OUTDOOR Wood/Coal Furnaces...Seeking advice before we buy??

Well in your location, with a lot of family muscle to help, a wood boiler may be the best for you..

The idea of tossing large quatities of wood into a large firebox, and let it smolder and cook at low temps, coating the inside of the boiler with creosote.. just makes me shudder... But I suppose if you have lots of free wood, and I mean LOTS of wood, and can get the family to participate in the yearly process of cutting, splitting, stacking, then the daily process of unstacking, and loading the firebox... I'ts this process that is so much work, that makes most people love coal...

You are not going to get too many more OWB -bashing stories on here,, there aren't that many folks who had OWBs... I can think of less than 6 members that are former OWB owners..

Here is a thread that is developing: Anybody Using Hawken or Global Hydronics HE-4000?
He has an OWB, maybe he can pass on some info??
Take a look at the inside of his OWB,, all that black goop is unburnt wood, gassified, then liquified.. insulating the inside of the boiler.. Not good..

Greg L

I did read that whole thread. I also called Tarm about their Gassification boilers, which sound nice, but no coal option. Not what I wanted to hear. More important than the BIG door and only feeding the furnace maybe twice a day ---is the option to use Wood AND COAL. Especially this coming winter, we know we will NOT have enough Dried Good wood to fuel an all Wood furnace. So we will be using more coal this coming winter-for sure. If you can list off hand all the main problems with the OUTDOOR Boiler over the design of the Indoor Coal/wood boiler in the shed, what you feel the outdoor boilers are clearly lacking ..... please state them here. This may just make us decide to build that shed and get an indoor design over any OutDoor we can find. What is most important to us is .... #1) must be Outside #2) Must be able to use wood and coal #3) Effientcy, not wasting fuel and of coarse Safety and durabilty. Maybe I should start a thread for Coal/wood Boilers in a Shed - heating house. One question I do have though is this, does this mean our chimney on the shed has to be REALLY REALLY tall ? I get the impression this is one of the bad designs of the OUtDoor Furances?

OverRunWithSons wrote:I want some of those unhappy outdoor wood boiler people to post on here. I really want to hear from them & their problems with thier particular product.

Like I said in an earlier post. The biggest issue with my heatmor is the fact that my wood consumption at least doubled by going with an OWB. That and tending it 4 times a day in cold weather. But I tended the indoor wood furnace that much on the cold days also. My OWB will throw an orange flame out the chimney at night. Thats not good. Lots of BTU's going out to the atmosphere.

I remember one forum member calling his OWB a 'wood eater'.. consuming huge quatities of wood.

The problem with most OWBs is that the huge pile of smoldering firewood makes huge quantities of creosote,, this coats the inside of the boiler surfaces. This then insulates the surfaces from transfering heat to the water on the other side of the steel.
The more clean surface area you have, the more heat you get out of the firebox before the fire's heat goes up the chimney. Look at the cut-away drawings of the OWB's and then the cutaway drawings of the coal boilers.. you can see that the coal boilers have more passageways, more surfaces to pull heat from the firebox into the water... But, an anthracite coal fire is a clean fire. only some fine fly ash in the fire byproducts, and this ash wont 'hang' on vertical surfaces,, so it falls to the bottom of the boiler where it can be removed...
A wood fire will have that black sticky gooey tar adhering to all surfaces, unless you burn the wood like a gassification boiler does.. which OWBs just cannot without boiling the water, because they hold so much fuel..

So a good boiler has lots of surface area, to absorb lots of heat.. this is how I designed my own boiler,, with lots of surface area, that could all be reached through cleanout doors and surfaces scraped clean with a grden hoe.. No OWBs have this feature that I know of.. I have the heat/smoke making three passes through heat absorbing water jackets, all of which can be cleaned,,

A good burning appliance will extract as much heat from the fire as possible, before giving it up and letting it go up the chimney..

Yes a reasonably tall chimney is needed,, if you build a 12'x16' shed with a 6/12 roof peak, and put a masonry chimney going through the peak, and add about 4' above the peak, this will be about a 16-18' chimney,, should be enough as long as there are no buildings blocking the prevailing wind...

Lots to read and learn.. let this thread keep growing, and maturing.. more info will come.. I'm not busy right now, [actually procrastinating on jobs really bad] so I have been able to answer a lot.. but there are several other former OWB burners here,, hopefully they will chime in.

