New House heating choices for unique situation

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Piston

Member
Dec 4, 2008
77
Upton, MA
My wife and I will be building a new home and we have been talking about what kind of heating system to use. It is still a ways away at this point as we are just closing on the property now, but I figured better to start planning earlier rather than later right?

The site is in Central NH and will be semi exposed to winds as it is on a hill side. We will have plenty of firewood on the site with roughly 30 acres of mixed hardwoods/softwoods. I've always enjoyed heating with wood as all of us do, and I would like to take advantage of the firewood on site to help heat the home. We have a Woodstock Fireview now that we both love, and heat our small 1400 sq ft home with in the winter time, the only problem is air circulation. The new house is going to be roughly 2,000 sq ft and have an open floor plan.

I know there are many options out there, but I've always been interested in wood furnaces. I've read a lot about OWB but not much about IWB. I am hoping you can help me by giving me some of the pros and cons for my specific situation.

Due to my career, I am often away for up to 3 weeks at a time, but then I may be home for a month or so, depending on my schedule. This matters in our choice because I know my wife won't be quite as willing as I am to go outside in the freezing cold and stoke the OWB! Ideally, I would love an OWB to heat with as my only fuel source, however I know that is not an option, since I will be away a good portion of the time.

I was thinking of a combination of either an OWB or IWB, and also an oil or propane furnace (I really hate the oil tank in my basement). However, is this combination practical? Am I better off just buying a standard furnace and putting in the basement, and heating with my woodstove as I am doing now?

I am just trying to find the most efficient way of heating our new home while taking advantage of free firewood (minus labor of course) but keeping in mind that my wife may not be willing to fill the OWB in a snow or rainstorm while I'm away. (I do think she would do it a good amount of the time, just not ALL the time. She routinely lights and tends the fire in the woodstove while I'm away, but mostly just uses the oil heat)

Oh, one more thing, we've pretty much decided on radiant floor heating, and absolutely ruled out forced hot air. Any advice for us?
 
Build an efficient home with energy conserving features, insulation, passive solar and heating it will not be a task! Should be some pros on this site that could show you the path to enlightenment! Ever see a masonry heater on YouTube?
 
If you ever plan to have a bank involved with the property or ever plan to sell it you need an accepted backup unattended heating system. Currently your choices are oil, propane or electric which includes straight resistance or geothermal. If you have decided to go radiant, I believe that that cuts out geothermal (but this is something to confirm). Wood pellet boilers are starting to be accepted as a primary heating method but this is still up for debate with some banks. Geothermal is very expensive up front so I wont spend a lot of time on it.

NH has an energy code that is the law but is rarely enforced in rural towns, if you build to that specification, your heating demand will be low. There are several builders in the state that specialize in very low energy usage houses which end up using far lower energy than the state minimum. If you plan to be in the house for awhile, spending money up front to cut your usage will pay back for the life of the house and cut down on the amount of time you are cutting wood. One of these pay me now of pay me later deals, pay more to build the house and then pay less over the long term to heat it. If you are on a windy hillside its real important to at a minimum do a flash and bat hybrid with a layer of sprayed foam on the inside of the exterior of the walls with fiberglass batts in the rest of the cavity or if you have money to spare have the walls completely foamed. I am an advocate of the putting 1/2" of Iso board foam on the inside of the studs to get rid of thermal bridges, but wall design is best left for another thread.

Since you want to burn wood as your primary heating source, you dont want to spend a lot of money on a backup system. This gets you down to off peak electric resistance heat or direct vent propane for backup. Having propane around is handy as then you can feed a generator if the power goes out (until the propane tank is empty).

When you build the house make sure you install storage. The more the better. There is a ultra low energy house for sale in Shelburne NH that was built 20 years ago that puts most modern low energy use houses to shame. It has 2500 gallons of storage with a Madawaska wood boiler (out of production very efficent gasifier) with a electric resistance coil in the storage for backup. The owner gets an off peak electric storage rate for his power and its about on par with buying wood. With a tight house, a large storage tank will take several days before the house is totally cold.

