Trying to be realistic - about the prices of masonry heaters, etc.

[Burn-1]

I am considering getting into the business of actually manufacturing soapstone heaters, since the cost today seems way out of whack in relation to the material costs. They are also fitted together with splines and pins as opposed to mortared joints, so assembly is not quite the same kind of work as a conventional masonry heater. Once one adds services like custom 3D carving into the picture, one is entering a market where there are very few players and hardly any locals.

Yes the Tulikivis are mostly built with splines and other hardware as in the Tulikivi in this video. But some others such as this system from Tigchel Heater based in the Netherlands, (don't know about US availability), are stackable systems made from pre-cast refractory materials. It appears to use gaskets and interlocking pieces not unlike the Topolino stove I had previously mentioned.

According to that website the Tigchel heater is good for about 100 square meters or ~1,100 SF. Given that European homes are generally much smaller than ours that's probably a great investment but 1,100 SF is like the output of a Hearthstone Craftsbury or VC Intrepid for a little perspective.

 

[KeithO]

On the material side: Soapstone has a density of approximately 2800kg/m3. Thus, assuming the 60mm thick slabs that are readily available, 30 slabs will have a weight of ~2300lb. Thus more than enough to qualify as a masonry heater. These slabs will have a material cost of less than $2000. The big benefit to soapstone is that it endures the high temperatures in the heater core better than regular firebrick. One is thus able to manufacture most of the parts for the heater out of the same basic material.

Soapstone can be machined with regular carbide cutters. In fact the edges can be routed with a regular router with carbide tipped bits. It will of course produce a lot of dust, so this is a factor that needs to be planned for. The kind of machining done to the soapstone slabs is neither complicated nor terribly time intensive. Slots for splines, holes for dowels and bolts, edge treatment to make the outside surfaces look nice. Perhaps all of the edges are given a "lick" to ensure than all pieces are identical in size and edges parallel and square. The edges as supplied are more than likely sawn, thus would need some improvement.

I think that the best thing about soapstone is that in the development phase, one can assemble and disassemble the heater many times to replace pieces in the core without requiring demolition of the unit. The MHA fols appear to use a clay mortar for their experimental units so that they too can be disassembled and "recycled" but that is far more tedious.

The only downside to the whole enterprise is that soapstone s not found everywhere, so freight of the raw material is a factor after which the instalation is the next issue (and an additional cost besides the heater itself). I do think that we can do a lot better than $20k/heater though. At those prices one could live quite well doing 1 heater per month. In the case of Tulikivi and others, the primary cost of material and labor is incurred in Finland and one has to add shipping across the atlantic + road transport to the distributor / reseller, stocking fees, salesmans commission, delivery and instalation.

 

[Martin Strand III]

The big benefit to soapstone is that it endures the high temperatures in the heater core better than regular firebrick. One is thus able to manufacture most of the parts for the heater out of the same basic material.

Keith:

I'll venture that both soapstone and brick can equally endure constant high temperatures - it's the brutal heating/cooling cycling (thermal cycling) where soapstone may win out.

But, yes, soapstone is nice. Nice and old; formed under intense heat and pressure millions of years ago. Nice to work with; cut and shape. Nice and heavy; good for thermal mass. Nice and stable under high firebox heat followed by a cool phase; potentially fewer cracks and thermal cycling damage. Nice to feel; almost sensuous. Nice to look at; for a heater, eye candy. Nice and expensive to buy; could be tough on a budget...

Those nice cudos given, soapstone is not quite as nice for thermal mass heating as other natural substances in one very important aspect: because of it's 'high thermal conductivity'. I've said this before - this property makes soapstone more like metal than other natural masonry (see below thermal conductivity values). The real world meaning, comparing it to other natural masonry, is that soapstone heats up fast (good) but also cools down fast (not so good for a heater). In other words, once it's hot, it cools faster than other masonry making it less desirable for a masonry heater. None the less, it's much better than a metal stove.

MATERIAL                               THERMAL CONDUCTIVITY W/mK   (Btu-in/hr-ft-F)
 

Cast Iron                                                75 (520)
Soapstone                                              6 - 7 (42 - 48)
Granite                                                   about 3 (20.8)
Face brick                                               1.29 (9)
Firebrick, Clay (ASTMC62)                     0.95 (6.6)

So, soapstone is over 5X more thermally conductive than other masonry but about 10X less conductive than metal (iron).

Maybe it's splitting hairs. For me, I liked pocketting the difference in cost in not having soapstone and knowing brick and tile (my facade over a refractory core) is as good or better in this one important feature.

Aye,
Marty

Grandma used to say, "To each his own."

 

[KeithO]

Marty, what I'm saying on the cost side is that I think the cost actually favors soapstone. The Albiecore heater kit runs close to $4k and that is without facing. The core itself, which is pimarily castable refractory is $1600 alone. This link http://www.greenmountainsoapstone.com/masonry_heaters.html takes you to the place where one can purchase the soapstone slabs. The prices are not available online, one has to call and I confirmed that cost of $63 for the 700x300x60 slabs.

Greenmountain is a lot more reasonable in price than most other places. Generally, I have the impression that soapstone is hugely marked up by all the middlemen. If you like granite, how about this http://www.use-enco.com/CGI/INSRIT?PMAKA=640-0120&PMPXNO=949402&PARTPG=INLMK3 Precision ground and lapped granite surface plates 12x18" x3" thick for $24 ? Just remember that any decorative touches (bevels, rounded corners, slots, holes etc) are not going to be cheap. One could build a nice heater with it, but it would suit a "modern" home better because it would be kind of monolithic.

