# needing information on pressurized wood boilers



## ditchdigger (Mar 10, 2014)

Hello everyone, I'm new to the forum and looking for information after doing a lot of reading already.   I'm currently using an unpressurized wood boiler, have had it for seven years and am wanting to upgrade to a much more efficient pressurized wood boiler.    I'm currently heating a shop and house, and would like to add another house, a shop addition and two garages, along with a boiler and wood storage building in the future.    

I'm not sure I want a stand alone outdoor type boiler, like I've got now, what I'm thinking is putting up a building to install an indoor unit inside it, we already have underground lines to one house and the shop now, the house has forced air and we use a heat exchanger and also a side arm for the hot water heater.   My shop has infloor heat in the main shop and office, but this winter, is the first winter we had the shop up and running and have had issues with my current boiler keeping up to my heat demands now, without adding any more to the system.    

I'm wanting information on the efficiency of some of the pressurized boilers on the market, what I have right now it burns wood and I'm thinking an after thought is to put out some heat in the process, but is far from efficient as I can get, this winter has been an eye opener as to needing something much more efficient.    

I'm not sure how long of a post you folks want to read, I can add any information you want to know about, square footage, insulation types and thickness's, line length's and sizes and anything else.


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## webbie (Mar 10, 2014)

Lots of folks here with lots of boilers - but you should take a look at the Garn and Garn Jr.....just as a start! They are super-efficient and include the storage you need and fit well into the outbuilding scenarios.

http://www.garn.com


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## bmblank (Mar 10, 2014)

I've grown up with Tarm. My solo innova is awesome. It's all I know though.


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## ditchdigger (Mar 11, 2014)

webbie said:


> Lots of folks here with lots of boilers - but you should take a look at the Garn and Garn Jr.....just as a start! They are super-efficient and include the storage you need and fit well into the outbuilding scenarios.
> 
> http://www.garn.com



Isn't the Garn an unpressurized boiler?    I've been told since I bought my current owb that if I go pressurized I would eliminate a lot of issues with the boiler rusting from the inside out through the water jacket, which seems to be a major problem I've been having with my unpressurized boiler now, is this true or just a sales hype I've been given?

I've been around a couple fuel oil boilers in the past, one we lived with in a house for almost 20 years it worked and preformed great, two lp gas boilers and neither of them gave me any trouble as far as leaks and rusting and also a couple in house forced air wood furnaces and those didn't cause me any grief either.     So from past experience I've had great luck with pressurized boilers, not saying it would eliminate all my issues, but I was hoping it would solve a lot of them.    

I've looked at the information on the web about the Wood Gun boilers, know nothing about them, never seen one in person and know nobody that has one, haven't as of yet got a hold of anyone at the company, its either busy or they don't call back when I leave a message.    

The next question I have or at least wanting to know if what I've been told is true or not, that there is no such thing as an accurate means to get an efficiency rating on a wood boiler, with the variables in the kind of wood burned, moisture content, atmosphere pressure and a host of other variables involved, then how do some of the companies rate theirs, with an efficiency rating on them?     Sorry if its a stupid question, but I've been given so much information from way too many people I'm now more confused than I was when I started.   I've looked at some survey's of efficiency's of outdoor wood boilers, and those won't list the manufacturer or model number in their statistics, not sure what good they do anyone, but is there a comparison somewhere of the different makes and models of wood boilers that do list the efficiency of them?


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## mike van (Mar 11, 2014)

"Isn't the Garn an unpressurized boiler?"  Yes it is, I don't believe that they have issues with rusting out though. They test your water for free twice a year, and you have to put good dry wood in them,  Some Garns 20+ years no rust problems. The only "issue" I see with an  unpressurized boiler is you need a 400.00 + heat exchanger.  You don't need expansion chambers though, or have to worry about blow-off valves, over firing, etc. The 1000 gals of water in my Garn Jr gives a lot of room for error about over firing. I did mine once, on purpose, steam comes out a pipe until it cools to below 212.


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## ditchdigger (Mar 11, 2014)

bmblank said:


> I've grown up with Tarm. My solo innova is awesome. It's all I know though.


By the looks of their website, they don't make a unit big enough for what I'll need, nice looking unit though, thanks for the reply of what unit you have.  

Has anyone had an outdoor wood boiler and gone to a gasification unit and can tell me how much less wood they burned with the gasification boiler?


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## NE WOOD BURNER (Mar 11, 2014)

ditchdigger said:


> I'm not sure how long of a post you folks want to read, I can add any information you want to know about, square footage, insulation types and thickness's, line length's and sizes and anything else.


Bingo! What brand is your current boiler? What method of UG piping did you use? How much wood did you burn with your current set up?


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## Karl_northwind (Mar 11, 2014)

The efficiency rating process in the US hasn't been hashed out yet, so you'll see all sorts of numbers.  at least the europeans have a proper system sorted out.  

the big thing you want to avoid is cycling a boiler. 

 Garn avoids this by putting all the heat into water at full speed (over 4-5 hours) and then using that heat for 12-24 hours.  
they are unpressurized for lots of good reasons.  they deal with the corrosion with anode rods and a serious commercial water treatment program.  I have seen garns 20+ years old with no corrosion.  I think you'll find that even a 2000 might be too small for what you want.  the size and insulation levels of the houses and shops will determine the best course of action.  

Wood gun works similarly, but IMHO you'll want to add storage.  even if they say you don't need it.  there are several people here that have them and can talk about storage vs no storage. 

information from you will help.  size and age/insulation level of houses and shops, distance between buildings, etc.....


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## infinitymike (Mar 11, 2014)

Hi and welcome to the forum.

This question will bring a lot of opinions and personal preferences so keep that in mind.


I'm glad you brought up the Wood Gun.
Although I'm not heating anything of the size you are, I'm very happy with the Wood Gun.
I'm very surprised that you haven't been ble to get in tough with them.
When ever I call, they either pick up the phone or call back the same day.

I believe Jebetty has installed 2 Wood Guns in a school or some institution and they work well for him.
Wood Gun definitely makes some monster size units which should handle your heat loads.

As far as I know, Efficiency is based on a moisture content of 20%.


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## henfruit (Mar 11, 2014)

How big of a boiler are you looking for? Vigas has one that will 341,000 btus an hour.


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## NE WOOD BURNER (Mar 11, 2014)

Oh boy! potential for 6 structures if I read your post correctly.
I would think a heat loss of your current structures and a design heat loss of your potential structures would be helpful for sizing your boiler.
since you are proposing an addition and several garages and another home you are in a good shape for designing a central heating source. I would incorporate your central system into the design of these new structures.
I would suggest posting a simple sketch to start with approximate S.F. and distances to existing and proposed structures. The Brand of boiler to me at this point is not as relevant for early planning.
An open mind to the system itself prior to boiler selection is a key element to entire efficiency.
There are many experienced minds here and most brands are represented here.
If you do not have a stock pile of wood drying currently I would get that going first CSS.
Low temp heat emitters are also important for the thermal storage component.

Here is a post that turned out very successful from this site. much smaller scale than yours but good results. 

https://www.hearth.com/talk/threads/e-classic-1450-or-pm-optimizer-250.113337/


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## Fred61 (Mar 11, 2014)

Although outdoor wood boilers are notoriously inefficient they will usually heat a large area as long as you put a full forest through the firebox. What OWB do you have? Are you sure you are not loosing heat to the ground on your UG runs? Is the slab heat built properly with good insulation and vapor barriers?

Usually when someone has a heat load such as what you are proposing, the guys here recommend a Garn but you may have a problem getting the full output of the unit because of your need for higher temperatures for your water to air heat exchanger in the house. The same will go for any gasser with storage since you will not be able to use all of the stored energy because the temperature will be below useful levels for your heat exchanger.