Greg L

I'm sure there are a lot of people happy with them, it's really a subjective question. The point is if you have someone that burned wood and switched to coal they'll tell you coal is better. The only advantage wood has over coal is that it produces less ash.

my plummer friend recommend putting coal in my new house, he said that was the way to go and that was what he was going to do. i put in a coal stoker efm df520, he put in a odw. he now is going to install a efm df520, actually he just became a efm dealer. he had a supply of wood but said it only worked okay if the wood was big logs. small dry wood just burned to fast. partly green wood was the best because it lasted longer. he was in our shop one day and looked at our stoker, and seen that we only had to take out the ashes evey day and fill the bin maybe once a week, and made the decition to switch to coal. now he wished he istalled years ago. by the way he payed around 7500 for his odw boiler

We just visited 2 people today and talked to a 3rd who has a HARDY outdoor Furance, they all LOVED them, they all admitted it takes alot of time & ALOT of wood, but all of these people , plus another who had a Central Boiler, -and the other who had the Heatmor we seen a few days ago-just loved their outdoor furances. No complaints really other than "they can smoke" and they take alot of wood. All of them had WOOD for free in their own yard though, so this was not a problem. A couple of them used Coal also. Same situation for us, we have the free wood if we take the time to do all the work. Just thought I would relay what happend today in my quest for figuring out what we plan to do. Thanks to all.

The thing is if you buy wood cut and split at market value it costs more than coal, if you have it then of course the price goes down but the workload goes up quite a bit. Probably not so much with a OWB because you can throw such large pieces in it... If it were me... I'd burn coal and sell the wood.

It's funny, I posted this same question on a wood message board http://www.arboristsite.com/showthread. ... ost1026660 and these people just LOVE their outdoor furances, in one day, I had like 8 very very encouraging answers , no matter what brand they had, they loved it. But like you said, they are able to get Free wood. That makes all the difference. We would not consider it ourselves if we had to pay for wood. We will have to buy a Hauler and build a wood shed though. But those are small things in comparaison to the price of oil right now. I think we decided on a Hardy furnace with coal option. I thank you all for your help.

I'm sure they do love it but I'd venture to guess most of them have never burned anthracite coal. You won't find an ex wood burner that would choose wood over anthracite. On the other hand wood is plentiful in most states and anthracite becomes less of an option the farther you get away from NEPA. You really need to evaluate your situation and make the best decision for yourself.

Try http://www.hearth.com too if you want some more reading on wood. Their forum is huge: http://www.hearth.com/econtent/index.php/forums/

OverRunWithSons wrote: these people just LOVE their outdoor furances,
.

We humans are an odd lot. We find it tough to spend $10,000 on a device and then say "It's too much work, it uses too much fuel, it isn't as good as I'd hoped". When we spend ten grand on something, we love it!

That being said, I know one guy that installed an outdoor wood boiler last year. He does love it. He also has a good supply of free wood.

OverRunWithSons, congradulation on finding the hottest(no pon intended), and most informative website going.There's a pretty smart bunch of guys posting on this site. I found thissite because I was a unhappy wood boiler user. The thing about wood boilers is that they make alot of creasote. Way more than a regular wood stove or furnace. The boiler part never really warms up so it makes all kinds of runny ,smelly creasote. MY outdoor boiler smelled so strong you could smell this overpowering smell 200 yards away. Not considering the smell part, the other thing was the constant tending of the fire. That wasn't so big a thing really. I like the caveman TV just as much as anybody else. But,,,, If you have a bunch of creasote buildup in your boiler and chimney stack and change to a coal fire, you will be asking for trouble. The coal burns SOOOOOOO very much hotter that you will be causing the creasote to ignite.Chimney fires. I think you would be causing damage to your boiler and chimney and whatever the sparks land on. You might be better off burning one or the other all the time and not mixing. Either way it would be prudent to install the unit of choice down wind. Just a word of advise freely given. Scott

On the other hand wood is plentiful in most states and anthracite becomes less of an option the farther you get away from NEPA

What is NEPA?

Northeastern Pennsylvania. Anthracite coal is only mined in NEPA.

Freddy wrote:

OverRunWithSons wrote: these people just LOVE their outdoor furances,
.

We humans are an odd lot. We find it tough to spend $10,000 on a device and then say "It's too much work, it uses too much fuel, it isn't as good as I'd hoped". When we spend ten grand on something, we love it!

That being said, I know one guy that installed an outdoor wood boiler last year. He does love it. He also has a good supply of free wood.

What Freddy said! If your wood is free, AND you and your neighbors don't mind alot of smoke, AND you've got a strong back and lots of time to spend feeding it twice a day, than they are a good choice. Like Richard said also, you won't find an ex wood burning coal burner who would ever go back to wood.