I incorrect in that thinking? Or are there negatives I should be considering?



First step in sizing is to determine the heat load (peak and average) of your structure, and to decide how long you want to go between burns (during peak and average conditions).  Then design the radiation in order to determine the minimum water temp which will allow proper operation.  Use that number, or 120-degrees (whichever is higher), and determine how many gallons of water you need in order to supply the given load for the given between-burn interval.

Once you know how large a tank you need, then you can see what system will be appropriate.  If you figure that you need 600 gallons, then even a WHS1500 might be a wee bit excessive.  If you need 1200 gallons, jumping up to a WHS1500 might not be that crazy.

Assuming that you are sizing a separate tank and boiler, you size the tank to the above conditions, then size the boiler based upon realistic tank re-heating.  The boiler size in a storage situation is not related to the heat load - it is related to the tank size.



			
				ThisWarmHouse said:
			
		

> Anyone here had hands on experience with both? What are you impressions of both types of systems? Plus and negatives for each please.



I don't have direct experience with Garns yet (ie, I have never installed one), but they have a good reputation.  I wouldn't hesitate to specify one for an appropriate situation, although I should put a caveat on there that I really only think there is much use for the WHS2000 - below that, I would likely specify a Tarm- or Fröling-based coupled with appropriate storage tanks (possibly sourced from Dectra if on the large side, since they do supply bare tanks without the boiler guts).  It's in the 2000-gallon and larger systems where I think the Garn really has its niche.

Joe


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## jklingel (Dec 19, 2008)

WarmHouse: I don't see your post as commercial at all. Anyone brave enough to ask to (potentially) be ripped to pieces publicly should be commended. I've read all the responses, and some very good points were brought up, so I am glad this thread exists. I am looking real hard at a Garn, and don't feel the "physically too big" is a valid point if a person is going to add a storage tank to his/her smaller boiler. Two separate items eat up a lot of floor space and pipes/valves.... I can't yet comment on the "over-size is fine, it just means fewer firings" because I don't have a wood boiler yet, and that is one issue I have wondered about. As I see it, most boilers in most situations should have storage, so you either have it in your boiler or next to it. I did ask the new Garn dealer up here if a slightly smaller Garn was perhaps in the works, but I have not as yet heard back. My gut feeling is to want a boiler just a tad smaller than the Garn 1500, but that is only a gut. As for cost, I have not priced a Garn yet, but an Econoburn (I think it was) will cost me $12K and a Tarm about $10K. Add storage and plumbing, and that will probably be relatively close to a Garn; no? Dunno. So, you guys keep firing away and I'll keep reading. Thanks for the thoughts.


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## jebatty (Dec 19, 2008)

Joe - a major difference between your input and some by others, including myself, is your experience in the field. I always read your comments with interest.



> The boiler size in a storage situation is not related to the heat load - it is related to the tank size.



This point is pure logic and I need to remember it. The caveat is the situation where the storage itself is undersized, which may occur for a variety of reasons, including space available.



> So, the Garn is the lowest among those, in combustion efficiency



You and I may be using different terminology but talking the same point. I understand combustion efficiency to be different from boiler efficiency. The first relates purely to combustion, and I think all of the gasification boilers are within 1% or so on this, ranging between 97-99%. The second relates to efficiency in transferring the combustion heat to the water (my use of the term "boiler efficiency"). I think this is what your efficiency numbers relate to.


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## mike1234 (Dec 19, 2008)

Let's talk about this 95 - 97% efficiency rating.  I have a 95% rated propane furnace, which has PVC intake and PVC exhaust.  5% of the heat is lost up the chimney, so PVC is appropriate.  I am fairly sure no wood burning appliance would say that PVC for the exhaust is OK, way too much heat goes up that chimney, in fact to keep the chimney clean it needs to be about 300 or so, right?
Given those facts, how can a wood boiler/furnace/insert/ anything be 95% efficient if that much heat is going up the chimney, and not into your home?  Just seems like these numbers are a little optimistic.  

I have learned a lot about boilers in this thread, if I had more than 1 building to heat, and if I had 15,000, and if I was a much better plumber than I am (I hate plumbing repairs, 1 repair leads to 4 more problems and repairs) then I think it would be better, yes I said better than my wood furnace.  1 building, no plumbing, in my situation I think the furnace was right for me.

If I was shopping right now for a method of wood heat, this thread would be more help then most of the research I did when I was shopping. (I didn't find hearth.com until after I purchased my furnace).