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## Vizsla (Mar 11, 2014)

With 500,000BTU/h Tarms and 1,000,000 BTU/h Econoburns  available, before we even get into multi units there is no heat load too big with these or other indoor models. Still curious as to what boiler he has and what it's claimed output is? Many a time we have seen much smaller indoor units replace much larger outdoor versions.  Not knocking garn at all but just look at the Windhager thread were both Windhagers are smaller than just one of the 2 garns they replaced. 

There is no job too big that a well designed system can't handle.


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## ditchdigger (Mar 11, 2014)

OK people, first and foremost, thanks for the replies and input, at this point anything is helpful and wanted, don't feel shy to tell it like it is, or how you see it, your not going to offend or hurt my feelings at all, I like to hear it like it is, and don't leave anything out, or leave it to me to imply anything, most times I get it wrong anyhow.    

As for what I have now, I bought it on a whim and an urgent need with little background checking or asking questions, to say the least, if one can do anything wrong, I've done it more than once.    I currently own wood doctor, not pressurized, and I'll admit, for the first few years, it worked good, but burned far more wood than I ever knew anything every could, the comment about burning the forest down to keep warm, is a mild understatement.    We've had leaking issues with it, and quite frankly not wanting to offend anyone, I personally think its a waste of good metal in its design and efficiency, I won't even discuss warranty issues or lack there of, or my dealer support, nice guy, but.....

Its the second to the largest model they made, I'm told they're now a pressurized boiler, not wanting another round and looking for something better in terms of efficiency, its supposed to be around that half a million btu's mark, or so the claims go.     

We've had issues this winter with not being able to maintain boiler temps, I'm also thinking there's not a big enough fan on the unit to feed the fire and keep it burning hot enough, but with the leaks we've had, which its currently leaking now........again, I'm hoping it makes it till its spring and we can shut it off for good and replace it.    

As for the wood issue's, since this winter has set records on extended cold spells, we figured we had enough wood to last into next fall, cut, split and died, and it ate it all and we were out the middle of january, so we went down and took dead and down tree's out of the woods, and have literally shoveled those through the furnace, not sure it even slowed up long enough to breath myself, and we again ran out of wood in mid february, so back again to the woods for more, nothing ideal, just anything we could toss into the inhaling beast that might bring about some heat.    As they say, when things go wrong, they really go wrong and compound issues.   In over 40 years of heating and being around wood, I've never ran out, or even close, also never about froze to death in my own house either till this winter due to the lack of heat being produced.  

As for specs, on the current system, we have an older two story house, about 100 years old a couple thousand square feet, has been remodeled several times and isn't bad to heat, believe me, I've lived in some old drafty, two story hotels of houses before that were impossible to heat due to no insulation, this is far from it, with the old lp gas furnace, which my dad put in back in the late 80's it would take anywhere from 1000-1500 gallons of lp a winter to keep it really nice inside, some mild winters even less.     We have forced air heat in the house, and also a side arm hooked to the water heater for hot water.   With the family getting old enough to go out on their own, we will no longer heat the water in the summer with a wood boiler, before with girls especially at home, [anyone with girls knows what I mean] and the boys still at home, we seemed to go through a lot of hot water, once the girls left, I wondered if the water heater was even used on some months, but that's another story.   

My shop is a remodel in an old barn, we installed a hydraulic dooron one end, that fully opens up the whole end, 32x20 high and we bring equipment in and out all the time, we also installed in floor heat tubes in the shop, this is the first winter we had heat in it, which brings up a major issue, we want to have forced air fans on the wood boiler to bring my shop temps back up quicker, especially if we bring in cold equipment to work on, as they say a 25 ton piece of equipment coming out of -25 below zero temps a large block of ice to warm up, I want to speed that process up considerably, not something most do or even think about doing, but its what we do all winter long, work on equipment and get ready to go break it again next year in good weather working it.    My current office is about 17x17 and has in floor heat, cement block walls and the pour in insulation in the blocks. the rest of the shop has anywhere from pour in insulation in the walls to over a foot of fiberglass blow in the walls to over a foot of fiberglass batts in the ceiling, the door is the poorest insulated in the building being only 4 inches of insulation in that.    

My house is about 150 feet from the current boiler, the shop is about 40 feet, we have one inch pex insulated lines in the ground to each of them.   I'd like to put an addition on the shop that would be 32x20 with about 15 foot ceilings, in floor tubes and a full width door on one end too, and forced air heat off the boiler for that in addition to the tubes in the floor.   

I'd like to then build a building to house my heating source in, along with any water storage and some wood in as well, I'm tired of standing in a snow bank and the wind to shovel in semi loads of wood into the furnace, literally.    What that size would be is in question.     

I'd also like if possible to heat a second house, already on site, done, a newly remodeled house with a garage, and in the near future put an attached garage on my house, how or even if this is all possible, is yet to be seen, or even if it's feasible.    

The next question that comes along is going to be what's my budget............... and as stupid as it sounds, I'm not sure, I'd like to weigh options and costs first, then decide which will give me the least grief, biggest bang for my buck over the longest period of time.............

As non politically correct as it sounds, so don't shoot me, I've even considered waste oil boilers for my shop or forced air heaters to supplement heating those needs, an add on gas boiler and everything else imaginable too, and yet I'm looking at wood the hardest.      Any other questions, just ask.


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## NE WOOD BURNER (Mar 11, 2014)

ditchdigger said:


> we have one inch pex insulated lines in the ground to each of them



Do you know what brand of pipe it is?


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## ditchdigger (Mar 11, 2014)

NE WOOD BURNER said:


> Do you know what brand of pipe it is?


I'd have to go look to see if there is a brand on them, right off the top of my head, I don't recall, but its one inch green pex lines, foamed into four inch drain tile, there are no connections under ground, a continuous run for the shop, and another for the house, both come up by the owb now and two pumps at the furnace once for each line, both gruntfoss pumps.


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## NE WOOD BURNER (Mar 11, 2014)

I would suspect that your temp difference from beginning of run to end of run is too high. If you could measure that(delta T) You maybe surprised. You may not reuse that pipe on your next design if the delta T is to large.


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## ditchdigger (Mar 11, 2014)

I'll check those temps hopefully today and get back to you on it soon, anything else you might want me to check out?


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## NE WOOD BURNER (Mar 11, 2014)

That would be a good start.
pictures also are welcome here. "a picture is worth a thousand words"


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## Fred61 (Mar 11, 2014)

Tell us how your slab heat is constructed.

Edit: and how dry your original hoard of wood was.


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## flyingcow (Mar 11, 2014)

I am curious about the slab too. Insulated underneath,? perimeter insulated? If so, how much R-value?


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## Boil&Toil (Mar 11, 2014)

I seriously wonder if you'd be better off with a woodchip (not pellet) unit based on the scale alone, rather than a stickwood. Sounds like you either have or would be comfortable with the sort of equipment that might feed one, and it cuts down on wood-handling a lot. 

As has already been mentioned, any heat load can be met by combining units (and I don't know that anyone has mentioned, but it also gives you redundancy in case of a breakdown - much better to have 2/3, half or even 1/3 of your normal capacity than to be out completely.)


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## ditchdigger (Mar 11, 2014)

NE WOOD BURNER said:


> I would suspect that your temp difference from beginning of run to end of run is too high. If you could measure that(delta T) You maybe surprised. You may not reuse that pipe on your next design if the delta T is to large.