Of course being in Central NH, electric power is not neccessarilly a given so even though the bank and the insurance company is willing to let you use electric backup be aware that running a generator is not really an option with a 5 KW electric coil. If the house is vacant unless you have a automatic generator, the lack of electric power is going to keep any backup from running.

As for the boiler, you may want to take a visit to these folks in Lyme NH http://www.woodboilers.com/, they have been in business for 25 plus years and what they sell is going to last. If you think up front and cut your energy usage, you wont need a large unit.

With regards to OWB, dont. NH now requires a EPA phase 2 design which are expensive with more hassle than an IWB. OWB's make sense for a place with a large continuous heating load, if you build the right house, you should only need heat when its not sunny so an intermittent heating source with storage makes sense. If you are designing the house, make sure that you can easilly load wood into a wood bin in the basement which is close by the wood boiler to cut down on the dirt and dust which is inevitable with any wood fueled boiler.

Another thing to consider is Solar hot water heating. For six months per year up in Northern NH, I can shut down the entire heating system and just run off the sun. In the winter, if its sunny, the system provides a boost for my hot water. There are ways of generating DHW all year long but with a wood heating system I didnt want the extra added cost for evacuated tubes and their lower reliability (but some folks swear by them).

As for wood pellet boilers, as long as you are willing to cut your own wood, its hard to justify the initial cost of the pellet boiler and the ongoing premium for wood pellets versus free firewood in the backyard. One thing to think of is that proper firewood cutting is going to improve the quality of the woods around your house so you will get an added benefit. You also will not need to spend money for a health club as cutting wood will keep you active in the winter.

If you are anywhere near Plymouth NH you may want to check out this group http://www.plymouthenergy.org/, they are "Peak Oil end of the organized world" fanatics but as long as you ignore the hype, they are focused on a low energy lifestyle and are affiliated with a couple of firms and architects that do low energy houses.

Good luck, I know I covered a lot of things so PM if you need more info.
 
Piston said:
My wife and I will be building a new home and we have been talking about what kind of heating system to use. It is still a ways away at this point as we are just closing on the property now, but I figured better to start planning earlier rather than later right?

The site is in Central NH and will be semi exposed to winds as it is on a hill side. We will have plenty of firewood on the site with roughly 30 acres of mixed hardwoods/softwoods. I've always enjoyed heating with wood as all of us do, and I would like to take advantage of the firewood on site to help heat the home. We have a Woodstock Fireview now that we both love, and heat our small 1400 sq ft home with in the winter time, the only problem is air circulation. The new house is going to be roughly 2,000 sq ft and have an open floor plan.
I'd suggest starting by looking at how well you can insulate it before you work out how to heat it. Superinsulated houses (e.g. Passivhaus) have very, very low heating requirements - heating a house the size of the one you're planning on half a cord of wood a year is entirely plausible. Unless you're particularly interested in it there's no need to go all-out, but getting down to say a cord of wood for the entire year shouldn't be hard at all. The additional build cost for a highly insulated home isn't actually that much, it's mostly in getting the design and detailing right.

Piston said:
I was thinking of a combination of either an OWB or IWB, and also an oil or propane furnace (I really hate the oil tank in my basement). However, is this combination practical? Am I better off just buying a standard furnace and putting in the basement, and heating with my woodstove as I am doing now?
Do you even need a furnace? A cord of wood is ~6100kWh - or $760/year at 12.5 ¢/kWh. Assuming you do half your heating with a wood stove (because you like the ambience) and that's a $380/year bill for electric resistance heating. With oil currently at ~70% of the price of electricity, you're only going to save ~$120/year by putting in a furnace. That probably isn't a big enough cost difference to justify the amount you'd have to shell out for a furnace as opposed to electric baseboard heaters - which should also need less maintenance.

