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Indoor or Outdoor Boiler to Heat Garage?

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by dook, Dec 11, 2012.

  1. dook

    dook New Member

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    I'm in the process of designing my next home and trying to figure out how to heat the garage in a manner that will not cause insurance companies to reject me.

    I understand that a woodstove in a garage is not kosher, although most rural people around here do just that without problems. There are no codes in this rural Montana county, the only objective is qualifying for insurance.

    I've read many threads here about heating garages and NFPA standards and narrowed things down to this:

    It seems that Outdoor wood boilers have a reputation of using MUCH more wood to heat a given area than indoor ones because heat is not radiated inside the structure to be heated. Not knowing much about boilers, it seems to me that if OWB's radiate that much heat, the issue is insulation.

    Would it be more efficient to build a super-insulated shack 2 feet from the garage to house an indoor boiler and a couple cords of wood?

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  2. bupalos

    bupalos Member

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    If you have space in the garage and that's where you want to put it, I'd shop insurance companies until someone wants the business. I wouldn't say "will you let me have one." I'd say, "I'm putting one in there, do you want to insure me or let the other company do it."

    There is little to nothing inherently more dangerous about burning wood in a modern gassifier than having any other type of boiler in there.
  3. dook

    dook New Member

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    I wish it were that easy. Getting someone to insure you is difficult. Insurance companies prefer not to insure people with large tracts of land, off-grid homes and log homes. When you fall into all 3 of those categories it's nearly impossible.
    As I understand it, gas boilers and oil furnaces are not acceptable in garages either.
  4. juanni

    juanni New Member

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    My solution is to build a home without combustibles and never have to purchase fire insurance.

    Think of the money, hassle and frustration of dealing with those insurance companies over a lifetime, that you can eliminate. :)
  5. StihlHead

    StihlHead Guest


    The OWB inefficiency issue is not with the insulation, and insulating them more would have little effect on the amount of wood that you burn. It is the way that they operate that causes them to run inefficiently. They go into starved air smolder mode between fire modes, and that makes charcoal as the wood stays hot and the wood gasses escape. You cannot just add insulation over them, nor do you want to build a shed around them (though I know people that have done that). They come in an insulated housing, usually sheet metal over foam over the boiler steel. The advantage of an OWB is that they can run for a reasonably long time between loading, as they store energy in a smaller water tank in the boiler housing and in the unburned wood. You can also burn any wood in there (wet, green, dry, pithy), and you do not need to split the wood that goes in them. Not having to split wood was a HUGE advantage. Also you do not need a separate water storage tank using them. They can also be installed pretty much anywhere outside and take up no indoor space. You can also split the lines and run multiple pumps to heat various types of things, like garages, hot tubs, DHW, space heaters, greenhouses, hydronic home floor heating and concrete walkways, pools, or whatever. The other advantage is that they are outside, and so the wood, smoke, ash, etc. is all outside, and they do not incur a liability for fire insurance.

    Now that said, many states do not allow older style OWBs to be installed and they require newer EPA approved ones only. In your case that is not an issue though, and older OWBs are half the price of newer EPA ones. Newer EPA ones are basically gassifiers, and they require that you burn only well seasoned dry wood. They are more efficient and smoke less, but there is much controversy as to how efficient they are.

    I designed and retrofitted a classic style Central Boiler OWB into my ex's house that had an electric hydronic floor heating system and an electric DHW. I used a single loop of 1 inch PEX and ran the line to a hydronic floor bypass loop Hx and then to the DHW Hx. It worked as designed, and basically paid for itself in about 4 years of use. We were also able to keep the house a lot warmer with the OWB than with electricity. It ate about 10 cords of wood a year, but the ex has vast acres of timberland to harvest firewood from, so she has a lifetime supply of firewood for free (well, labor and gas money). Fire insurance was not an issue, as it was detached from the house by a little over 6 feet (all you need in Oregon for fire codes here). We found that loading the boiler half full more times a day (usually twice) was more efficient, as the more wood you put in them the more charcoal is made before it actually burns. Wood gassifiers with a storage tank are more efficient as they burn all the wood at once and store the heat in water. However, they require an insulated storage tank, and they need to be fed dry seasoned wood. There are also many issues with systems like the Greenwood and others with bricks cracking and the like.