I did the temps, not sure how accurate they are, I'm thinking I need a new laser temp gun, first off we had different fittings in the mix, some brass, some galvanized and the pex coming into the furnace was too close to the furnace to get an accurate reading and the brass was on the furnace, so that wasn't accurate at all to compare to.    But the best I can deduce at the moment, is on the short run to the shop, maybe a degree or so difference from the outgoing of the furnace to the incoming into the shop, but that's the short line, and in the house run maybe a few degree's difference, but I'll admit I need to do it again with another temp gun.    In the past we had the line exposed to the snow laying on top of the ground when I had the furnace at a rental house I used to rent, all winter long and the snow never melted off it ever and when we did the comparisons back then there was no temp drop on that same short line, we just moved it to our current location.


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## ditchdigger (Mar 11, 2014)

Fred61 said:


> Tell us how your slab heat is constructed.
> 
> Edit: and how dry your original hoard of wood was.



The slab heat is constructed as follows, we used the insulation board under the concrete, the two inch stuff the concrete supply place sells to all the cement guys in the area, there is the black board all the way around the perimeter of the cement inside the building, a couple inches deeper than the insulation board under the cement.    We did a couple things different on this deal, since the concrete is pretty thick to hold up my heavy equipment, 8-12 inches, some of the thinner concrete we stapled it to the insulation board, most we tied the heat line to the rebar in the center of the concrete slab, or half way down into the concrete.    We have a service pit in the shop as well, we put in floor heat  in that too, and used insulation board all the way around the perimeter of the pit walls, so they contacted the insulation board under the floor slab.    

Since it was  a remodel job of the old barn, there is a foot cement wide slab between the heated floor slab and the concrete wall and footing, basically under my insulation in the wall of the shop, then another black insulation board between that narrow slab and the wall, when we shot floor temps this past fall, that narrow slab was the same temp as the concrete wall behind it, and the floor was up to 30 degrees warmer so I'm not thinking we're losing much heat through the walls, the snow has never melted at all on the outside of the building anywhere.


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## ditchdigger (Mar 11, 2014)

Boil&Toil said:


> I seriously wonder if you'd be better off with a woodchip (not pellet) unit based on the scale alone.
> 
> I've actually given this considerable thought, we investigated this years ago, even before we bought the current owb, but back then, there weren't many small enough for me, most were for industrial applications.
> 
> ...


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## ditchdigger (Mar 11, 2014)

Fred61 said:


> Tell us how your slab heat is constructed.
> 
> Edit: and how dry your original hoard of wood was.




My hoard was log length for years, stacked out back and two years ago we bucked it up and split it, it was either piled outside or in a small wood shed, we also bring in greener wood occasionally and mix it in as we go along.    We typically have plenty of logs on hand at all times, its just been such a hectic year we never got any more rounded up and brought home, figuring we had all summer to do so..........but I was wrong and we ran out, probably will never happen again though in my lifetime.


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## ditchdigger (Mar 11, 2014)

The shop is set up with an isolated system right now, we installed a hot water heater to use as storage, and pressurized the shop side of things, and has antifreeze in it as well, we use a plate heat exchanger to transfer the heat from the owb to the shop side of things, not sure that matters, but its what we did to help equalize the lines in the shop, the entire floor was set up on a slope towards the door and the pit floor is seven feet lower than the office.   I've had people tell me this is completely the wrong thing to do, others say its ideal and how to do it.    We set up a pump between the plate heat exchanger and the water heater, we set the thermostat on the water heater to start and stop the pump, the thermostat is set at 120 degree's or what the temp going into the floor is set for, there is no mixing valves anywhere, we took them out of the equation for the in floor heat, again this is a subject of discussion among some plumbers as to if this is the way to do it or not.


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## 711mhw (Mar 11, 2014)

Like someone else mentioned, have you thought dividing up your load with several (smaller) units? I know my Wood Gun throws off a good bit of heat, they all must, and to put all that heat in an out building seems like it would make much more sense in a bsmt. & the shop. It might make sense dollar wise also, the price of a 500,000 btu = how many 100k units? This also spreads out your wood loading to several locations which may or may not be a good thing. If you have guy's in the shop, they can take care of that one, etc. I think a* real good* heat load figure is the best place to start. Good luck & welcome to Hearth.com


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## NE WOOD BURNER (Mar 11, 2014)

ditchdigger said:


> if anyone can balance the load for me, so when its frigid out, I'm not working or sleeping in the cold, or blowing off hot water in the milder temps in order to keep the boiler fired.


ditchdigger: This is the benefit of Batch burning to thermal storage. 
some burn to storage and heat from storage and others hook in series so the storage is charged after or during the heat load of the structure. if you go to youtube and look up munchkin gas boilers they have a great explanation of thermal storage using a high efficiency boiler. they use the video to explain the need for their Boiler buddy tanks.
Sounds like your Underground piping is performing well so that rules that out.
one thing to keep in mind is that your OWB most likely has a tremendous amount of standby heat loss. This winter was cold so your heat load and standby losses where increased.
the advantage to thermal storage in the heated structure is that your standby loss will be lost to what you want to heat.


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## ditchdigger (Mar 12, 2014)

711mhw said:


> Like someone else mentioned, have you thought dividing up your load with several (smaller) units? I know my Wood Gun throws off a good bit of heat, they all must, and to put all that heat in an out building seems like it would make much more sense in a bsmt. & the sh
> 
> Yes we've thought about dividing up the load into smaller units, but this gets complicated if I can attempt to explain it right.    I grew up with a wood furnace in the house basement, this house in fact I now own, and I don't want the wood or furnace in the basement again, I'd rather have it in a separate building of its own outside somewhere, to eliminate the smoke and debris from the house, along with the wood based critters.
> 
> ...


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## ditchdigger (Mar 12, 2014)

Sorry about the format, I haven't quite figured out how to work this system yet and do the replies and get just the quote in the blue box each and every time


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## NE WOOD BURNER (Mar 12, 2014)

house 1: 2500 S.F. /FHA and side arm DHW /annual LP usage was 1500 gallons
garage 1: TBD

house 2: ?
garage 2: ?

Shop: in floor radiant  with a plate exchanger

So break it down into pieces. heat loss calculation/analysis of individual structures. this will determine your total heat load.
The main problem I see is the shop with 32x20 full open door. you wont recover fast enough with in floor for immediate comfort.
Growing up in the garage environment the emphasis on timing of repairs in the winter was critical to save heat. Bring in equipment early as possible and heat when you are not in the garage. can the door be partial opened or just all or nothing? We had FHA waste oil burner and a wood stove. Over head doors only opened to height we absolutely needed. Tough to police with employees.


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## ditchdigger (Mar 12, 2014)

House two, has in floor heat in the new portion of basement, never hooked up yet, insulated and cemented the same it is about 700 square feet with the in floor and the old portion was just concrete, roughly another 700 feet, the whole house is forced air with a gas furnace.     Garage two is also done new with in floor heat, fully insulated and never hooked up the in floor heat yet, insulated garage doors and it by itself keeps pretty warm, even with the frigid weather this winter, it only ever dipped a few times below freezing in the garage, square footage is roughly 700 feet, the whole house has new windows, all new insulation in the walls, under the siding and over a foot in the attic, the basement walls are also insulated on the outside with insulation board.    

I forgot to mention, all the concrete floors with tubes in them, have a vapor barrier under the concrete, and before anything was done, more drain tile installed than anywhere on the planet per square foot to eliminate water issues ever under or around the floors.

As for the shop, the door hinges at the top, one piece opens up, we only open it far enough to get what we need out and back in, but as the door opens, it swings open so the crack is fully to the top and gets wider as it opens.   Its not the amount we open it, its the amount of time its open for and how often we have to open it is what gets us, we try to do it at the end of the day so it has all night to heat back up again.    Now for the subject of in floor radiant heat, I've been told it yields roughly 25 btu's per square foot of floor space, no matter how you go about it, or roughly 60,000 btu's in the main shop from the floor heat alone, has anyone else used this same figure per square foot, and if not, what is the amount to use?