Piston said:
Oh, one more thing, we've pretty much decided on radiant floor heating, and absolutely ruled out forced hot air. Any advice for us?
Look closely at solar hot water systems. For a well insulated house, half your annual fuel bill may well be on hot water. If you oversize them, they should be able to provide all your heating and hot water from March - November quite happily.
If you're planning on radiant floor heating, and do end up going for very high insulation levels, it might be worth looking at stoves that put the majority of their heat out to water. They're much more common this side of the pond than in the US, but there are a couple of companies that do them (I think the rep for http://www.hydro-to-heat-convertor.com/ hangs out on these forums sometimes). If you do insulate well enough one of those should probably be enough for all your winter heating and hot water, and will be a great deal more pleasant for your wife to run than an OWB.
 
I would also think the wood stove and a small electric system to keep the bank happy with Soloar HW and possibly PV would the way to go.

A Wood Boiler of any type seems gross over kill.
 
Thank you for the replies so far. It seems as though everyone agrees that my first priority should be a well insulated home, and secondly I should decided on a heating system. I've been reading many other threads and I'm slowly learning that an OWB is probably not for me, however, I do really LOVE the idea of them.

I should have mentioned that we are planning on building a timber frame home, with SIPS as an enclosure system. Are SIPS considered 'super insulated' as you guys are describing?
Also, we do plan on living in this home for a very loooong time. We intend it to be our permanent home for as long as we live, and at age 30, hopefully that will be a long time.

Peakbagger,
Thank you for a lot of helpful information. I'm not at all opposed to geothermal, but I was always under the impression that it would cost me 40-50k for a installed system. Is it at all comparable to an OWB? If so that may be a very likely possibility, as long as I could still use it with radiant heat.
Heating with wood though is certainly a hobby for me. I do enjoy it and all the aspects that go along with it. I've been doing some more research on IWB and especially the dual fuel propane back up versions. I haven't learned a whole lot about them yet as I'm just starting to look into them.
I'm a little confused on the storage that goes along with the IWB? Is the storage tank separate from the IWB? How do they work in conjunction? Would I light a fire and keep it going until the storage tank is up to temp, and then let the fire go out for a while until the storage tank calls for more heat, then I have to relight the IWB each time?

Are IWB considerably cheaper than OWB? I came across the Tarm Excel and just curious of rough pricing for something like that? I do think my wife would be willing to fill an IWB as long as I made everything simple for her, like wood stacked in the same room as the boiler at a safe distance of course. I think she would be a lot more willing to fill one of those than an OWB.

If my house is very well insulated with SIPS, is even an IWB overkill?

PDF27,
I never even considered using electric heat. You make a good argument for it though if it takes that little to heat a well insulated home. I always thought that there was no place for electric heat in the north.
I should mention that regardless of the heating system we choose, we will have a central chimney with either our Woodstock Fireview we currently own, or the new Progress Hybrid if I decide to upgrade. We will also most likely have a woodstove in the basement (probably the current fireview if we upgrade)

I had no idea you could heat ANY home on a cord of wood per year. That is quite impressive.

I also didn't consider a solar hot water system either. Is that something I could run my radiant heat off of as well? I was initially planning on an on a tankless water heater, but if I can combine the water heater with something else, such as solor, or an IWB storage tank, then that is all that much better and more economical.

Please excuse my ignorance on some of these subjects. I know a lot about heating with wood with a woodstove, but little else. I've learned quite a bit about OWB but not IWB or geothermal. There is a lot of information to digest in these threads and I'm trying to as much as I can, but my brain can only handle so much information ina day :)
 
