Going with an Outdoor Woodburning Stove... some questions

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Jul 27, 2013
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Northeast
Hi All,
I’m new to the forum but have been reading a lot of other people’s posts. Im getting ready to purchase a OWS and would like some feedback on the setup from the gurus to make sure I don’t make any costly mistakes.
Our house is about 2500sqft, has a 2 car garage and a half finished basement with baseboard heating on a 4 zone oil fired furnace.
House built in 1993, relatively well insulated, but drafty.
I have plans to add a 1500sqft work shop about 100 feet from the house so ideally I would setup the OWS in between the house and proposed work shop so I can heat it later on.
So the OWS would be about 50 feet from the house, lines running underground to the basement. There I would install a 70 plate water to water heat exchanger to keep the closed baseboard system separate and a 50 plate HX to use for hot water.
Can I setup a thermostatic valve to switch between the two systems?
If the water from the OWS is below a certain temperature, power to the furnace would turn on allowing the furnace to fill the heat call.
The OWS would be about 6 – 8 feet higher (and 50 yards further) than the furnace. Would this pose a problem and can it be remedied?
Whats a good place to buy heat exchangers from? Any brand recommendations?
Does anyone have experience getting permits in CT for a OWS? I plan to get one that’s EPA approved to avoid issues down the road.
The goal is to buy the OWS, set it up in the back yard (which would be about 10-15 feet from the house, is that ok with the smoke?) to save money on fuel this year. Next year I will level the rest of the land to start building the workshop and the permanent location of the OWS.

Thoughts, comments and suggestions would be appreciated.

Thanks,

george
 
Garn Jr. ---> Brand new unit on the market from a very reputable manufacturer. Batch burn gasser with integral 1000 gal storage. Garns do not need a chimney, they are approved for direct vent out the side of the building via a 6" class A pipe, essentially like a large pellet stove vent.

Why 2 HX's in the house? Install one on the furnace that will do the heating, DHW and keep the oil burner it in hot standby, then if the wood burner cools off the oil will kick in at a lower temp for back up.

How are you doing DHW now? Tankless coil? Eliminate that and go with an indirect fired tank on a 5th zone valve, run it's hot out into an electric tank for summer use. Or go with an indirect that has it's own electric back up element. That is a popular option for solar installs.

Then all you need is a 2nd pump, pex and HX to add the shop in later.
 
Watch your distance from the house and/or outbuildings. In my township OWB's need to be >50' from any structure. Not sure that is typical, but thought it with mentioning.
 
Most home insurance companies are now requiring a distance of 50' plus a spark arrestor on the flue.

Personally, I would not go the outdoor route. I would wait until I could put the unit in that out building you are planning and then pull the trigger. The Garn 1000 suggested may be a very viable option depending on actual heat loss from the two structures.
 
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My two cents is that if you're going to go the outdoor route put the boiler exactly where you want it from the beginning. Moving it in the future would be a pain, in my opinion.

Regarding elevation you want your boiler higher than the house, not lower, when using an open system such as most outdoor units.

Distance from house of 10-15 feet will be way too little. The outdoor units are known to smoke quite a bit. You will not be happy with this distance...
 
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Not knowing what money you have to spend or are able to spend is an issue.

The EPA compliance tests and results for OWS's are a farce and not to be
believed in my opinion and there has been a huge amount of dicusssion
about them in many forums.


Your building a work shop will provide you with the advantage of having
space for an indoor boiler and water STORAGE which will cost you less
money and also never have to deall with loading a an outdoor boiler.

Having a small wood and coal boiler and a large amount of storage
will permit you to burn a clean and hot batch burn at all times where
an outdoor will NOT do that unless it is filled half full of firebrick and an
OWS will not give you much water capacity AND the fireboxes are to large
to permit efficient batch burning.
 
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This is the route I went when I built my shed. The small building does not have a common entrance into the large building. It is very nice to have a warm dry space to tend to the fire. I keep about 10 days of wood in the small building. It maintains about 85 degrees in the winter and has 8' fluorescent lights.

gg


shed.jpg
 
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GG, I've said it before, and I'll say it again.........That is one nice clean looking building you have there! I'll third (I think) that I'm not at all fond of the idea to be out in the cold to fill a hungry firebox with frozen wood..........

My advice would echo some of the other posts here: get your building built and don't skimp on the underground piping, put a gasser and storage in the building (or your basement if you'd like) and don't look back. Then it's the best of all worlds.

TS
 
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Thank you all for the replies. I don’t currently have the space for the Garn, but it might be worth looking into and doing asetup like GooseGunner (that is so sweet).
But that would imply waiting another year or two during which time I would have spent over $5k on oil, probably more.. money that could go towards the amortization of the OWB. That’s why I was hoping I could set it up temporarily this year then move it next year after the land is leveled.
Right now I have a oil fired furnace with hot water coil which is connected to a boiler mate. I assume I need two HXs, one for the heat and the other for the hot water?

I was hoping to have this project done for about $7,500 doing all the work myself.

Looking into CT law, I found this craziness:
“Must have a chimney that is more than the height of the roof peaks of residences located within 500 feet of the OWF, provided the chimney height is not more than 55 feet (This is to the actual roof peak, not the mid-line of the slope).

A chimney’s height is limited to no more than 55 feet, from ground level, at its installed location. (If this is not more than the height of the roof peaks of residences located within 500 feet of the OWF, then the OWF must not be installed). “
 
House built in 1993, relatively well insulated, but drafty.

It sounds to me like a blower door test with IR imaging/smoke stick is the place to start. Finding and fixing as many of those air leaks as possible will probably pay for itself in the first year and you will be more comfortable in winter and summer! (unless you leave windows open all the time)

I was hoping to have this project done for about $7,500 doing all the work myself.

I think it will be tough to meet that number no matter what options you go with. 100 ft of underground lines done right and you are probably looking at least $1500 if you have a backhoe-likely more and you don't want to go cheap as you will end up with a Heat Loss Horror Show. Speaking of which, I would be surprised if ANY OWB(gasser or not) will lose less a 2-3000 btu/hr, 24/7.....Yikes. After the underground lines, pumps, HX's etc, you might have 5k $ to put towards a boiler-not many choices here.

And IMO that chimney craziness is just another reason to NOT go with an OWB.

So here is another vote to keep the boiler in a building close to your nice dry wood and consider storage if at all possible.

Noah
 
FYI to all.
Floydian brought up a good point re jacket heat loss from an OWB. I had the opportunity to do a little study on one a few years ago. I won't name the manufacturer but it had foam insulation and was the second size up from the smallest. Using a starting point of 182* indicated on the display, shutting off the circulating pump to the load and calculating btu loss by observing water temp drop x water capacity in pounds, showed just over 4,500/hour or a little over 100,000 per day.

This picture shows what one owner did with a Windhager that replaced an OWB that sat on the same cement slab as the little building.

Also, regarding the spec's for the chimney......It should be obvious that the authorities there are purposely making installation of any OWB almost impossible. That should tell you something........
 

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You are looking at boilers. Boilers heat water. You will not be able to do a remote install for $7500 unless you cut all corners that can be cut. In this case you will be a slave to your boiler and burn through many cords of wood per year than you should like too. Thats the bottom line jack. Likely you will spend the money you saved in oil relocating the boiler at a later date. Also you can forego the expensive heat exchangers if you go with a closed system boiler. Get going on your workshop pronto and collect wood so you can do things right the first time around and save yourself headaches. Btw, how much wood do you have properly seasoned and dry enough for a gasser (gasification boilers are the way to go) that would be ready for this year?
 
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