Anyone have an opinion on a Royal pressurized boiler, are they somewhat better as far as efficiency goes, or just about like all the rest the owb's out there?    Anyone with experience with them, had one at one time or still do?


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## NE WOOD BURNER (Mar 12, 2014)

so in house1 and house2 is there room to install a water storage tank inside the structures?
house1 I assume is your dwelling. is there away to install an indoor boiler in there?

Garage door: that a tough one. only thing that comes to mind for that is a bellow for the top portion that will open with the door and seal out the wind. and possibly a hanging plastic curtain similar to what you would find in a walk in cooler. That size door makes a big hole.

FHA works best with higher temps. so the theory is to utilize low temp emitters(radiant) allowing you to maximize time between burn times.

Thinking out loud here:
thermal storage in house 1 and 2 heat from storage.  possibly install an indoor unit in house 1 convenient for first batch in morning giving you a jump on your next batch in a Garn type boiler in or near the shop.

now if your convinced that you want pressurized from your experience with your OWB I would reconsider for sake of looking at a Garn and the proven track record I read about here.

if you insist on pressurized than I would install a gasser in an outbuilding near your existing setup and have divorced storage in the structures.

just thinking out loud-many ways to skin the cat here. the difference here is the concept of batch burning to storage rather than a one fire keep it going method.


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## Vizsla (Mar 12, 2014)

I like this guys attitude, not afraid to get dirty and get in it to get it done.

I'm gonna go out on a limb here and guess that this large load being fed thru just 1" green pex( which is usually .876" ID) and only seeing a degree difference. Means that water is a Flyin' in that pex. A job this size should have a minimum of 1.25"ID to deliver this large of a load. So the current measurements aren't much use. Just out of curiosity what is the depth of the pipe and does it hold snow or frost like the rest of the yard? I seen pictures of some pex that looked like it was sand blasted or melted from the inside out. Giant pump , small pex, lots of bad stuff.

I will second the chip boiler just for ease of feeding and ease of fuel source. I mean what tree arborist doesn't dump free loads of chips.


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## Boil&Toil (Mar 12, 2014)

I'd definitely think about radiant ceiling/upper walls AS WELL  AS the radiant floor and fan-coil-units for the shop with the huge door. You can (guessing) probably run through the fan-coils and then into the radiant. Lower walls only get nominated if nobody's going to drill anything into them. Upper walls and ceiling get a stencil along the lines of "radiant heat loops - do not drill, dummy!" every 4 feet or so d;^) I know in *my *case that's just me reminding myself not to be a dummy, not calling anybody else names...


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## ditchdigger (Mar 12, 2014)

Depth of the pipe in the ground, my trencher we used digs six feet deep, so I'd guess its slightly over five and half feet deep, buried with the water lines we put in new at the same time, the only place its shallow is by the boiler where it comes to the surface and hooks to the boiler, nothing ever melts anywhere near it, and this winter, I'm guessing its encased in frost by the water temps I'm seeing coming out of my water lines in the same trench.

As for the houses, any storage that can go through a 28 inch wide door can go into the basement of my house, or house number one, and house number two has three foot door ways in it.    As for storage, anything can be done, as for the boiler, meaning wood in the basement, not going to happen, if I want to remain married, not sure I can afford a divorce, that would pretty much kill my budget for a new furnace for decades     As for house number two, storage isn't a problem, but a  boiler in the basement won't happen either, I don't want to be disowned by my mother any time soon.

Radiant tubes in the walls and ceiling, that's a new one for me, how do you go about that, now that the ceiling and walls are insulated and tinned, have all my electric lines run and all my lights in place?     Are you talking stringing up water pex lines on the walls to allow them to radiate heat off as is?

As for chip boilers, anyone know anything about them, have one or been around one?    Any idea's how to size one, there's only one I know of anywhere near me, I'm thinking its a million btu's and he has major storage, and far more heating needs than I do.


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## Boil&Toil (Mar 12, 2014)

Given that it's finished and that it's a shop, probably just put it on the surface with heat transfer plates and leave it exposed.

In new construction or remodelling, you normally put it on top of/behind the drywall. You can run it a bit hotter than floors without making anyone uncomfortable, and it puts out roughly the same BTUs/hr per square foot - so added square feet ups your BTUs/hr. 

For chip boilers, Lopper-Drummer is one brand that I've seen mentioned; I have not met one in person. 42-460 KW (142,000 - 1.5million BTUs/hr)

http://www.loppernorthamerica.com/turner-chippellet-boiler.html

Someone on here in Canada has one of their stickwood units (without the auto-loader option).

I passed on the option to buy a chip-boiler of unknown make or efficiency a while back, primarily because it was a "hurry up and get the heavy thing out of here" sale after a death - had been used for greenhouse heat - and I wasn't really ready for it.


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## 711mhw (Mar 12, 2014)

Look around here, I think that there is a guy in VA that heats a farm operation with wood chips.Can't remember his name. I'll go look, but he might be able to help some.

edit; fuelfarmer


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## NE WOOD BURNER (Mar 13, 2014)

ditchdigger said:


> I've been told it yields roughly 25 btu's per square foot of floor space, no matter how you go about it



do you know the design temperature that was used for this output determination?


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## ditchdigger (Mar 13, 2014)

Boil and Toil, what are heat transfer plates?    I've never heard of anyone ever doing this before so I'm sorry I'm asking stupid questions, also how do you fasten the tubes to the wall, without damaging them, do they make an insulated holder of some sort that you can clamp the line in, and screw that to the wall.   I know they make things to hold the lines so you can install them on basement ceilings to direct the heat up through the floor above.   

711 mhw  I'll check that out and see if I can get a personal message off to him, thanks for the information.   

I'm sure progress has been made in the development of a smaller chip boiler in the last few years, and I've not talked to anyone who has a newer version, but all the older chip boilers were a challenge to size for heating demands, because every set number of minutes they'd have to fire in order to keep the flame going so they would start back up again.


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## ditchdigger (Mar 13, 2014)

NE WOOD BURNER, no I don't know the design temps used, all I was told by two of the local plumbers, when it was 50 below out for weeks on end that part of my heating problem was in floor heat puts out only 25 btu's per square foot, and I needed additional heat added to the shop if I ever expected to keep it warm enough to work in [they were trying to sell me lp ceiling radiant heat tubes at the time].     We started the shop over five years ago now, finally got it done, and I can't remember what I was told to expect out of the in floor heat back when it was discussed that long ago, nobody in the family could either.    I was wondering what everyone else used for btu's per square foot, I've looked on the internet and couldn't find anything practical I could apply to a shop setting.


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## Karl_northwind (Mar 13, 2014)

ditchdigger said:


> Depth of the pipe in the ground, my trencher we used digs six feet deep, so I'd guess its slightly over five and half feet deep, buried with the water lines we put in new at the same time, the only place its shallow is by the boiler where it comes to the surface and hooks to the boiler, nothing ever melts anywhere near it, and this winter, I'm guessing its encased in frost by the water temps I'm seeing coming out of my water lines in the same trench.
> 
> As for the houses, any storage that can go through a 28 inch wide door can go into the basement of my house, or house number one, and house number two has three foot door ways in it.    As for storage, anything can be done, as for the boiler, meaning wood in the basement, not going to happen, if I want to remain married, not sure I can afford a divorce, that would pretty much kill my budget for a new furnace for decades     As for house number two, storage isn't a problem, but a  boiler in the basement won't happen either, I don't want to be disowned by my mother any time soon.
> 
> ...