You can get to that standard of insulation with SIPs, but you need to be looking at something like 12" of external insulation on the outside of them. A lot of it is about detailing though - avoiding thermal bridges such as window frames or foundations where heat can go around the insulation. Unless you're very technical then you're going to need to get an architect/builder familiar with it to do the work for you. http://www.gologichomes.com/ in Maine have some fairly good videos which should give you an idea of what's involved - this sort of thing is routine in Germany and Austria, but hasn't really spread much outside yet.
Unless you're going super-insulated and getting some proper calculations done I'd be somewhat cautious going for pure electric heating - like I said, the devil is very much in the detail and if you miss the one small detail due to a mistake your electricity bills could be huge. Get it right though and they should be next to nothing. If you're planning to live there for the rest of your lives, then I'd strongly recommend getting an experienced architect or similar who does this sort of thing to look at it. They should at least be able to talk through the options with you and give you better ideas on price and the like.

If you're doing heating as well as hot water you will need a rather large solar panel (200 sq ft+) and have it close to vertical to optimise for the wintertime. For a superinsulated house, that size panel should do all your annual hot water plus shoulder season heating. Make the panel bigger and it'll do more, but if your heating requirements are already down to a single cord of wood you're cutting yourself there really isn't all that much economic sense to it. The NREL Red Book will give you data for flat plate collectors in your area (see http://rredc.nrel.gov/solar/pubs/redbook/PDFs/NH.PDF )
Not sure exactly how you guys do thermal stores in the US, but over here we have companies like Akvaterm who produce what by our standards are pretty large tanks (250 Gal+) which act as thermal batteries. Heat from various sources (solar, geothermal heat pump, wood boiler, electric immersion heater, etc.) goes in and then goes out again to various users like domestic hot water, radiant floors, etc.
 
Hi Piston,
Looks like you are located in Upton MA.
Next week there is the NESEA (New England Sustainable Energy Association) BuildingEnergy 2012 conference in Boston-MA http://www.nesea.org/be12/
All you need for your endeavor can be found there: passive haus desing, passive solar, SIPS, ICFs, solar hot water and even 5 or 6 wood/pellet boiler companies do have a booth.
Take a halve day off and visit this conference, it will proof worth the investment. ROI is at peak - sky is the limit.
This is a link to the professional directory of NESEA: http://www.nesea.org/greenpages/
You are on the right track: do it wright, design it once, and 30 years should be no problem.
Feel free to PM me, I'm in Burlington/Billerica MA and also at the Building Energy 2012 conference booth# 1064 - BTEC Biomass Thermal Energy Council.
 
Ditto Marcs response above. Excellent advice. Super insulate...passive solar..and you will get yourself into really small amounts of wood use. This is key. From there I see I see several options that work with your work situation:

if you centrally locate your woodstove near a two story atrium space ( a conservatively sized one) its possible for more parts of the house to utilize it. I have designed houses around a masonry heater also..an expensive option but will it will heat a house for many hours after the fire goes out.

option two: I have designed some houses with an an "intermediate" space for an enclosed Indoor wood boiler. This space is designed to allow for warm winter access but it "steers" the mess towards the outside. in other words you wont be schlepping wood to interior spaces. ( of course with a superinsulated space you wont be schlepping all that much) This hybrid mechanical room needs to be coordinated with the access to the woodlot..but it’s a great approach as it can be a workshop and even a "mans" mud room. Any outdoorsman's house needs a mans mud room where the wood shavings and heavy duty mud can be separated and filtered out. Substitue woman for my use of man as required. That’s the one thing missing from my house, we have a beautiful mud room for storage of food and all the clothing but it still has to be fairly clean. With me covered in wood chips for the month of February, thick clay mud during syrup season, ( I could go on) I could really use a mans mud room!

A lot depends on your lifestyle...how busy you are and all that jazz. Of course the best way to go is to would be nice to have both options wouldn’t it? A masonry heater or woodstove on the inside for third backup and the all so important aesthetic fire, but with a high efficiency gasification boiler as primary engine with a high efficiency gas hot water heater as another backup and summer domestic supply. Of course its easly to plug a solar hot water panel in also! Im big on redundancy as you can tell but having that woodstove or masonry heater sitting there nice and clean all week and then firing it up after a cold day in the woods is living the good life!

