Im trying to figure out what would be the best system for me with money no issue. I am building a rancher approx. 1800 sq ft . on a slab with no basement. My walls will be 2x6 with r20 plus 2 inch Styrofoam on outside of walls for approx. r35 walls. I will have infloor pex for hot water in floor heating. My system would be outdoors approx. 75 feet from my home or 100 feet. Any suggestions is greatly appreciated whether I should buy OWB or gasifier unit,,most of my wood would be birch....I can build a small building say 10 x 10 for a indoor unit if that would be better...thanks for any info.
Whats best for 1800 sq foot home?
- Thread starter andrew goodwin
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Based on the description if the slab is also well insulated, you won't need much supplemental heat for the house at all. Will there be other buildings heated by the boiler? If not, I would be very careful with overkill on the heating side. Your lights, refrigerator, bodies, etc. will contribute to heating a very tight house. Get a heating load analysis done. Then look at the design btus and decide. A small efficient woodstove could even be overkill, but at least you can open a window or two if it is.
My indoor gasser is about 100ft away in another building. I like it that way. Also i am spoiled in the fact that i stack all my wood on pallets and move them with a tractor. minimal handling of wood.
A gasser will burn a lot less wood than an OWb, and no smoke issues. 99% of time gasser's don't smoke, just a little on start up.
curious, what state are you located?
Also, smartr move on the R factors. Should heat with a candle
A gasser will burn a lot less wood than an OWb, and no smoke issues. 99% of time gasser's don't smoke, just a little on start up.
curious, what state are you located?
Also, smartr move on the R factors. Should heat with a candle
I live in Prince Edward Island Canada,,east coast,,so we have some nasty winters at times.. It would be just my home ,,im putting two layers of 2 inch Styrofoam under the slab....I really didn't want a wood stove due to worrying about house fires all the time..
I was trying to stay away from the wood stoves due to the potential of house fires..
I'm just south of houlton by 40 miles. Whenever we get nor' easters glancing off us and going out to sea, you and Nova Scotia get slammed.
I would not chose an OWB over an indoor gassifier - don't think I'd ever chose an OWB over anything actually.
If you're set on not having it in the house, I would seriously consider a Garn Jr. in an insulated outside shed. Make the shed nice & big, big enough for your winters wood and extra room for workshop space. Not sure what the ins & outs of getting a Garn in this neck of the woods are though.
If you're set on not having it in the house, I would seriously consider a Garn Jr. in an insulated outside shed. Make the shed nice & big, big enough for your winters wood and extra room for workshop space. Not sure what the ins & outs of getting a Garn in this neck of the woods are though.
The garn jr looks to be a large beast..wouldn't this be way overkill for a 1800 sq foot home....
I was thinking of a woodstove but how do I get the heat from section of the home to another,,it would basically only heat the one room
Heat distribution would depend on the floor plan. If it is like a typical rambler with living room, kitchen and dining area on one end and bedrooms connected off a hallway on the other end the solution is simple, blow air from the cooler area toward the stove. For more even heat in the house put a table or box fan at the far end of the hallway, placed on the floor, pointing toward the woodstove. Run it on low speed. It will blow the cooler air down low, toward the woodstove. The denser cool air will be replaced with lighter warm air from the stove room. Running this way you should notice at least a 5F increase in the hallway temp after about 30 minutes running. Or in your case you could build in an insulated duct with an intatke grille at the far end of the hallway and it's outlet in the stove room area near the stove. A small inline fan of 150cfm would be sufficient to balance the heat.
It sounds like the house is going to need very little supplemental heat. Are there frequent power outages in this area? If so how long do they last? What is the worst case scenario?
It sounds like the house is going to need very little supplemental heat. Are there frequent power outages in this area? If so how long do they last? What is the worst case scenario?
Maple1 might be able to help you with that, he's next door in Nova Scotia. Not sure whats available on that side of the lines. My gasser is an indoor unit inside a insulated building. Works well. Choosing a gasser is knida like choosing a car. it's what you like and can get.