Heizomat will be bringing in boilers this year; down to 200,000 btu.  the RHK series will burn nearly anything you can feed in.  only no cordwood.  chips, sawdust, straw, corn stover, etc.  

not cheap, but no screwing around either.  they've been building them for 30 years. Kinda like the Garn Philosophy: big solid steel heavy, etc. 
Karl


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## NE WOOD BURNER (Mar 13, 2014)

ditchdigger said:


> no I don't know the design temps used



The reason for the question is that most BTU outputs are based on a certain water temperature. You would make a reduction based on your design temp available.

so if design temp is 180 and you have 140 it effects the amount of BTUs out. obviously if you add more tubes you increase your btu output, wall and ceiling idea is a good one.

We have lp radiant panels in ceiling in a very large shop ~9000 s.f. and FHA waste oil burners. The waste oil does the Lion's share and the ceiling  panels make it comfortable they are hung at 22' ceiling is 25'. you wear at hat so you don't get sun burn on the dome. It does warm the equipment nicely.

I would think you could estimate the length of tubing and use a standard btu rating for the brand of pex(adjusting for water design temp.) to determine the output.

I am currently sizing cast iron radiators for my residential install in the same fashion.


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## Boil&Toil (Mar 13, 2014)

ditchdigger said:


> Boil and Toil, what are heat transfer plates?    I've never heard of anyone ever doing this before so I'm sorry I'm asking stupid questions, also how do you fasten the tubes to the wall, without damaging them, do they make an insulated holder of some sort that you can clamp the line in, and screw that to the wall.   I know they make things to hold the lines so you can install them on basement ceilings to direct the heat up through the floor above.



Most PEX design guides come out closer to 45 btu/sq ft - might depend on your tubing spacing/size. *Linear* foot-wise, ~25 btu/ft for 1/2" diameter tubing, which is normally spaced closer than a foot apart. What's your floor *surface* temperature when running? I see you are running 120F water into it, but what 's the surface at - if it's not uncomfortable, turn up what you are sending it until it is, then turn it down a touch. The other question would be the *return* water temperature - if there's a huge drop (like it's below 100F), more pump might help. Floors are somewhat limited since they get uncomfortable if too hot - walls and ceilings can be run hotter if you have the water temperature available. The ability to work with low temperature water is one thing that makes radiant good for use with storage, but non-floor radiant can use hotter water if you need to and have it (and still does work at lower output with low temperature water.)

Heat transfer plates, or spreaders are the same things used on wood floors - aluminum channels, ranging from expensive extrusions down to aluminum flashing with a "u" pressed into it. Aside from holding the tube, they conduct the heat out across a larger area of ceiling/wall/floor. I'm making the assumption that in the shop, you won't have an issue with being able to see these. In the house, nobody expects to get away with that and remain married, so they go inside the walls/ceiling/floor, as they would if put in when the shop was being built. Rather than "directing" the heat, they spread it over a larger area.










Contemplating really out there ideas, you could possibly toss a greenhouse-type structure beyond your big door to serve as a machine-sized airlock, but you still have (as you originally noted) the large mass of cold metal to heat when bringing one in, so it might not make enough difference to be worth the bother.

As for design help (just beware the our-brand-is-best-ism they all have, especially considering you already have whatever you have in the floor, and can't change that much):
http://0323c7c.netsolhost.com/docs/PEXDesApplGuide.pdf

http://www.radiantcompany.com/manual/manual.pdf

http://www.roth-usa.com/PDF_Download_Files/Install_radiant_heating_system.pdf


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## ditchdigger (Mar 13, 2014)

As for the floor temps, earlier this past fall when things were actually working like they should, we had floor temps in the upper 70's and low 80's, and it was hot in the shop, water temps were good too in the water heater and we could keep that 120is degree heat in there as well, then the return line temps were about a 15-20 degree's less than ingoing temps, then it got cold, really cold in a short amount of time, and things went bad in a hurry.   In the most frigid temps, we had an impossible time to even get to or stay at that 120 mark in the water heater, and they went downhill from there, we even slowed the transfer rate more still by slowing the pump on the furnace and also the at the plate heat exchanger to keep from freezing in the house on the most brutal days, and we added the knipco heater in the shop to help that out, and as the temps lowered in the water heater, the temp spread increased in the floor, from the ingoing to outgoing temps, and then it never warmed up at all outside, and it was a losing battle from then on all winter long.    Couple owb water leaks, snowy covered wood, wet wood, and some undesirable wood and things just kept getting worse, the only bright spot is, spring's got to be near soon, so I can end the misery of this winter, and bide time to decide what to do for next winter.   

I'm told a cold start up for a floor is nearly impossible to get up to temp in the middle of winter, it will take all the heat an owb will put out, I've been doing that all winter long, and losing the battle, the time between cold snaps this winter were hours, not days or weeks, and once we cooled down the floor to rob heat off that to keep the house good, we never gained back what we took away from the shop, even today, my temps in the shop are not hot enough still to get back to 120 in the water heater, and by now, I'll be honest and tell you all, I've got a severe attitude problem and just gave up for this winter, and we're using a knipco in the shop.   

Thanks for the information on the wood chip boilers, most of the makes posted here I'd never heard of, same goes for wood gaser units either.


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## NE WOOD BURNER (Mar 13, 2014)

ditchdigger said:


> Thanks for the information on the wood chip boilers, most of the makes posted here I'd never heard of, same goes for wood gaser units either



This site has been a real eye opener for me as well. What is interesting for me is that even if a person hasn't purchased a top of line unit the add ons and practical experience here usually will get the person heating as efficient as possible.

from your last post sounds like your return water temp was very low to the OWB. The manuals and advise here is to have a valve that controls the temp of the return water to the gasser boiler to avoid premature failure. FYI 

I visited a shop that routinely brought in track vehicles they would run them in on rubber mats on top of foam board insulation to isolate the heat draw from the cold iron. they had in floor tubes as well. not sure if it helped. I will have to visit again to see if they had good results.

The 120 degree supply temp is very low directly from your boiler. FHA in house must have been cool.

I would still keep in mind possibly installing some low temp heat emitters in house1 and have divorced thermal storage inside there. House 2 sounds like you should be good with your in floor system but certainly thermal storage there wouldn't hurt either. my thinking on this is that once the tanks are to temp your boiler would serve the garage and house would maintain on the storage going from say 180-120 before recharge. in the garage you could stand up 1000 gallon lp tanks for thermal storage. so four tanks from the scrap yard would be $2000. so now most of your stand by loss will be lost to the structures. how you heat the storage: I like the idea of two units since you have the houses. one unit could be chip and the other cordwood even.

I was chatting with an engineer at work today regarding the garage heat situation. he thought an easy solution would be to use concrete curing blankets on your slab when you need to open the doors. I think that is a good idea especially if you could also use them in your business.


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## Boil&Toil (Mar 13, 2014)

ditchdigger said:


> As for the floor temps, earlier this past fall when things were actually working like they should, we had floor temps in the upper 70's and low 80's, and it was hot in the shop, water temps were good too in the water heater and we could keep that 120is degree heat in there as well, then the return line temps were about a 15-20 degree's less than ingoing temps, then it got cold, really cold in a short amount of time, and things went bad in a hurry. In the most frigid temps, we had an impossible time to even get to or stay at that 120 mark in the water heater, and they went downhill from there, we even slowed the transfer rate more still by slowing the pump on the furnace and also the at the plate heat exchanger to keep from freezing in the house on the most brutal days, and we added the knipco heater in the shop to help that out, and as the temps lowered in the water heater, the temp spread increased in the floor, from the ingoing to outgoing temps, and then it never warmed up at all outside, and it was a losing battle from then on all winter



You *can* heat up a cold slab in the winter, but you can't heat a slab if you don't have adequate heat - and this tale basically says you lack adequate BTUs for cold weather (yes, I think you are aware of that.) NE WoodBurner, I'm pretty sure the 120F is what's feeding his floor, but he couldn't maintain that without freezing his house, so he turned it down. He's generating that from a heat exchanger off the OWB, it's not the OWB output temp directly. Two issues - insufficient heat exchange capacity if not able to maintain 120F with more temp in the boiler, and then turning it down to maintain heat in the house - which basically says insufficient BTUs input. It's a pretty typical temperature to heat a floor with, but going down from there was not going to have good results - could have tied in an oil-fired (waitaminnit! house 2 has GAS heat - you have GAS! Use GAS! (unless you mean propane)) waterheater when the system couldn't maintain that, or do what was done with a different type of heater.