I will PM you.

Tim
 
I dont think you can justify geothermal and it not going to integrate well with radiant heat unless the technology has changed. Geothermal makes lots of warm water or air which is good for forced air heating. I expect someone sells a two stage system to further boost the heat up to the point where it would work well with radiant but the initial cost will be hard to justify.

If you have an IWB, the only way its going to run efficicently is with storage, otherwise, you will be spending far too much time lighting and relighting the unit. With a seperate storage tank, you run the boiler full bore until its hot, then the house runs off the hot water in the storage tank. Depending on the heat load you may not have to fire the boiler for days (spring and fall) or maybe once per day. If you do loose power, you dont need much for a generator as all you are running are some low wattage circulator pumps. The loss of power is a big issue in NH. Unless you are in town, the electric distribution grid can and does get knocked down a couple of times a year and every few years it can go down for days. Barring a major effort to rebuilt the distribution (highly unlikely as it would take a lot of character away from rural roads), you need a plan in place to heat your house without power.

The reason why I didnt recomend straight baseboard heat is your statement that you may be gone for couple of weeks at a time. It is real easy to just set the thermostat to 70 and forget to turn it down and I expect that your next electric bill after your trip will reflect that. Since you want radiant heat, adding electric baseboard is a lot of extra expense as compared to putting in one electric heater in a storage tank. Even if your spouse doesnt feed a stove, the cost for off peak electric storage heat is quite low in NH. Sure there is a option to install electric radiant with a woodstove for primary heat but you are back to buying power at normal rates.

In my opinion the disparity between off peak electric power and high demand period power is going to increase. That ultimately is the purpose that utilitities are in a rush to install smart meters, to shift the varying cost of power to the consumer and that means that you want the capability to buy power when no one else wants it at a discount and an electric coil in hot water storage tank does this.

I agree an IWB with storage is a bigger initial expense than a wood stove but unless you get creative, the wood stove is going to heat the space unevenly. I do have a friend with a woodstove with electric radiator backup and a hot water circulation system to even out the heat. It works for him but for most folks they just want to flip a switch.

By the way if you are looking at SIPS and what appears to be a high end build, do yourself a favor and hire an architect that specializes in energy efficient construction. Sure a builder can give you a good story but ultimately if they blow it on a design, good luck getting it remedied. An architect has a license and their reputation so they have an interest in getting it done right. Some folks complain about the extra cost up front but a good architect can save you money by getting the right folks to do the work and cutting back on rework. One last thing is if you do go with SIPs ask lots of questions about how carpenter ants will be kept from entering the walls and nesting. They do love to tunnel in foam and once they are in there you arent getting them out easily. They can be kept out but it require special detailing and some attention to the installation.
 
Marc,

Thanks for posting NEASA event schedule. seems we have much in common, Over the last 4 years i have initiated and been project architect for several pellet boiler installations. One is at the Wild Center in Tupper Lake NY...here is a video link. http://youtu.be/ycfYh5CbsNs another is at malone central school district where at the Board meeting last night they are reporting savings of over $1100.00 per day due to the two pellet boilers.

anyway, long story short, Im returning to residential design due to the downturn in K-12 work. I had a small practice from 1997-2008 and i was a member of NESEA then. Im rebooting my small firm-- Tim McCarthy Architect PC and If i can pull it off I my see you at the conference.

what ICF system did you use in your house?

tim
 
peakbagger said:
I dont think you can justify geothermal and it not going to integrate well with radiant heat unless the technology has changed. Geothermal makes lots of warm water or air which is good for forced air heating. I expect someone sells a two stage system to further boost the heat up to the point where it would work well with radiant but the initial cost will be hard to justify.
Radiant Floor heating (as Piston was talking about) uses very cool water for heating - much cooler than you can make use of with forced air heating. It's other forms of heat (e.g. radiators) where you need higher temperatures and heat pumps fall down, but for radiant floors geothermal heat pumps are pretty good. Whether you can justify the capital cost is another matter.