Also, do you know about thermal storage? I have 820 gals of storage, uaully do 1 fire every 4 or 5 days for DHW in summer. One fire a day for middle of winter will heat what i need. It works very well with radiant heat. A nice convenience factor for firings
Also, you need wood cut/split/stacked for close to a year(actually longer the better), for a gasser to burn properly. preferably 18 months to 2 yrs really makes a difference in performance.
Get a heatloss calc. done and then decide what size boiler you need. Go with a gasser in my opinion
No. What it doesn't need at the time it stores in its built in storage - and the more storage the better. You might be able to go a couple of days between fires with enough storage.The Garn would be no more overkill than any other boiler - so maybe you don't need a boiler? But you're going with in-floor heat so a boiler of some kind is pretty well a necessity. After living with it for a year, I would also suggest storage is a necessity for anyone with a wood burning boiler.
Willyswagon on here is also in PEI, he has an Empyre Elite. I think he is happy with it, but also think I did read on here him saying that he might have done the Garn Jr. if it had been out then. There are also some very nice looking boilers on the market now.
Hey Andrew, what part of the Island are you in?
I agree with heat loss calculations first, then design from there.
If I was starting with a fresh build, with $$ no issue as you mentioned above, there would be no need for wood heat.
I'd build a super tight, air controlled home and go with a heat pump(air to air).Solar DHW with electric back up.
I am very happy with my present set up, but if I was to do it again in this old house I would have loved to and may still get a Garn Jr.
If you want to have a look at my set up just let me know. If for some reason you are stuck on the idea of a boiler, get an indoor unit!
Going out in the winter sucks, unless your going snowshoeing, skiing, or plowing snow in this!
![[Hearth.com] Whats best for 1800 sq foot home?](/talk/proxy.php?image=http%3A%2F%2Fi242.photobucket.com%2Falbums%2Fff113%2Fwillyswagon-2007%2Fgreenfleet052_zps49fec0ae.jpg&hash=c88402e03ffa68e21d2c68c2a2546143 "[Hearth.com] Whats best for 1800 sq foot home?")
I agree with heat loss calculations first, then design from there.
If I was starting with a fresh build, with $$ no issue as you mentioned above, there would be no need for wood heat.
I'd build a super tight, air controlled home and go with a heat pump(air to air).Solar DHW with electric back up.
I am very happy with my present set up, but if I was to do it again in this old house I would have loved to and may still get a Garn Jr.
If you want to have a look at my set up just let me know. If for some reason you are stuck on the idea of a boiler, get an indoor unit!
Going out in the winter sucks, unless your going snowshoeing, skiing, or plowing snow in this!
![[Hearth.com] Whats best for 1800 sq foot home?](http://s242.photobucket.com/user/willyswagon-2007/media/greenfleet052_zps49fec0ae.jpg.html "[Hearth.com] Whats best for 1800 sq foot home?")
The problem with just about any wood boiler that you encounter when heating a home like yours with a small heat load is the "IDLE Time". These are long periods when there is no demand for heat so the fire just smolders, making the boiler very inefficient plus it generates large amounts of creosote.
Storage gives the boiler a reason to burn flat out until storage is up to temperature. (this is called batch burning) This method of batch burning with gasification boiler makes for a clean and efficient burn.
Put a Garn Junior in an out building and you would never look back. The unit is simple in design and operation and the company has a good track record, I believe going back to 1983, with parts still available for some of its earliest units.
This is a bigger unit but same principal of operation.
Good Luck!
I'd ditch the radiant slab heating, build a super-tight home with a heat pump w/hvac and central wood stove for a back up.
I've talked to a number of folks that have done radiant slab heating and they discouraged me. Major problem is having to keep a constant temp, so no setback thermostats.
I've talked to a number of folks that have done radiant slab heating and they discouraged me. Major problem is having to keep a constant temp, so no setback thermostats.
Hi Andrew,
If money is not an issue...hire a Passivhaus consultant. If you achieve passivhaus standard(4.75K btu/sq.ft/year) an 1800 sq ft house would have an annual heat load of 8.5MM btus.That is the equivalent of less than half a cord of wood-for the YEAR!
If a high degree of long term affordable comfort is your goal than your building enclosure comes waaaay before a $20k+ heating system that will require a lot of time/effort on your part.