As for stressing about the door openings, this jarred loose a tid-bit a guy who used to do practical solar thermal worked out.
http://www.iedu.com/Solar/Panels/ skip down to heat storage discussion if you don't want to read the rest, and to explanation if you're really in  hurry (or don't go at all). He basically worked out that for a 10 ft high shop, less than a tenth of an inch of concrete stored enough energy to re-heat all the air in the shop when the door was opened. It's the 10 tons of -20F steel you need to worry about.


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## NE WOOD BURNER (Mar 13, 2014)

Boil and toil: That is a good read I read the thermal storage portion. I do not disagree with his logic. But I think that is derived from a warm slab heating the air in the shop. If the floor is heated at 120 water in. assuming the floor has lost the thermal storage with the extended door open times and cold machinery. the response time to heat floor and then the air to recover a working heat range of 50 or above would require a large BTU heat source. the blanket idea would keep much of the slab heat in storage thus helping the recovery time(in theory). there is no replacement for displacement! more btus certainly!

 I do agree that with his current system a supplemental boiler would be needed.

kinda the reason I was thinking two boilers one could feed the structure load and excess to storage and the other could just run to heat the storage.
I did forget about the heat exchanger and was thinking he had only 120 from the source.
He will need big btus for garage heat load and that will aid in the recharge of the house thermal storage as well in the evening or when he is not in the shop.


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## Boil&Toil (Mar 13, 2014)

Yes, Morris does point out that average BTUs in must meet or exceed average BTUs out to make it work; and that's the main issue here.


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## NE WOOD BURNER (Mar 13, 2014)

I don't recall what model Wood doctor he had to look up the max BTU output. just for curiosity sake as it is be replaced anyway.


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## NE WOOD BURNER (Mar 13, 2014)

Boil&Toil said:


> Yes, Morris does point out that average BTUs in must meet or exceed average BTUs out to make it work; and that's the main issue here.



yes that is the main issue.

So now we need to determine the BTU needed for the existing heat load and proposed heat load. I would think someone here would recommend an output for house1 and house2. and maybe one could take a stab at the garage.

in my mind:I am thinking a building at the location of the OWB to house a GARN 2000 since he has the exchanger in place leaving room for another garn 2000 if he likes the function of it. this way all thermal storage and boiler are outside the houses.

if second one is not desired utilize divorced storage in house 1 and 2 and extend burn times from one effectively having 4000 gallons of thermal storage.  

if it don't cut it then add a pressurized gasser in the boiler building to augment and have backup.

certainly need to get wood now for next year though.


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## ditchdigger (Mar 13, 2014)

My wood doctor is the second to the largest one they make, supposed to be at or near 490,000 btu's, now that said, I'm not thinking it'll do anywhere near that much on its best day, with ideal wood and conditions, factor in lousy, wet, snow covered, and the worst conditions possible, maybe on its best day, half of that, when we run the numbers of the buildings and house, compare that to lp gas of before, factor in a frigid winter and the heat rise we needed this winter, I"m not thinking myself, we had even 250,000 btu's being produced, far more used and needed and no time to gain back any heat lost, add in heat loss of various sorts, and now I'm wonder just how big is big enough for the future?     

The more I look at it, I don't think there's any way I'll ever get by with one boiler, as for the furnace in house number two, its two years newer than the one in mine, we figured it would have died a couple years ago, and the whole idea of heating outside the house in the first place, was so I didn't have to replace that furnace with a new one, not sure it's going to be considered  a backup even on a good day.      

I've been on the phone today with several chip boiler makers, some are interesting to me, others maybe not, I'll have to give it some serious thought on going that route, we've had some discussion on my end and maybe its not ideal, but a chip boiler running almost 24/7 fall till spring, heating storage, and a second larger firewood boiler to kick in with colder temps, have it plumbed to kick it online as needed and shut it off when not.    I'm not liking the cost end of things, but after doing some math on the possible what if scenario of costs at lp gas, in a few years of heating costs, maybe its not so bad.    

As for the discussion, keep it coming, the more we discuss the more I learn, and learning is never a bad thing, and its sure cheaper than learning by doing, so again thanks people.


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## NE WOOD BURNER (Mar 13, 2014)

Would you know how many cords you have burned this year?

are you buying wood or do you have a free source?


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## Boil&Toil (Mar 13, 2014)

NE WOOD BURNER said:


> So now we need to determine the BTU needed for the existing heat load and proposed heat load. I would think someone here would recommend an output for house1 and house2. and maybe one could take a stab at the garage.



Crud, looks like Gas means LP, not NG - oh, well.

Anyway, house 2 should be trivial to figure out if it's using LP now - how many gallons of LP does it use over some time period, grab the preliminary climate report for the nearest airport, how many HDD were there over that period, a little math and it falls right out, plus a fudge-factor for the addition it's not quite up to heating. Or LP for a year, and as below.

House 1 was 1500 gallons LP, ~138,750,000 BTUs/year - just need to know the annual HDD to turn that into a number. Don't know where you are relative to Ames and not going to try, but Ames was the first place in Iowa that handed me a number I can use - looks like 6500 HDD on average = so about 889 BTU/Hr/DegreeF. 78,232 Btu/hr for -20F design temp (68 inside) adjust as needed if those don't suit (add 889 for every degree lower you want to design for, and/or degree higher inside to keep the spouse happy.)

Shop - don't know the size, other than it's 32 feet wide and has a door 20 feet high at one end, so it's huge. Insulation is variable and includes "pour into block" which I consider terrible insulation (the webs of the concrete block are utterly uninsulated, the wall as a whole is very poorly insulated - I don't have a hard number for it, but I lived with one and it bled heat) - that would benefit a great deal from even an inch of styrofoam or sprayfoam over it (and that should tell you something, as that's only R5.)  If the big door is insulated with 4" of rigid foam, it's probably a lot better insulated than any of that block wall with pour-in, at about R20-28 depending on foam type. It's a barn, it will be longer than it is wide at the end, so there are a LOT of square feet and cubic feet, and the best they are insulated is a foot (perhaps more in places) of fiberglass at R-38 - and a little secret about fiberglass is that the insulation value is reduced in very cold temperatures, since it allows air to move much more than cellulose (which actually improves, very slightly, as it get colder.) So it's an unspecified but probably LARGE number of BTUs/hr if a half-million (or even quarter-million, as discounted) OWB can't keep an 80,000 BTU house and it heated, before we add other loads. Knowing how much (diesel?) is used to heat it this winter would help to establish some number, though if wood is also being burned that's harder to be sure about - it at least helps set some lower bounds.

Incidentally, I'm following pretty much the same placement logic without even getting the insurance company involved (though I am considering them) - My plan is that the boiler barn is of fire-resistant construction and far enough from other buildings that it can turn into an inferno and not set anything else on fire, without being absurdly far so as to make for very long lines. It might also get some (minimal, we're on a well) sprinkler coverage for the what-if's.