Someday, when I travel east and north of here, I'd sure like to see some of these boilers you have all installed in operation.


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## jebatty (Dec 19, 2008)

> Let’s talk about this 95 - 97% efficiency rating.



For gasification boilers, this is combustion efficiency, meaning this % of energy in the wood that is combusted (turned into heat). It is not the amount of heat combusted transferred to water. I assume your propane appliance is rated on heat generated transferred to your system. Do you have info on raw propane btu's actually combusted? 

Example for wood gasification boiler: 98% combustion efficiency x 80% heat transfer efficiency = 78% overall efficiency.


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## Floydian (Dec 19, 2008)

Howdy folks-
This site has been invaluable to me. I found it looking for info on wood stoves and now I'm  committed to wanting to go the gassifier route. 
I've spent many, many hours on here and really appreciate the knowledge-Thanks to All.
My situation is I'm looking for heat/DHW to  two houses approx. 385' apart. So I'm comparing two downdraft units+storage(one in each basement) VS.
a Garn+underground lines (sprayfoam in trench vs. prefab) +building.
I visited a Garn 1500 yesterday and was certainly impressed. I'm visiting someone with a Tarm at the end of this month and I'm hoping to see an
EKO in operation as well. These are some tough decisions but I'm enjoying the research. 
This has been a great thread and really shows how some things work for some people and don't for others.
I don't know what works for me. YET.

Just wanted to say hello and thanks.
Noah


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## ThisWarmHouse (Dec 19, 2008)

Just wanted to throw some info out there for the people asking about Garn efficiency. 

When calculating total system efficiency there are two numbers you are dealing with. Combustion efficiency and transfer efficiency. To get system efficiency you multiply combustion efficiency % by transfer efficiency %.

*Combustion efficiency* is a number that has been used and abused by those in OWB marketing especially. Some companies that really wanted to over rate their combustion efficiencies would weigh the wood they were burning and then burn the ash that was left over and figure out what % of the wood didn't burn. This is ridiculous as your wood is going to burn down to the same amount of ash in most situations. So these companies would burn wood with low ash content and say "We have 99% combustion efficiency". This method doesn't look at factors like how many BTUs are stored in the wood and how many of those BTUs are actually combusted so it totally ignores the potential for gasification ignoring the fact that 50 - 60% of your btu's are actually going up your chimney in the form of unburned gasses and smoke. So for combustion efficiency if a boiler is not gasifying it can not even have 50% combustion efficiency in reality.


*Transfer efficiency* is the percentage of heat that is combusted that actually makes it into your home/storage. If you are creating 100,000 btu's of heat in the firebox and gasification chamber but 20,000 btu's are going up the chimney than you have an 80% transfer efficiency. One misconception I had when I first got into this industry was thinking "why not just make a better heat exchange system and get the transfer efficiencies even higher. The problem with this is if you get your stack temperature too low (below 300) you can get condensation and corrosion problems. So there is a wall regarding how high transfer efficiency can be. This is why since most gasifiers have very similar combustion efficiencies and you can only get transfer efficiencies up only to a certain level it seems that most all of the popular gasifiers are in a very similar efficiency range. 


Looking at a traditional OWB that has a real world combustion efficiency of 50% and a transfer efficiency of around 50% (hot stack temps) you multiply the 2 numbers together and you find out that many typical OWB's actually have a total system efficiency of around 25%! 


The Garn has been tested by an outside laboratory and it has a total system efficiency of up to 84% (factors include wood type, moisture content and other burn practices). I'll have to get the individual combustion and transfer efficiencies for you. But the total system efficiency is the number that really matters anyways


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## Zick (Dec 19, 2008)

tigermaple said:
			
		

> The way I figure it the smallest Garn would cost 6-8 grand more than my GW100 installed.  That is 40 cords of wood in todays market.  More than 4 years of fuel for me plus the wood needs splitting.  How much less if any would I burn with a Garn over that 4 years?
> Jeez,  20 grand could get you a GW100 and a 5 acre woodlot plus you could let the wood grow for 4 years adding 30% wood mass.



This is/was my delema just recently since I have both a Greenwood and Garn dealer close to me.
I was originally going to go with a GW100 due to it's price and simplicity but found there are some disconcerning problems/complaints with the gw100's. 
Then I found the Garn WHS1500 and it looked perfect, simple to run/maintain, almost no complaints about and it's an all in one package but the price shocked the hell out of me.
But then I started pricing out what a gw100 with a storage tank (not home made) together would cost and found that the Garn was really not much more. Now granted you could make your own storage or not use one at all but you would be probably using more wood in the long run.