peakbagger said:
The reason why I didnt recomend straight baseboard heat is your statement that you may be gone for couple of weeks at a time. It is real easy to just set the thermostat to 70 and forget to turn it down and I expect that your next electric bill after your trip will reflect that. Since you want radiant heat, adding electric baseboard is a lot of extra expense as compared to putting in one electric heater in a storage tank. Even if your spouse doesnt feed a stove, the cost for off peak electric storage heat is quite low in NH. Sure there is a option to install electric radiant with a woodstove for primary heat but you are back to buying power at normal rates.
Depends how much heat you're using, and how committed to radiant floors you are. If you definitely want them, then I agree an electric heater on the storage tank is a no-brainer (particularly if you want to use solar hot water as well). If you're less bothered then you stand to save a lot of money on not needing to install the radiant flooring, and for low electricity consumption even the 50% lower cost of off-peak electricity saves maybe $150/year. If you've saved thousands on the floor, that may not be such a bad deal.
Personally in that situation a radiant floor running off a big thermal store is what I'd go for, but other people will have different priorities.

Oh, one thing I don't think anybody has mentioned yet - what direction does the site face in? You've mentioned it's on a hillside, so presumably you'll want the house to face downhill for the best views. Orientation makes a big difference for passive solar heating in winter - it won't heat the house for you, but will make a big dent in heating bills. If the house is going to be facing North, unless you have a particular desire to live in a windowless cave and don't want to go for massive insulation you're unavoidably going to end up needing more heating and should be thinking about the larger, more complex heating systems. If it's south facing and you're willing to go all out on insulation/windows then you can look at smaller, simpler/cheaper heating systems since you just won't need as much from them.
 
A radiant floor may be over kill for a super insulated house.
 
Oh, one thing I don’t think anybody has mentioned yet - what direction does the site face in? You’ve mentioned it’s on a hillside, so presumably you’ll want the house to face downhill for the best views. Orientation makes a big difference for passive solar heating in winter - it won’t heat the house for you, but will make a big dent in heating bills. If the house is going to be facing North, unless you have a particular desire to live in a windowless cave and don’t want to go for massive insulation you’re unavoidably going to end up needing more heating and should be thinking about the larger, more complex heating systems. If it’s south facing and you’re willing to go all out on insulation/windows then you can look at smaller, simpler/cheaper heating systems since you just won’t need as much from them.
Pdf,
Unfortunately you are correct, the house will be on the North side of the hill, with views to the East, North, and West. The only one I'm missing, south, is the one I wish I had. I will inevitably have a decent amount of windows on the North wall. I'd like to try and incorporate a solarium on the south wall if possible, it would be a good spot for some solar gain and for 'seed starting' in the beginning of spring.

I didn't realize a 'super insulated' house had somewhere around an additional 12" of insulation on the outside of the SIPS! For now, I'm not planning on a 'super insulated' house as you guys are describing, rather a well insulated house that surpasses the minimum for code. I don't think I'll be heating my home on one cord of wood per winter.

So I guess for planning purposes, I should state that we intend to insulate our home using good quality windows and SIP enclosure, but probably only SIP's, not additional insulation on the outside.

I do think I can rule out an OWB at this point. It sounds like my main options with what I want, radiant heat, would be either a dual fuel IWB with woodstove as a backup in case power goes out and I don't want to listen to my generator run......OR....a traditional style gas or oil furnace with woodstove as my supplemental heat.

I'm leaning towards the first option, the dual fuel IWB, but still have many questions about them.

How does the IWB heat up the storage tank? How does the system in general work? I understand this has probably been covered a number of times but if you could post any 'especially good descriptions' on the topic that would lead me in the right direction it would be appreciated.