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## ditchdigger (Mar 14, 2014)

First off, what's HDD??    Next the shop is 80 feet long with a 20 foot ceiling, the walls in it are irregular in shape, as compared to the outside walls and range from 10 inches at the least of blow in fiberglass to over two feet in places, we looked at spray foaming it, but while doing the remodel, we gave up trying to figure out to make it work, its a long complicated story as to how we had to go about the process, so in the end we blew fiberglass into the cavity once the whole job was done.    

Your right about air movement through fiberglass though, we salvaged used tin for the inside liner of the shop and later found out that even though it looked pretty good, there were excess holes in the tin from the last building it was nailed to, that when the wind blew over 50mph, if you held tissue paper up next to some of the holes, you could see slight movement some of the time, never gave that a thought when we decided to use the tin.    I can't argue at all with the insulation in the cement block, I might even add some more to that and say it plain sucks and totally worthless, but I didn't do any of that, it was done decades before my time and now we're deciding the best way to go about to solve that problem, which looks like it'll new studs and tin on the outside of the office.    

I'll never argue with spray foam being better at insulating on an inch by inch comparison to fiberglass, but the downside of spray foaming is, if you ever want to change or remodel the structure, you now have a mess to contend with and its almost impossible to scrap or peel it off, yes it can be done, but not near as easy as stripping fiberglass bat's out of walls and around electric wires and having studs and things still usable.


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## ditchdigger (Mar 14, 2014)

So what's the figure then if its 40-60 below outside and the spouse likes it 75-78 inside months on end then with little if any let up in the weather, much like this winter, keeping in mind, the warmest room in the house has the thermostat in it??      Then calculate that same outside temp for the shop, and we're trying to warm it to 60 inside the shop, near 70 in the office, again months on end and next do you consider wind chill factors, or basic air temps into your equation?   I've been told its just air temps, and if that's the case, you'd better lower that to your 20 below outside temp.


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## Boil&Toil (Mar 14, 2014)

HDD are Heating Degree Days (as opposed to Cooling Degree Days and various Degree Days for crops).

Based on actual temperature, not wind chill. Wind Chill is for people, not structures (though a leaky structure has issues with wind.) You might want to hire a youngster and give him/her a tube of caulk (or 24) and a mission to plug the holes in the inside shop tin this summer. Aside from getting a breeze through, you're probably also getting moisture out of the shop building up in the blow-in, if there is no vapor barrier other than the hole-y tin. Of course, if your walls are tin, you don't really need heat spreaders if you add more PEX to them...

If your actual temperatures outside are -40, for house 1 you add 20 x 889 to the -20 figure I used. If the spousal comfort zone is 78, you add 10 x 889 as well. But that might be factored in if the 1500 gallon figure was with the house already at 78, so...it's a game of guesstimates, and we simply try to make the best guesstimate possible based on what we know.

For the shop, you add up what you have, to the extent that you can guesstimate it. You have 2560 square feet of ceiling and floor, respectively, if the building is 80 feet long and 32 feet wide. The door and opposite end wall are 640 square feet each. The sidewalls are 1600 square feet each. If your actual exterior is -20F and you desired interior is 60F, your difference is 80F

R values are hr x sqft x DegreeF/BTU. You have square feet and a temperature difference, so work though the R-value of each part and you end up with BTU/hr for your design temperature difference. Don't forget the windows, if any (assume R1 if you don't know for an old window, up to R3+ for non-absurd new double-pane Low-e, and as much as R10 (for a few years) from the most absurd new double-pane with exotic gas fill that leaks out over a few years...As you might guess from my description, I didn't see the payback on the most fancy ones.

If the big door was insulated R1 (essentially uninsulated) it would take 640*80 BTU/hr to heat. If it's R20, it only takes (640 x 80) / 20 BTU/hr to heat. Everything else works the same way - so many square feet at such an R value = so many BTUs/hr at an 80F differential - 90F differential for the office. Add them all up and you have the building, to the extent that the estimates are accurate. The only oddball is that the floor normally won't see the same temperature differential, as the ground under it won't be -20F - while the slab is hottish from in-slab heat, if the edges are well-insulated the temperature under the slab should remain above freezing, so it might be more of a 50-60 degree differential if it's heated to 80-90.

If the vermiculite-filled (the usual for old pour-in)  block wall portions are 8" block, they are probably R-3 to R-6, so adding something on the outside of those would certainly help.


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## arbutus (Mar 14, 2014)

HDD is heating degree days, which can be used to give you an annual estimated heating requirement, so that you can figure out annual operating costs and payback for different fuels and system types over the life of the system.

Use actual outdoor temperature for heat loss calculations.  Your internal temperature requirements, 78F for a portion of the house, 72F for another portion, 70 for part of the shop, 60 elsewhere, get taken into account with a detailed heat loss calculation.  Air infiltration at different rates in your different areas will also get taken into account with the heat loss calculation.

Uponor's Complete Design Assistance Manual has a good section with examples on performing a heat loss calculation.  Zurn also has a good radiant design manual with examples.


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## ditchdigger (Mar 14, 2014)

Boil and Toil, I've got to reread this several times, and get some help to "think" through this some more, but thanks for putting it plainly so I can understand it.    Some variables in the equation, the door on the shop is insulated, we put five and half inches of fiberglass bats to fill the four inch gap, mainly so it filled the ridges in the tin, and even though we had it separated in five foot tall increments, we wanted them to hold in place, and hopefully not settle over time.     There are two double pained windows in the door, small basement windows so we could look out to see if anything was in front of the door before someone opened it, not my idea, but I kept the better half happy with two windows.     Only one other window in the whole shop, haven't insulated over it yet because we might install a waste oil burner and use the window for a chimney pipe to go through, its about 2 foot square and single pain, as for the new gas filled one's, I laughed when I read your comment, I agree totally, also seen the double pain windows on a new house leak and get moisture in them and on a frigid night, freeze and break the glass, on all the windows on one side of the house, I'm also told the warranty didn't cover it, imagine that.       

The lp gas estimate was done long before my wife moved into the house, back then 68 was considered a great temp and sometimes cooler at night, I'd have no idea what it would take to heat with lp gas this winter to the upper 70's, a total guess on my part, but somewhere over 2000 gallons at a minimum I'd think.   

No vapor barrier in the shop anywhere, wouldn't have done any good anyhow, between nails off the old roof, and all the construction we did to get the remodel done, there were nails and screws everywhere and other than make one feel good to do the vapor barrier, it would be as hole-y as the tin or worse.    The old concrete block wall runs up about 10 feet up on the side walls, and no matter what anyone would do concrete is porous and cement blocks are worse in my opinion, looking back I should have had someone spray foam a portion of the walls on the inside before we were done but then thinking, there's no way to have sealed all the cement block up anyhow, we might have eliminated a portion of the blocks, but never them all.    I'll have to ask again if anyone here wants to do the caulk gun idea, it didn't go over big when I asked the last time though, the reply I probably can't print here if that tells you anything.   

Two walk doors to the building, with only two inches of insulation in them, the rest we put 10 inches of fiberglass bats over for the winter and osb'd them up on the inside.   

Something most don't even think of, and I totally forgot to mention, we have fans in the shop, and when we're welding or running diesel engines, we turn the air over and vent the smoke, how often, depends on what we're doing, maybe run the fans a total of a couple hours a week, and no I can't tell you the cfm's of the fans, standard old barn fans, we only run one, also do this if we're changing machines and going in and out with equipment, guess you could call it a hazard of the trade.    