My minimum for new construction in your climate would be:
R5 windows-triple pane, high solar heat gain coefficient(SHGC) on the south facing glass (with proper summer shading)
R20 under slab-sounds like you've got this covered but pay close attention to your slab edge detail.
R40 walls. This is whole wall performance R value and would take a bit more exterior foam to achieve this than you are planning on(your wall design has a whole wall R value in the mid to upper R20's depending on the type of foam you go with-EPS, XPS, Poly ISO.
R60 attic. If you go with trusses get energy heel trusses. This allows for ventilation and plenty of insulation above your exterior walls. Then lay on the cellulose nice and heavy.
<1 ACH/50pa. This is your air tightness measured by a blower door test and install and HRV system to keep everyone healthy and happy.
And a simple heating system to top it off. My choice would be a mini split heat pump and a wood stove for when it is really cold and for backup assuming an open floor plan.
I recommend http://www.greenbuildingadvisor.com/ and http://www.buildingscience.com/ for lots of good reading.
Good luck,
Noah
If money is not an issue...hire a Passivhaus consultant. If you achieve passivhaus standard(4.75K btu/sq.ft/year) an 1800 sq ft house would have an annual heat load of 8.5MM btus.That is the equivalent of less than half a cord of wood-for the YEAR!
If a high degree of long term affordable comfort is your goal than your building enclosure comes waaaay before a $20k+ heating system that will require a lot of time/effort on your part.
My minimum for new construction in your climate would be:
R5 windows-triple pane, high solar heat gain coefficient(SHGC) on the south facing glass (with proper summer shading)
R20 under slab-sounds like you've got this covered but pay close attention to your slab edge detail.
R40 walls. This is whole wall performance R value and would take a bit more exterior foam to achieve this than you are planning on(your wall design has a whole wall R value in the mid to upper R20's depending on the type of foam you go with-EPS, XPS, Poly ISO.
R60 attic. If you go with trusses get energy heel trusses. This allows for ventilation and plenty of insulation above your exterior walls. Then lay on the cellulose nice and heavy.
<1 ACH/50pa. This is your air tightness measured by a blower door test and install and HRV system to keep everyone healthy and happy.
And a simple heating system to top it off. My choice would be a mini split heat pump and a wood stove for when it is really cold and for backup assuming an open floor plan.
I recommend http://www.greenbuildingadvisor.com/ and http://www.buildingscience.com/ for lots of good reading.
Good luck,
Noah
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When you get a structure down below 10BTU/sq ft, investing thousands of $$ in a wood heat system really gets questionable. Given how much I like to promote heating with wood, I still feel obligated to say that.
If you have no reservations about using electricity for heating, I would really consider a Mitsubishi heat pump system that uses inverter technology to provide heating and cooling if/when you ever need it. Then supplement it with a small wood stove in the house. Note the word small. Chimney fires happen for two main reasons. Poor wood quality (not seasoned properly) and long periods of idling that allow creosote to build up. Sizing the wood stove correctly will eliminate the idling part of the equation and seasoning the wood is up to you.
Going with what you described for insulation I would bet that your house will not need much over 20,000 -25,000 btu at peak load. For 90% of the winter it will be well below that. Recovering the cost of a gasifier + storage or a Garn Jr with integral storage would take a very, very long time.
I will reiterate what others have said regarding storage, maybe even a little more forcefully...... With a heating load that low, storage is going to be absolutely mandatory for your application. Even a small wood gasser in the 25KW range will be substantially oversized and would deliver pretty marginal performance for you. If you install a wood burning boiler it should definitely be set up to batch burn rather than cycle the fire up and down or you will be buying yourself some misery.
It's interesting to note that in Europe I saw pellet boilers that had maximum outputs in the 20,000 btu range (7-9KW) for homes just like you are describing. Much of the new construction over there is designed to be near zero heat load. The Windhager BioWin100 pellet boiler available here fires from about 33,000 but all the way down to the 10-11,000 range. That would be the size range you would be looking at for a ow energy house.