    We chose the smallest classic CB OWB as a compromise on price, quality, good company reputation, good sales rep, size, fire insurance issues, existing heating systmes to retrofit, availability, and safety. They are open loop systems so if they boil over, that's all they do. Water and steam gush out, the steam takes away the excess heat, and that's it. Nothing else happens in a boil-over. They are UL approved. Yes, they eat wood. No, they do not smoke nearly as much as claimed, and actually they smoke a lot less than a typical pre-EPA wood stove. Usually they only smoke for a few minutes when the damper opens and they go into burn mode. At full fire and in closed damper mode, they hardly smoke, if at all.
    dook likes this.
  6. StihlHead

    StihlHead Guest

    If you are going to get a mortgage on your home, it does not work that way. You need fire insurance in order to get a loan. Even if it is built of concrete and steel.
  7. juanni

    juanni New Member

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    No mortgage, cut out the Banksters too.
  8. Got a way to avoid taxes?
  9. stee6043

    stee6043 Minister of Fire

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    I've been through two insurance companies in the past few years and heating with wood has been little more than the check of a box, a few extra dollars per year and a couple of photos of the wood burner. I had no idea some folks struggle to get and/or maintain "fire insurance".

    Regardless, I'd echo what was stated above. You won't vastly improve the efficiency of an OWB but hyper-insulating it. The massive firebox and massive output numbers are why they are inefficient. They can't help but idle all day long....
  10. dook

    dook New Member

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    Thanks for the replies. The property will not be financed. I'm not very worried about fire. If it burns down, I'll just rebuilt it. The reason I need insurance is a much more dangerous and expensive hazard.....LAWYERS. I have 185 unfenced acres. In order to get lawyer insurance you have to buy homeowners. No way around it. If not for that, I'd build it as I please, like most everyone else around here and put a homemade woodstove in the shop and burn 3 cords of pine a year.

    Thanks for you detailed reply, Stihlhead. The "10 cords a year" part is the hurdle. That's what everyone else has told me about OWB's. Seven extra cords a year would be the added insurance premium to protect myself against lawyers. What if I got an indoor wood boiler and built an insulated shack around it? How many cords? There is plenty of beetle-killed dry pine around here and it's not hard to split when it's cold outside. I just don't want to split 10 cords of it to keep a 1600 square foot insulated garage/shop at a tolerable 55 degrees every winter.
  11. juanni

    juanni New Member

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    Avoid, no.
    Minimize by purchasing property in a low tax state with few "essential services".:)
    Self employed, use every deduction and simply work less, and spend the additional free time saving money by building my own house, repairing my own car etc...
    Taylor Sutherland likes this.
  12. maple1

    maple1 Minister of Fire

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    'Lawyer Insurance'?
  13. You sound like me :) I did/do all of the above and grow a good portion of our food. My two biggest expenses are property taxes and insurance. Living in Maine I can't do much abut either.
  14. StihlHead

    StihlHead Guest

    I do not have a mortgage here either, but I have fire insurance. Mainly for liability. O/w someone trips and falls onto your property, and it becomes theirs in civil court. Also if the place does burn down, I get a new house built here.
  15. juanni

    juanni New Member

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    I will have liability insurance, just not fire.
  16. juanni

    juanni New Member

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    I think it is the way to go. I roughed in garden plot but probably won't have time to work it next spring.

    I have had the high paying job in the city and the big house.

    Between all the taxes, fees, hassles, adversarial relationships with all the various govt bureaucracies and having to pay someone to do repairs because you don't have the time or place to do it..... it isn't worth it and you don't get ahead.

    The last time I registered a car there, I ended up having to go through a long winded VIN inspection process because someone typoed 1 digit on my VIN title wrong.