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## ThisWarmHouse (Dec 19, 2008)

Zick said:
			
		

> tigermaple said:
> 
> 
> 
> ...




I'm a Greenwood and Garn dealer so take this with a grain of salt. When looking for the best value don't just look at your upfront costs. You also have to look at the other end of the bookend. Longevity. If your Greenwood only lasts you 60% as long as a Garn is it still going to save you money in the end when you have to replace your system? I'm not saying that's going to be the case. It's just that Garn has the long track record with 25+ year old systems still running in the field and Greenwoods have only been on the market for 4 years. So we just don't know.


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## tigermaple (Dec 19, 2008)

Let me say I love the Garn concept and studied the " which boiler" problem intensely for several years before getting a gw100.  If there was a smaller Garn type I would have been all over it. I felt just heating something so massive to warm 3000sf was a waste to begin with. There are surely measurable heat losses in doing so.
As far as storage, I don't have any so I don't know what I'm missing. How much less wood would I burn with storage?


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## ThisWarmHouse (Dec 19, 2008)

tigermaple said:
			
		

> Let me say I love the Garn concept and studied the " which boiler" problem intensely for several years before getting a gw100.  If there was a smaller Garn type I would have been all over it. I felt just heating something so massive to warm 3000sf was a waste to begin with. There are surely measurable heat losses in doing so.
> As far as storage, I don't have any so I don't know what I'm missing. How much less wood would I burn with storage?



There are definately some situations where a Greenwood just fits better, that's the whole reason we sell both systems. Don't think that I'm saying the Garn is always the better choice. 

Regarding storage I think most Greenwood owners don't have extra storage. The benefit of the storage isn't just for efficiency and how much wood you would burn. It also effects time between burns, how much smoke you produce and also gives you an extra buffer to protect you against thermal spiking.


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## heaterman (Dec 19, 2008)

tigermaple said:
			
		

> Let me say I love the Garn concept and studied the " which boiler" problem intensely for several years before getting a gw100.  If there was a smaller Garn type I would have been all over it. I felt just heating something so massive to warm 3000sf was a waste to begin with. There are surely measurable heat losses in doing so.
> As far as storage, I don't have any so I don't know what I'm missing. How much less wood would I burn with storage?



Standby losses are definitely a factor when you are storing btu's in 1500-2000 gallons of water. The fact is though that these are easily dealt with by using your head during installation of underground piping and insulating the Garn itself. With a little planning, use of the appropriate materials and due diligence during the process, the standby losses can be brought to a point of being negligible.


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## Zick (Dec 19, 2008)

ThisWarmHouse said:
			
		

> Zick said:
> 
> 
> 
> ...



Yet another reason I'm leaning more toward a Garn. Sounds like they do last a long time with proper maintenance. I saw the one thread on here where the entire side of the GW was rusted through. Now that may have been operating error or manufacturer defect but it just didn't sit well with me. Also, I haven't been able to find out what happens if the refactory casting cracks enough where it falls apart. Does GW cover this under warrenty? I've heard that they will send you a mortor type patch but what if the casting is beyond patching and needs replacing?
We are building a new home this year and hope to be in it for at least 20 years.


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## Floydian (Dec 19, 2008)

"Standby losses are definitely a factor when you are storing btu's in 1500-2000 gallons of water. The fact is though that these are easily dealt with by using your head during installation of underground piping and insulating the Garn itself. With a little planning, use of the appropriate materials and due diligence during the process, the standby losses can be brought to a point of being negligible."

Heaterman,what would you consider negligible heat loss for underground piping? This is a big concern as my conversations with several retailers of 
the highest quality prefab options say I could see a loss of 1 or so  degrees over 200' @10 gpm. My calculations show that could be between around 120k btu's/day or more. Times that by 2 for 2 houses and thats a lot of loss IMO. I've seen better claims with sprayfoam in the trench but even at half of that is still adds up over a year.
Am I close with this math?

Any estimation  of heat loss for a Garn building thats the minimum size for the unit and  space around the door to load it comfortably, assuming its very well insulated?
These numbers could be huge in a situation like mine.

Thanks,
Noah


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## ThisWarmHouse (Dec 19, 2008)

Zick said:
			
		

> ThisWarmHouse said:
> 
> 
> 
> ...