Also, in a well insulated home as I've described, would I expect to light the IWB to heat up the storage tank, then let it go out for a number of hours, or possibly day or so, then RELIGHT every day or every other day? I don't like the idea of relighting all the time, but rather just adding wood every 8 hours or so.

If I had an IWB with storage, would I be able to run all my radiant heat and my hot water off that one tank? Or would I need a separate hot water heater?

Could I tie in an additional heating zone down the road if I were to put an addition on the house, such as a first floor master bedroom?
 
PassionForFire&Water; said:
Hi Piston,
Looks like you are located in Upton MA.
Next week there is the NESEA (New England Sustainable Energy Association) BuildingEnergy 2012 conference in Boston-MA http://www.nesea.org/be12/
All you need for your endeavor can be found there: passive haus desing, passive solar, SIPS, ICFs, solar hot water and even 5 or 6 wood/pellet boiler companies do have a booth.
Take a halve day off and visit this conference, it will proof worth the investment. ROI is at peak - sky is the limit.
This is a link to the professional directory of NESEA: http://www.nesea.org/greenpages/
You are on the right track: do it wright, design it once, and 30 years should be no problem.
Feel free to PM me, I'm in Burlington/Billerica MA and also at the Building Energy 2012 conference booth# 1064 - BTEC Biomass Thermal Energy Council.

Marc,
Unfortunately I won't be able to attend. I'd really love to but can't get away from work, it sounds like it would answer a lot of my questions though. Regardless, thank you for posting.
 
The thickness of the insulation needed has been overstated but not the need for all the component parts to work in common.

The biggest issue you seem to have is aspect. Not much you can do about that.
 
If I had an IWB with storage, would I be able to run all my radiant heat and my hot water off that one tank? Or would I need a separate hot water heater?

Your storage tank just holds on to the heat from your boiler for you. Then lets you draw it out when you have the demand for the heat. A well insulated tank(s) can give you many hours. Or a day or two of heat. It all depends on how much storage you have and the heat demand you ask from it, and how well you insulate it.

There are lots of ways to design a system. If you go with a pressurized system, like I would recommend, one way to do it is with a seperate hot water heater, called an indirect water heater, that your wood boiler/storage tank water will heat. Mine is a Triangle Tube Smart Series indirect hot water tank. Here is a link for you. http://www.triangletube.com/TriangleTubeProduct.aspx?CatID=6&PID=2 They are excellent. A tank inside of a tank. Your water from your boiler/storage tank system never mixes with your Domestic Hot Water(DHW). That would not be good. Keep asking questions. Lots of good people in the boiler room.
 
Piston, for what it's worth, here is a picture of my non-pressurized 850 gallon heat storage tank, taken when I had the top off after adding one more heat exchange coil (the one with the new-copper shine) to replace the radiator on my Kubota generator--as per the second picture. (We live off-grid, with solar, wind and, when unavoidable, diesel to keep the batteries charged.)

The water in the tank is nothing more than mass to hold heat. It could have been sand, in theory at least. The water in the picture was the very same as had been initially been put in the tank some 4-5 years previous.

I have two boilers--one oil and one a wood gasification boiler. They provide heat to the heat storage tank via heat exchange coils as seen in the picture. When the house requires heat for the in-floor radiant system, the heat is drawn from the heat storage unit. Same goes with DHW. When we turn on a hot water tap, the hot water comes via the DHW exchange coil in the heat storage tank.

When the boilers are running (whether wood or oil), they are adding heat to the heat storage tank. This is critical for the wood boiler, as it allows me to burn the boiler 'full-out' for the most efficient burn possible, in effect simply transferring the BTU's in the firewood to the heat storage tank.

I also have a solar thermal array which helps heat the storage tank in the summer, when the only heat demand is DHW. I don't like burning wood (or oil, for that matter) in the summer.

For what it's worth, my wife and I LOVE our radiant heat. We also plumbed in heated towel racks in the bathrooms. We do have wood stoves (three of them in various rooms) for backup and for the aesthetic pleasure they provide.