    After I got that straigtened out a week later I get a notice that I owe then ONE dollar more, someone else made an error. Couldn't just send a personal check, had to be a MO, CC or come in and pay cash.

    3 weeks later I got a notice my license was suspended because I didn't have vehicle insurance.
    I did, they didn't ask and it was another trip in.


    Now I go down to the county courthouse, breeze up to the counter, no nasty clerk, no bulletproof glass, no smog, just a smile, a 2 minute transaction, a thank you and out the door.
    Ahhhhhhhhh..........
  17. StihlHead

    StihlHead Guest

    Yes, liability insurance. I have a heavy policy rider on top of my fire insurance here. Costs me an extra $20 a year for $300k in liability insurance. Wood stove here was a non-issue for fire insurance, and I am not sure it costs me a nickle more than w/o it. They did not want to know anything about it, other than that it is there. It is on the original building permit with the house on the county records though.

    The OWB does not burn 4x the wood than a super insulated wizz-bang "whatever" system. More like 20%-50% more wood, depending on the model and the size/demand/location/design, etc. They are not as bad as people make them out to be. NY state and New England villinized OWBs for a long time. The EPA OWBs are better, and basically they are wood gassifiers like most indoor boilers but they do not require a separate holding tank. Same design gassifier firebox though. As I said before, you do not need to split cordwood for OWBs. They burn logs. I cut larger rounds into quarters or halves, and whatever size the ex could lift was the maximum. We cut mainly 2' DBH trees and down for feeding the OWB, and usually I cut logs 2-3 foot long by about a foot in diameter, and there were always smaller stuff from limbs and tops. Splits are not required though, and a big reason I was grinning when I saw the OWB in operation at the dealer's house. He was burning 1 foot diameter logs in there, 3 foot long. No problem.

    Several issues with indoor boiler systems: they are all EPA controlled and they require holding tanks for heat storage. Insualtion of the boiler is not the issue there either. You are thinking along some lines that are not real aspects of what is going on in wood fired boilers. An super insulated shack does not get you much of anything more tham a simple waterproof single insulated shack for an indoor boiler built away from a building. Insulate the crap out of your house/garage/shop and the holding tank, but not the boiler. The boilers are not where the most heat is being lost. Heating 1600 sq ft of garage space is going to eat wood in any system you get. My ex's house has 2200 sq ft and insulated, but she had 10 skylights and 8 sliding glass doows, and windows galore. That place leaked heat like a sieve. A better designed home would have used half the wood, even in an OWB.

    If you want the most efficient system, I would build a Russian fireplace along one wall, or in the center of the shop/garage and have the firebox on an outside wall, facing out. Build a small fire and burn it hot and that's it. It will heat the firebricks and radiate heat for hours. Simple system, no moving parts, no issues with the EPA, outside air supply built into the design, and the wood, bugs, ash and smoke all stay outside, and they are simple systems to operate. Contrary to common opinion, they do not cake up with creosote, as the fire is burned small and hot and fast, so that leads to far less smoke to build up on the inside liners. I have a friend that designs them up near Crater Lake, and he burns 1/2 the wood that he burned using a good indoor stove with his Russian fireplace. They are similar in effect for burning and heating as a wood gassifier. They both burn small hot fires and store the heat that is radiated out for a period of time after burning. Indoor gassifiers are relly spendy though, and water tank storage systems require a lot of plumbing, pumps, valves, feedback systems, and you need a Hx system for distributing the heat. Copper is REALLY forking spendy these days. The EPA OWBs work in similar fashion, but they do not require added holding tanks that the indoor models do (they have a tank in the boiler unit) and they are self-contained. All they need is a slab, or level gravel, or RR tie foundations. I would avoid pressurized systems as well, for many reasons. Lots of debate on that as well, but I have seen heating systems go bad. I believe in KISS...