Next question asked a while back and I forgot to answer, firewood is free, but not to cut it down, work it up, and bring it home and prepare it to go into the furnace.   How much we burned, or usually burn, a total guess on my part, but we figured in the area of 20-30 cords of firewood per year, but that's a guess at best, we pile it up as we cut and split it, shove it up with skid steers and have piles all over the place and in one shed, can't even begin to guess how many semi loads of logs we've used this year, we're always adding and using off the piles as winter goes along.   When we used to live on another place, we did all the processing here and loaded it up and hauled it with a semi to the house we lived in, back then we burned 8-10 24 foot semi end dumps a year and I'd have to remeasure the trailer again to figure cords, its been too many years since I had that figure and I've lost it to CRS over time.   

The sidewalls in the shop are not straight up, there is a knee brace towards the top, for two reasons, one to have a straight wall to tin and second, to use for strength for the roof and false rafter we installed, so the whole shop wall is 23 feet on both sides, for a 20 foot ceiling height, and the floor is sloped in the shop, so its a foot taller on one end than the other, not sure how to figure that in, other than 23.5 feet of sidewalls.


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## ditchdigger (Mar 15, 2014)

Boil and Toil, I'm not getting how you came up with your numbers, I looked on the web, and took some of the nearest airports to me for the HDD and came up with 12850 for the heating season, I added up the HDD for each month for the desired temp I wanted for the house, and added all the months we'd heat the house and came up with 12850, did the same thing for the shop and came up with 9083 for the heating season, haven't done the office yet, but is that right first off, and if so, how did you convert that into a number for btu's per hour, could my numbers be correct, I'm a lot further north than ames, but twice as many HDD days in a heating season??


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## Floydian (Mar 15, 2014)

Good morning,

Take a look at this https://www2.iccsafe.org/states/virginia/plumbing/pdfs/appendix d_degree day and design temperatures.pdf for avg annual HDDs and design temps for a few cities in Iowa. Doesn't look like that has any city data for northern parts of your state but Sioux Falls, SD is listed at 7,839 HDD with a design day temp of -11.

Noah


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## Boil&Toil (Mar 15, 2014)

How I get my numbers: look up HDD (you pretty much HAVE to be doing that wrong to get 12,000+ in the lower 48.) There are a few parts of northern North Dakota, Minnesota and Maine that exceed 10,000.

http://www.iowaagriculture.gov/climatology/weatherDistricts/2013/pmstable201305.pdf

So you might have 8000, at most. 7788 average for north-central. They do NOT change per structure - it's based on the temperature outside.

To figure the heat loss of a structure where you know the fuel burn, but have no idea what the insulation values are (which is what I used them for): Multiply by 24 hours in a day to get degree-hours. 186,912 (for 7788 HDD)

Fuel input - 1500 gallons of LP, 91,500 Btus/gallon (I used a slightly higher figure before from faulty memory; this time I looked it up.) 137,250,000 BTUs

137,250,000 BTUs input. Divide by degree-hours (186912) to get BTUs/hr degreeF (734 with these inputs) 

Multiply by design temperature difference (inside to outside) to get design maximum BTUs/hr for that structure.

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Where you know the insulation values and square feet of each insulation value, you simply add those up to get the BTU/hr  degreeF figure, and then multiply by design temperature difference to get BTUs/hr. Sometimes it's educational to apply the above technique to see if what you think the insulation values are matches what your fuel burn is. 

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You can successively improve estimates by taking into account thermal efficiency of the furnace/boiler, etc.


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## ditchdigger (Mar 16, 2014)

Questions, I looked up on the web www.degreeday.net and they had this years data for airports that were current, and closer to me, now I scanned through this data and they had a base temp on there at 65 degree's, I took the month's I'd heat and added them up, then switched the 65 to a number of 77 for the house, which raised my HDD's up to the number I got before, might be different than how Boil and Toil did it, but I also assumed I'd used more than 2000 gallons of lp gas year too.     The data that's been posted was from very mild winters, of 2006 or last winter, this had data from this winter and I took march, april and may from 2013 and came up with the larger number.    If this is wrong, help to explain how it's wrong, this winter kicked my butt and I wanted something much more accurate than averages.   

Next question is that's converted into btu's per hour considering the furnace runs nonstop, correct?    So if it cycles on and off and you have people coming and going, etc, etc, and lets say for example wind does affect my house and shop, how many more btu's does it take to actually make the system work, a furnace 25%, 50% or twice as large as the btu's per hour, so its not struggling or running nonstop and never shuts off?

Last question for the morning, anyone want to venture a guess as the efficiency for the wood doctor owb I currently have now, seeing how I'm pretty sure its not 100% efficient and if it were 50% efficient or even less, I'd have to have that much larger of a boiler, correct?    Isn't the figure in btu's per hour, actual output needed after efficiency is factored into the equation.      

If the building would call for lets say for discussion sake, 100,000 btu's per hour and my furnace was 50% efficient, I'd actually need a boiler capable of putting out 200,000btu's per hour, not even considering the loss of efficiency in windows, insulation and etc.    Or am I wrong on this?


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## ditchdigger (Mar 16, 2014)

I used the math formula provided and will try to show some figures and you tell me where I went wrong.     

House number one, we took the figures of 7788 HDD days, and assuming it would have used far more than the average lp gas this year, we took 2000 gallons to use so 2000 gallons x's 91500 is 183,000,000 btu's of heat, then took 7788 x's 24 to get 186,912 and then 183,000,000 / 18,912 equals 979 btu's per hour, times temp differential of 120 [-40-80 for simple figures] equals 117,480 btu's per hour for the house alone.   If I did it wrong let me know where.  

Next is the shop and office, it got complicated due to some walls thicker than others, some odd shapes and given some estimates on sizes of shapes of the ceiling and walls. so bear with me.   

The office is 17 foot square x 8 feet tall and cement block and in floor heat, or 17x8x100 degree heat rise x's 4 cement block walls of virtually no insulation or 54400 btu's per hour.   The ceiling is 17x17 times 100 degree heat rise divided by R23 equals 1256 btu's and then the floor is heated and 17x17 x 60 degree's heat rise divided by 10 for the under floor insulation equals 1734 btu's of heat or a total of 57, 400 roughly for the office.  

Next is the shop, which is complex for the odd shaped walls and such but I'll attempt to narrow it down somewhat, two partial walls are only insulated block, total square footage is 376 square feet times 100 degree's, [-40- plus 60] and no insulation virtually or 37600 btu's per hour, the walls remaining are 3560 x's 100 and then have an R30 equals  11867 btu's per hour,

The ceiling is 23x80 feet long, x's 100 degree heat rise, divided by R38 equals 6737 btu's

The door is roughly 32x20 x's 100 degree's divided by R19 equals 3369 btu's per hour.   

The floor is 32x80x's 70 degree's heat rise divided by R10 for the foam board is 17920 btu's.    

The remaining end wall is going to be roughly 12 x 28 times 100 divided by R23 equals 1461 btu's

The windows should be roughly 2'x 3' times three of them x's 100 and virtually no insulation is 1800 btu's 

If I didn't forget something, did my math wrong, it should be about 80760 btu's for the shop alone, or the whole barn is 138160 btu's of heat per hour.     

Someone can tell me where I screwed up on my figures, but to me it doesn't come out right, we have the infloor heat going in the shop, and we added the knipco diesel heater when it was that cold out, and it was rated at 170,000 btu's and we never shut it off the whole time we were in the shop, plus the in floor heat, and in the office we had just a simple electric ceramic heater and was toasty warm in the office at all times,along with the infloor heat, that heater couldn't be much its rated at 1250 watt however that translates into for btu's.


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## NE WOOD BURNER (Mar 16, 2014)

http://sebels.wix.com/ebelsheatinginc#

This company has a wealth of knowledge! "Heaterman" is a regular here on the site.

he has been very helpful to me.


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