A Guy Who Obviously Believed the Hype

[Eric Johnson]

It depends on who you talk to. I think OWBs get scapegoated for a lot of pollution caused by woodstoves and other types of wood burners--both older units and newer ones being operated incorrectly. Or indoor boilers and furnaces, which are exempt from EPA regs. It's just they're not parked in the backyard where everyone can see them. One big problem with OWBs is one of their big selling points: You can burn anything in them....and people do.

But the facts are these:

Gasifiers burn about half as much wood for a comparable amount of heat;
They're two to three times as efficient as an OWB as a result;
They make no visible smoke or smell when operating.

BUT.....

They need very dry wood to work properly;
They cost more than most OWBs;
Setting them up right is more complex and expensive than a typical OWB installation;
They tend to go inside the house, which can have insurance implications

Some companies are making outdoor gasifiers which aren't cheap, but I think they work pretty well if you feed them dry wood.

So if efficiency, smoke and wood supply are not your big concerns, go with an OWB. If they are, then you should seriously consider a gasifier.

It's as simple as that in my book.

 

[jklingel]

Eric: Thanks for the clarification. Am researching like crazy. Tarm seems to have good quality, and Aqua-Therm will be bringing out a gasifier in the middle of '08, the Omega HE. I will keep reading, looking for others. j

 

[slowzuki]

I'll stick my nose in too, many of the outdoor boilers here are way oversized and end up sitting and smoking all day long stinking out neighbours.

 

[saichele]

I love that loading system. Load up about a face cord at a time...

Steve

 

[Eric Johnson]

Tarm makes a great gasifier, but it takes shorter wood (20") than the EKO which was a big consideration for me, since I have quite a bit stockpiled and it's all 24".

Maybe it's just because now that I have one I pay closer attention, but it seems to me that gasification is starting to take here in North America. The technology has been around for generations, and it's been big in Europe for awhile, but the American market seems to be evolving in that direction at a rapid pace.

Hopefully prices will come down and we'll all have more options in the future as a result.

 

[jklingel]

That 20" log length is a consideration, but since I have not killed a tree yet, it is not that big of a deal. I figure that having to cut the logs a little shorter will only add a tad to the overall wood collection process. I may regret that some day.... Does anyone have any unbiased data (aka, Consumer Reports type) on comparing the REAL efficiency of various gasifiers? I have only read "go European", vs American, as the Euros have refined their boilers over many, many years. Fuel prices have been high there forever, so I do not doubt that. From what I read/see/hear of the Viessmann oil boiler (they don't import their wood gasifier yet), that may be true. That is sure one nice boiler.

 

[Eric Johnson]

I think when you're into the Euro-style models (Tarm, Orlan, PK Pyro, Atmos, BioMax, EconoBurn, etc.) they're all of pretty similar design, and I believe the actual efficiencies are in the 80-90 percent range. Of course, who knows what they actually produce most of the time?

Tarm has the best warranty (20 years) and they've been around in the U.S. for a long time. The best time to buy a Tarm is in the spring, when they go on sale. At least they did this past spring with a pretty significant discount. The Orlan EKO is a little cheaper for a little bigger boiler, but the warranty is only 5 years. The one domestic mfg that comes closest to this design is the EconoBurn, which is manufactured in NY State. They were about $2,000 more than the EKO when I was shopping, but the ever-weakening dollar might help make them more competitive. Their prices haven't changed--just that the imported stuff has become more expensive. The thing that put me off was that they won't honor the warranty if you do the install yourself. No fun.

Wood length shouldn't matter unless, like me, you have a bunch of 24 to 26-inch wood and the boiler you're looking at takes a max of 20.

The OWB mfgrs make some pretty wild efficiency claims. Usually they're measuring either heat transfer efficiency or combustion efficiency--but not a combined number for the two, which is the only number that matters. Obviously, a smoky OWB can't be nearly as efficient as a clean-burning gasifier, since the smoke represents lost heat potential. So for OWB mfgrs to imply 80% efficiency is ludicrous, but people believe it. More like 40 or 50%, from what I read. I've also seen OWB dealers at trade shows toss a few chunks into the firebox and say, "That wood will burn all day long." And it will, too--BECAUSE IT'S NOT HEATING ANYTHING. Buyer beware; don't believe everything you hear, read or want to believe.

 

[ISeeDeadBTUs]

From what I read/see/hear of the Viessmann oil boiler (they don't import their wood gasifier yet), that may be true. That is sure one nice boiler.

WTH?? I didn't know Viessmann makes a wood gasifier? If it's anything like my oil unit, it's probably very good. . .and very expensive.

Tell me more, Dude!

Jimbo

 

[BrownianHeatingTech]

From what I read/see/hear of the Viessmann oil boiler (they don't import their wood gasifier yet), that may be true. That is sure one nice boiler.

WTH?? I didn't know Viessmann makes a wood gasifier? If it's anything like my oil unit, it's probably very good. . .and very expensive.

Tell me more, Dude!

Most of the European boilers are not imported to the US. The technology over there is rather impressive, although the complexity of it means that repairing a system can be an all-day affair, given the variety of parts and the prohibitive expense of keeping "one of each" on a service truck.

Oddly enough, the most popular Viessmann oil boiler in the US is actually a Biasi design and, IIRC, manufactured by a Spanish company whose name I forget.

Joe

 

[FLASHMAN]

I really take issue with people who burn Green wood in these things.

First of all, ANY dealer worth a damn will tell you, you CAN burn green wood, but you SHOULD burn seasoned, and as dry as possible.

Also, just like with ANY OTHER wood burning device, if you burn dry, seasoned wood, you'l get much higher efficiency, as well as much lower emissions. I keep seeing people saying that they're inefficient, but I know more than a few people near me with Central Boilers who burn about 8 cords of DRY PINE when they burn, usually late September to mid-May...

To me, that sounds like a bargian when you consider, in most places you can get pine FREE from land clearing businesses...

 

[ISeeDeadBTUs]

I really take issue with people who burn Green wood in these things.

First of all, ANY dealer worth a damn will tell you, you CAN burn green wood, but you SHOULD burn seasoned, and as dry as possible.

Also, just like with ANY OTHER wood burning device, if you burn dry, seasoned wood, you'l get much higher efficiency, as well as much lower emissions. I keep seeing people saying that they're inefficient, but I know more than a few people near me with Central Boilers who burn about 8 cords of DRY PINE when they burn, usually late September to mid-May...

To me, that sounds like a bargian when you consider, in most places you can get pine FREE from land clearing businesses...

LOL, not sure what they're heating, but 8 cord of dry pine would not heat my house, no matter whether it's a CB, a GW, and EKO, a tarm, a Viessmann . . .yada yada yada

Unless you have access to true PITCH PINE . . .