    All of these systems require that you be there to load the firewood. That is the drawback in any wood heating system though. Its not like NG, propane, or electricity.
    dook likes this.
  18. dook

    dook New Member

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    And no liability insurance either.

    I currently heat my 1400 square foot well insulated home to 73 degrees f with 3 cords a year using an ordinary woodstove. It seems I should be able to heat a 1600' insulated shop to 55 degrees with about the same 3 cords. But the problem seems to be that if I want lawyer (liability) insurance I have to add 7 more cords a year to the equation.

    My current off grid home is heated by a woodstove and sits on 200 acres. It took me several weeks of searching to find an insurer and homeowners insurance costs me $1350 a year.
    I paid over 20K in car, home and boat insurance to State Farm over the last 2 decades. I had them come out and evaluate my home for homeowners insurance and they called me the next day and said "NO". They refused to give a reason. My neighbors have a similar home, but it's a log home. They told me they were dropped after several years of no claims simply because the insurer was no longer insuring log homes.

    Methinks our rulers want the human cattle herded into the cities where "one third of our subjects will keep the rest under observation".
  19. flyingcow

    flyingcow Minister of Fire

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    Most indoor gassers do not need storage, mine does, but all do not.. My indoor unit is next door in my garage. My wood is in there also.

    The new EPA compliant OWB's are not as efficient as a true gasser, with the exception of Econoburn or Portage and Main. But my neighbor has an E-Classic EPA compliant OWB. It has a second chamber, burns a bit cleaner than the old Classics' but not by much.

    A good rule of thumb if you're burning oil.
    1 cord of seasoned wood= 100 gals of oil in a E-Classic.(this was info given to me by the salesman)
    1 cord of seasoned wood=150 to 175 gals of oil. That info was given to me by this forum. And I have found it to be true.

    A true gasser doesn't smoke, majority of OWb's do. Thats why they were "vilified" in most semi urban areas.

    You're in the country, smoking out neighbors is not a biggie.

    Sounds like you've got a tight house you're living in. 3 cord? Seems like if you're that meticulous about building, you're shop won't need much either. Maybe another 3 cord? An OWb or gasser will run you into what?.......10/15,000 bucks? E-Classic's are pushing $12,000. Eko's maybe $5000? Vigas w/Lambda $7,000 or less? Plus DIY storage for maybe $3,000 max?


    Oh yaeh...just for kicks look at a GARN. Don't be intimidated cause it's the size of a mini-sub. Take a look.
    dook likes this.
  20. StihlHead

    StihlHead Guest

    Wow. I have a dubba wyde on an acre with a wood stove w/o the manf. plate on it. I have 'valuation insurance' for $50k replacement value as it has accessory buildings: detached shop and garage, attached cabana in back, covered porches, and a well house. Its only about $400 a year. Truck insurance is another $400 a year. Medical insurance is the big one... $250 a month. But I beat cancer a few years back and that cost them more than I have paid or will likely pay in insurance fees. I dunno why you cannot get house insurance though. Is it built on skids or something? This trailer is just sitting on concrete blocks. No one ever came to look at it. Its through Farmers (USAA will not cover HUD homes).

    200 acres is a lot of land. My ex has land that size, and it was a chore to manage it all. In my experience, it is about 190 ares too many for my likes. :)

    3 cords of wood is good for Montana. I doubt that anything would burn much less than that. Well insulated is the key. I keep this std. insulated metal box about 68 degrees but burn into July with all the rain we get here. I burn about 3 cords as well, mostly hardwood and doug fir that has the same or better heat. This year I am only though a half cord though, it has been warm up until recently.
  21. dook

    dook New Member

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    So, what's the difference between indoor and outdoor boilers other than where they're designed to be located? Are indoor boilers more efficient and less expensive? I'm thinking of putting an indoor boiler in a shack a couple feet from the garage.