It just gives you an idea of to what extent we are ripped off for granite countertops and the like. The smaller 9x12x2" plate is just a little more expensive than what one pays for 1/4" granite tile by the sq ft. Imagine using 2" thick "tiles" for your flooring. That would add a bit of thermal mass and last forever too. One could regrind the surface every 100 years to take out the few 10ths of wear that one would have by then... I can imagine the face of the enco salesman when he gets the call: Hello ? Yes, I would like 1600sq ft of the 2" surface plate please. But sir, what are you going to do with so many surface plates ? Uhhh, tile the floor with them ?....

http://www.use-enco.com/CGI/INSRIT?PMAKA=640-0140&PMPXNO=951363&PARTPG=INLMK3 The 18x24x3" plate works out to $15/sqft. It would of course be a good 2 man job laying those suckers (180lb each), but one wouldn't need too many to get the job done.

 

[Martin Strand III]

Keith:

I don't think we're on the same page.

I'm done here.

Aye,
Marty

Grandma used to say, "Some can't see the forest from the trees.''

 

[Todd]

Well for an out of the box solution, practically a masonry heater on its own you could also grab a Hearthstone Equinox (Big hat tip to Tom for featuring it on his very informative site when Hearthstone doesn't even have it up on theirs yet. )

690 lbs 100,000 BTU 4 cu ft firebox able to take 26 inch wood. Just waiting to chomp into a woodpile!. That's about 30 fills per cord. Two firings a day would add up fast.

Oh how I would love to build a house with that puppy right in the middle of it. WHOOHYA. Too bad my new house days are over. And the concrete pillar under it in the basement would take up major space.

Wow! That's one big heating beasty! I don't know if I really like the looks tho. It's kind of square, needs some curves on it. Also takes 8" pipe. What kind of noncat burn system does it have? Burn tubes and baffle, or something similar to everburn?

 

[BrotherBart]

Well for an out of the box solution, practically a masonry heater on its own you could also grab a Hearthstone Equinox (Big hat tip to Tom for featuring it on his very informative site when Hearthstone doesn't even have it up on theirs yet. )

690 lbs 100,000 BTU 4 cu ft firebox able to take 26 inch wood. Just waiting to chomp into a woodpile!. That's about 30 fills per cord. Two firings a day would add up fast.

Oh how I would love to build a house with that puppy right in the middle of it. WHOOHYA. Too bad my new house days are over. And the concrete pillar under it in the basement would take up major space.

Wow! That's one big heating beasty! I don't know if I really like the looks tho. It's kind of square, needs some curves on it. Also takes 8" pipe. What kind of noncat burn system does it have? Burn tubes and baffle, or something similar to everburn?

Go to the bottom of this page on Tom's site and tell me what about the liner installation would not be legal in Elkville, Massachusetts. :cheese:

http://www.chimneysweeponline.com/cequinox.htm

 

[Todd]

Well for an out of the box solution, practically a masonry heater on its own you could also grab a Hearthstone Equinox (Big hat tip to Tom for featuring it on his very informative site when Hearthstone doesn't even have it up on theirs yet. )

690 lbs 100,000 BTU 4 cu ft firebox able to take 26 inch wood. Just waiting to chomp into a woodpile!. That's about 30 fills per cord. Two firings a day would add up fast.

Oh how I would love to build a house with that puppy right in the middle of it. WHOOHYA. Too bad my new house days are over. And the concrete pillar under it in the basement would take up major space.

Wow! That's one big heating beasty! I don't know if I really like the looks tho. It's kind of square, needs some curves on it. Also takes 8" pipe. What kind of noncat burn system does it have? Burn tubes and baffle, or something similar to everburn?

Go to the bottom of this page on Tom's site and tell me what about the liner installation would not be legal in Elkville, Massachusetts. :cheese:

http://www.chimneysweeponline.com/cequinox.htm

No block off plate! :lol:

 

[Jade]

But there are also a number of "in-betweens" - such as using the built-in units from Magnum and Kozy and surrounding them with masonry. Take some design hints from the pros and build the whole thing inside the house envelope......the masonry will complement the heat. This can be done to a lesser degree with zero clearance built-ins - surround them with some mass!

When you referred to the Magnum and Kozy built-in units, are these the Kozy 234 & 432, and Magnum Masonry? Then are the zero clearance built-ins the Kozy 231, 241 & Z42 and the Magnum ZC?

Also, why “to a lesser degree” with the zc built-ins? How is that difference quantified? What is the difference?

 

[Gooserider]

But there are also a number of "in-betweens" - such as using the built-in units from Magnum and Kozy and surrounding them with masonry. Take some design hints from the pros and build the whole thing inside the house envelope......the masonry will complement the heat. This can be done to a lesser degree with zero clearance built-ins - surround them with some mass!

When you referred to the Magnum and Kozy built-in units, are these the Kozy 234 & 432, and Magnum Masonry? Then are the zero clearance built-ins the Kozy 231, 241 & Z42 and the Magnum ZC?

Also, why “to a lesser degree” with the zc built-ins? How is that difference quantified? What is the difference?

Not sure about the differences between the models that you are mentioning, but I would not expect a ZC unit to make a good "fake MH" because of it's inherent design. The ZC is designed very carefully NOT to pass heat through it into the surrounding structure, thus defeating the point of adding the thermal mass. A ZC also usually includes some level of venting or other air circulation intended to further cool it's exterior, again defeating the purpose of the design.

You probably would get some heat storage regardless, so I would expect a ZC with a brick surround to do better than one with a wooden surround, but no way would it function like an MH.

Gooserider