If you have no reservations about using electricity for heating, I would really consider a Mitsubishi heat pump system that uses inverter technology to provide heating and cooling if/when you ever need it. Then supplement it with a small wood stove in the house. Note the word small. Chimney fires happen for two main reasons. Poor wood quality (not seasoned properly) and long periods of idling that allow creosote to build up. Sizing the wood stove correctly will eliminate the idling part of the equation and seasoning the wood is up to you.
Going with what you described for insulation I would bet that your house will not need much over 20,000 -25,000 btu at peak load. For 90% of the winter it will be well below that. Recovering the cost of a gasifier + storage or a Garn Jr with integral storage would take a very, very long time.
I will reiterate what others have said regarding storage, maybe even a little more forcefully...... With a heating load that low, storage is going to be absolutely mandatory for your application. Even a small wood gasser in the 25KW range will be substantially oversized and would deliver pretty marginal performance for you. If you install a wood burning boiler it should definitely be set up to batch burn rather than cycle the fire up and down or you will be buying yourself some misery.
It's interesting to note that in Europe I saw pellet boilers that had maximum outputs in the 20,000 btu range (7-9KW) for homes just like you are describing. Much of the new construction over there is designed to be near zero heat load. The Windhager BioWin100 pellet boiler available here fires from about 33,000 but all the way down to the 10-11,000 range. That would be the size range you would be looking at for a ow energy house.
Well said heaterman. That's good, helpful info. The Mitsubishi HyperHeat heatpumps seem to be a good match for what I suspect will be the average heating load on this house. Having a small catalytic wood stove (with dry wood) would be a good backup for extreme cold events and power outages. As a backup alternative go with a quality vented propane or nat gas fireplace like a Valor unit.
Any housefires involving wood stoves usually are not the fault of the stoves, rather of faulty installation or carelessness. I have 4 wood stoves(in different properties) and i never worry about house fires.
Have to agree with Heatermans comments. When we are doing net zero housing here it's very common to get below 10 btu/sq ft. Actually that's one of the goals. We were finding that most heating systems were way too large. Thanks to modulating/condensing tech that is solved.
If you are doing the wood as a choice i.e.: you just like it.....then like HM said storage for you is a must. Keep the radiant slabs if you want them....your heating load/cost will be a fraction of what others think/experience. Do give some thought to zoning the slab so you can have different rooms at different temps if you wish. Do insulate the perimeter of the slab to stop/reduce conduction of heat to the cold exterior.
If you want the cordwood boiler but don't want the mess in the house put it in an exterior building/garage/shop & pipe the hot water into the home; note reading the stickies that apply to your situation at the top of the boiler room page is a very good thing. You will find that the majority here favour an indoor gasification cordwood boiler over any OWB with good reason.
You have started from a good place (asking questions) before you build.
If you are doing the wood as a choice i.e.: you just like it.....then like HM said storage for you is a must. Keep the radiant slabs if you want them....your heating load/cost will be a fraction of what others think/experience. Do give some thought to zoning the slab so you can have different rooms at different temps if you wish. Do insulate the perimeter of the slab to stop/reduce conduction of heat to the cold exterior.
If you want the cordwood boiler but don't want the mess in the house put it in an exterior building/garage/shop & pipe the hot water into the home; note reading the stickies that apply to your situation at the top of the boiler room page is a very good thing. You will find that the majority here favour an indoor gasification cordwood boiler over any OWB with good reason.
You have started from a good place (asking questions) before you build.
One other thought. If cost is not the object, would a good ground source heat pump work here? I'm thinking a Bosch unit.
As I've noted in other threads, Ive got a 18000 btu and a 12,000btu Mitsu air source heat pump. Hyper models. Impressive. The model 18 uses 1270 watts when cooling and 1540 watts when heating(outside air temp47f) and when it gets down to 17f it's using 2620 watts for heating. It's nice to be able to use an air sourced heat pump for both cooling and heating. Years ago the units weren't worth the coin, due to the ineffective/expensive heat mode.
I'm with the others, if i was to rebuild I would do R40 wall and R60 ceilings and heat pump with a wood stove or probably a pellet stove.
I'm with the others, if i was to rebuild I would do R40 wall and R60 ceilings and heat pump with a wood stove or probably a pellet stove.
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