Greenwood covers the refractory for the 10 year warranty. They don't cover surface cracks which are just cosmetic and don't affect the function of the unit, but if a piece cracks all the way through they will replace it. The newer multi-piece refractories they are making are much better than the old single piece ones they had. I've had bad experience trying to move used units with the old single piece refractory, they tend to collapse during transport. The new multi piece design doesn't seem to have those type of problems.


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## Zick (Dec 19, 2008)

ThisWarmHouse said:
			
		

> Greenwood covers the refractory for the 10 year warranty. They don't cover surface cracks which are just cosmetic and don't affect the function of the unit, but if a piece cracks all the way through they will replace it. The newer multi-piece refractories they are making are much better than the old single piece ones they had. I've had bad experience trying to move used units with the old single piece refractory, they tend to collapse during transport. The new multi piece design doesn't seem to have those type of problems.



Thanks ThisWarmHouse, I didn't realize they are now using multi piece design vs one single piece.


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## BrownianHeatingTech (Dec 19, 2008)

jebatty said:
			
		

> You and I may be using different terminology but talking the same point. I understand combustion efficiency to be different from boiler efficiency. The first relates purely to combustion, and I think all of the gasification boilers are within 1% or so on this, ranging between 97-99%. The second relates to efficiency in transferring the combustion heat to the water (my use of the term "boiler efficiency"). I think this is what your efficiency numbers relate to.



As I'm using it, "combustion efficiency" means the entire process, from wood in, to exhaust gasses and hot water leaving the boiler.

This is in contrast to "system efficiency," which includes standby losses, piping losses, etc. etc.

Combustion efficiency is the efficiency of the heat plant, itself, under full-burn operation.  System efficiency is energy (fuel) in, versus energy (heat) delivered to the living space.

We run across that difference quite often in fossil fuel systems.  An oil boiler with an internal coil ("tankless" or "warm start") may have the same 85% AFUE (combustion) efficiency as a similar boiler with an indirect water heater (ie, a "cold start" system) next to it.  However, the system efficiency of the first will be about 55%, while the system efficiency of the second will be about 65%.  The difference results from not keeping the boiler hot all summer just to produce domestic hot water.  The reason the system efficiency is still lower than the combustion efficiency is because of additional losses, like burning heated indoor air, using a significant amount of oil just to heat the iron block, before delivering heat to the house, etc.

System efficiency will always be lower than combustion efficiency.  How much lower can depend upon the design of the system pretty dramatically, even with identical boilers.

There are other factors, as well.  A Garn (or any boiler with storage) being used all summer for domestic hot water will have a lower system efficiency as a result of keeping that tank hot all summer.  However, by not using fossil fuels to produce domestic hot water, and using inexpensive wood instead, the lower efficiency really isn't that important.  Slightly lower efficiency utilization of an inexpensive, renewable fuel is going to beat higher-efficiency utilization of an expensive, non-renewable fuel, both economically and environmentally.

Joe


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## jebatty (Dec 19, 2008)

Regarding standby losses, I made this pretty much go away by installing the Tarm and the 1000 gal storage in a space to be heated anyway. All "standby losses" simply provide heat that otherwise would be drawn from the system.

I realize this is not possible for many, but do what you can, and if you are planning new home or building construction, allow for it. It represents a substantial gain in effective system efficiency.


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## BrownianHeatingTech (Dec 19, 2008)

jebatty said:
			
		

> Regarding standby losses, I made this pretty much go away by installing the Tarm and the 1000 gal storage in a space to be heated anyway. All "standby losses" simply provide heat that otherwise would be drawn from the system.
> 
> I realize this is not possible for many, but do what you can, and if you are planning new home or building construction, allow for it. It represents a substantial gain in effective system efficiency.



That applies during the heating season, but constitutes a loss when you don't need the heat there (ie, portions of spring, summer, portions of fall).

Joe


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## jebatty (Dec 19, 2008)

Agreed. I don't use my system for dhw, just space heating. My storage has removable insulation. I take some off during colder periods and put some back on when not much heat is needed. During Spring/Fall, I may fire the Tarm only once every 4-6 days; during this current cold spell (lows down to -20F and some highs not clearing 0), I fire 4-7 hrs/day.