Also cannot resist commenting on the noisy generator comment. I built a well-insulated gen shed with a hospital quality muffler. Unless you are standing next to the gen shed, it is impossible to hear it running.

Finally, it is well worth your while if you can find a good and knowledgeable architect. I would humbly suggest two criteria: First is that he/she is familiar with the kind of building you are hoping to build. For us it meant someone who understood the challenges and the options for living off-grid in the North, fully familiar with alternative energy and efficiencies. Secondly, make sure it is an architect whose passion comes from making your dreams and hopes a reality as opposed to making his/her dreams and hopes a reality (using your $$). In my experience architects fall into one or the other category and I have gone so far as to ask which they are before going any further.

Wish you every success! Sounds like a fun project, bringing back lots of memories!

Barrett
 

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Gasifier,
Thanks for the explanation and link to the "tank in tank" water heater. I've never seen one of those before.


Barrett,
Thanks for the pics, it's neat to see what the inside of a storage tank can look like. I think that is an incredibly good idea to use the heat sink as a radiator for your generator! Great use of otherwise wasted heat.

I understand the theory of the storage tank pretty well now. It's all starting to come together finally! :)

How well insulated is your home?

Your situation sounds very....very cool!
 
Piston said:
How well insulated is your home?

We have R32 in the walls and R60 in the ceiling. The exterior walls are double-walled, with 2x6 (with R20) studs on the outside and off-set 2x4 (with R12) on the inside. Makes for lovely deep-set windows with ledges. The ceiling is blown-in cellulose insulation for the most part (vaulted ceiling has mix of fibreglass bats and high density foam boards).

Windows are only double glazed, but we wanted the aesthetics of wood-frame, double-hung windows and were willing to sacrifice some efficiency. (Folks up here are now often going for triple and even quadruple paned windows.)

There are always trade-offs. No windows at all would be most efficient. But I don't mind burning the extra wood to have a home that I really love. :)

Barrett

P.S. Aerial view of the property is attached--water is the Yukon River.
 

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Wow, im amazed at the quality of knowledge here. Great comments on architects Onfoot, and i like the open atmosphere storage storage and muffler. thanks for posting...
 
Just a note: I've been reading up on ICF this morning and was wrong to think you wouldn't be able to reach Passivhaus standards with just ICF. At least one of the systems out there goes up to R-84, which is more than enough to reach the insulation requirements.
 
My first post to hearth, so don't beat me up to bad. I have been a long time lurker.

I agree with the others about building a house that goes above and beyond what building codes call for. I put a addition on my house last year and kick myself to this day for not doing ICFs. My contractor did not have much experience with them so I went with a block basement that is insulated with closed cell insulation below ground.

As part of the addition, we installed a forced air GSHP by Waterfurnace. Waterfurnace does make a GSHP that you can tie into your radiant floor heating. I have the Envision two stage air - air GSHP. When the HVAC company came out and did their final methanol filling and pressurization of the system, the air temperature coming out of the plenum was 110F. The loop temperature at that time was around 60F. I would think that 110F water would be warm enough for a radiant floor system. You also should get a couple more price quotes. My system, after the government rebate came in a little above 10K, it also cools and makes hot water.

The GSHP has added approximately 50 - 60$ a month onto our "normal" electric bill. I cannot complain since we were spending that much in propane to heat a fairly well insulated 1400sq ft ranch during the shoulder seasons when we were not burning wood. We are heating / cooling approximately 2200sq ft now. I also have a PSG Caddy furnace that I burn when temps are in the 30s or below. This also helps keep our electric bill down and GSHP loop temperatures up.

Any questions about the GSHP let me know.

Thanks,

Scott
 
Onfoot said:
Piston said:
How well insulated is your home?

. The exterior walls are double-walled, with 2x6 (with R20) studs on the outside and off-set 2x4 (with R12) on the inside.


I think that method is also a very good sound proofing system
 
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