    I think one reason my insurance is so expensive is it would take 45 minutes for a fire truck to climb up my driveway, but I'm not certain my current carrier knows that my house is 1300' elevation above my mailbox. The other is liability on the acres.
  22. kopeck

    kopeck Minister of Fire

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    The big difference is you are not loosing heat between the boiler and your house. Those underground runs bleed some heat no matter how well they're insulated. Now if you put yours in a shed then yes, you will be in the same boat in that respect.

    The indoor models are more refined. From what I've read the new gasification OWB use secondary combustion more for smoke control then efficiency.

    You also loose all of the heat radiating from the boiler when it's sitting outside.

    It's really all about what you want. If you don't want the mess in side and you are willing to burn more wood and walk out side in unpleasant weather to feed the boiler then it should work for you. I like being able to load my boiler with out getting bundled up, I don't mind the bit of a mess storing the wood inside causes and I really do like the idea of burning less wood.

    Each has their place, it's a life style thing really.

    K
  23. goosegunner

    goosegunner Minister of Fire

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    OWB companies must have some miracle insulation. Temperature differential, something with 2" of spray foam sitting outside when it's -10 is going to lose more heat than if it is sitting in a heated space.

    gg
  24. StihlHead

    StihlHead Guest

    Pretty meaningless in the grand scheme of things. Heat losses are small from insulation and loss vs indoor boiler compared to differences in efficiency of the two types of boilers. The main driver of indoor vs outdoor boilers has been that the EPA has had control of wood burning appliances INSIDE and hence they are mostly cleaner burning wood gassifiers. OWBs have been exempt, and thus are typically less efficient and tend to smoke more (not all of them do though).

    If you keep the distance short, this becomes a non-issue. If you bury and insulate them they will not lose much heat. Expose the Pex to ground water and you will lose a ton of heat. All depends on the install. This issue would be the same with an indoor boiler put in a shed away from the garage/shop. OP issues is that he is trying to get around the insurance issue of having a woodburning appliance in the garage.

    Having an OWB for about 3 years loading it outside was also a non-issue. I located our's the edge of the garage eves, so the trek was covered. Going outside and getting in touch with reality was actually a good thing. Especially being cooped up with cabin feaver this time of year.
    dook likes this.
  25. BoilerMan

    BoilerMan Minister of Fire

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    It's funny I was just on the phone talking to someone about all these things. Indoor vs. outdoor, gasser vs. conventional.

    To answer some questions and to highlight some post on here.

    Indoor vs. outdoor is different than conventional vs. gasser.
    OWB are usually conventional as Stihlhead sescribed and can be somewhat clean/efficient if operated with some brains. However they are not and never will be as efficient as even an indoor conventional wood boiler, due to heat loss in underground and lost heat through the jacket and lost heat from the chimney that would otherwise be inside the building envelope.
    Outdoor gassers are better, but still suffer from the same as above.

    A boiler shed installation, is (on here) an indoor gasser installed in some type of building usually with wood storage in it, there is still underground line loss and expense if this building is not attached to the home. All wood and mess is outside, no lost floor space from the boiler itself or wood storage, added expense of building the shed and underground lines (if needed).

    An indoor boiler is inherrantly the most efficient due to all losses are inside the building envelope, but so is the wood and associated mess.

    An indoor gasser is the most efficient, and with storage the most convientent also.

    All boiler installations indoor or outdoor will be easier to operate with storage, unless the boiler design incorporates storage (most OWB, Garn etc.).

    There are alot of variables here, and confusion from people whe think all OWB are smoke dragons (most are, but not all) Also there are two types of boilers, gassifier and conventional (referred to as 'smoke dragon'). I've owned and operated a smoke dragon and gassifier (both indoor installations). I operated my SD well, and it did make quite a bit of smoke, or what most would consider normal for someone burns wood. I have a gasser now and can tell you there is NO smoke (only at startup for <5 min.) and it makes way more heat for the same amount of wood I load.

    If you burn wood, it should be dry. If you don't season your wood, then you reap what you sow. Water doesn't burn and has to be boiler out of the wood before it can produce any heat to heat your building THIS IS THE TRUTH!

    TS
    dook likes this.

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