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## heaterman (Dec 20, 2008)

Floydian said:
			
		

> "Standby losses are definitely a factor when you are storing btu's in 1500-2000 gallons of water. The fact is though that these are easily dealt with by using your head during installation of underground piping and insulating the Garn itself. With a little planning, use of the appropriate materials and due diligence during the process, the standby losses can be brought to a point of being negligible."
> 
> Heaterman,what would you consider negligible heat loss for underground piping? This is a big concern as my conversations with several retailers of
> the highest quality prefab options say I could see a loss of 1 or so  degrees over 200' @10 gpm. My calculations show that could be between around 120k btu's/day or more. Times that by 2 for 2 houses and thats a lot of loss IMO. I've seen better claims with sprayfoam in the trench but even at half of that is still adds up over a year.
> ...



Let me visit a couple job sites have been in in operation for a year or two and get I'll get back to you on that with some examples.


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## Floydian (Dec 22, 2008)

heaterman said:
			
		

> Floydian said:
> 
> 
> 
> ...



Thanks Heaterman, I'd appreciate that.
Noah


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## drpolc (Jan 6, 2009)

On GARN's longevity vs. other open-system boilers... I called GARN and they confirmed and enhanced my understanding.

1) All seams are welded inside and out. To do this you need access to all seams once unit is assembled. GARN has a manway... go see a GARN somewhere... likely they will let you crawl inside and see for yourself. This prevents crevice corrosion.

2) All steel is grit blasted (a more expensive process to get all the slag and microscopic crud - that can hid and encourage corrosion - off the steel).

3) GARN uses 3/16 and 1/4 inch steel.

4) GARN's water tank is rounded, not rectangular. This prevents sedimentation from sitting on welded seams which can facilitate corrosion over the long haul.

5) The bottom of every GARN is coated with epoxy. This prevents sedimentation from laying against the metal on the bottom of the tank.

6) Self sacrificing anode rods. Every GARN has these rods to detect any stray electrical currents that could accelerate metal corrosion.

7) Best of all... GARN has an effective and ongoing chemical treatment and analysis plan. Buy a GARN and with the chemical treatment you get 5 years of bi-annual testing. The treatment company will send you a kit to take a water sample every 6 months. You send it in to the company and they provide GARN and your local distributor with a complete water analysis with recommend remediation plan if needed.

Hope this helps


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## slowzuki (Jan 7, 2009)

Regarding some comments earlier related to space, I'm finding the clearances required for most boilers makes them take up a lot more space than you would think.  I'm assuming the garn can have items touching the water jacket and only needs clearance on the front where sparks may jump out while loading.


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## Jim K in PA (Jan 7, 2009)

slowzuki said:
			
		

> Regarding some comments earlier related to space, I'm finding the clearances required for most boilers makes them take up a lot more space than you would think.  I'm assuming the garn can have items touching the water jacket and only needs clearance on the front where sparks may jump out while loading.



GARN recommends about 2" clearance on the sides, about 18" at the rear (which you want anyway for access to the rear piping) and about 5' clearance at the front for safe loading.  I have less than that on the sides of mine.  I agree that the only places of real concern are the rear flue exit and the loading door.  The rest of the GARN is water jacket, so will not exceed the temperature of the water, and is actually less.  My WHS2000 is in a 6'x6'x12' space with a 10' shed at the door end for wood storage and loading.  I ran all my piping through the side wall into the garage where I have my primary loop.  See my setup in my link below.


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## Eric Johnson (Jan 7, 2009)

slowzuki said:
			
		

> Regarding some comments earlier related to space, I'm finding the clearances required for most boilers makes them take up a lot more space than you would think.  I'm assuming the garn can have items touching the water jacket and only needs clearance on the front where sparks may jump out while loading.



Like mine, Ken?


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## slowzuki (Jan 8, 2009)

Eric yours is nice and tight due to the masonry, I'm thinking in terms of plunking one down in a wood framed building.  Mine needs 24" on one side, 12" on the other, like 24" at the rear and a bunch at the front.  Then with the flue requirements added, I get a pretty big footprint.  With my storage tank being 5 ft in diameter and 10 ft long with no clearance, I really start to see the advantage of the Garn when you are going with storage.


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## Eric Johnson (Jan 8, 2009)

I started out with a wood-framed boiler room (with my old, conventional wood-fired boiler), but found it difficult to sleep at night. Concrete and steel was certainly worth the extra expense and effort. Luckily, the EKO 60 just fit, because I built the room for the old boiler. And I learned that I'm not much of a mason when it came time to fit the doors, but that's why they made caulk, right?


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