Masonry heaters...

Kevin K · February 12, 2007, 10:30:33 AM

Does anyone have one?

If so, can you provide some input?

Thanks!

Dave Shepard · February 12, 2007, 10:57:15 AM

I don't have one, but I toured a house last fall that has one, and the entire house is heated off of it. The house has four bedrooms upstairs and a fairly open layout downstairs. The total wood usage is about 3+/- cords per year. The house is probably 1800 sq. feet. There is also a wood fired cookstove in the kitchen, which is used spring and fall to heat the house, it gives off just enough heat to get through the cold nights, but is out during the day, when there is plenty of solar gain. They are an investment, but I think they seem to be well worth it. I am guessing they are probably the same investment as an outdoor wood boiler, with much less wood consumption. The masonry heater is also more enjoyable, IMO.

Dave

Kevin K · February 12, 2007, 11:18:51 AM

Thanks for the reply.

Where was this house located?

I live 3 hours North of Fargo.

Raphael · February 12, 2007, 11:32:37 AM

They are a great way to go if you can afford them.
Unfortunately they don't count as heat in this state...

Dave Shepard · February 12, 2007, 04:18:43 PM

Kevin, the house is located in Western Mass, and is a private residence.

Raphael, do you mean as far as getting a loan? I would assume otherwise, how you heat your house is your business. My friend had the same problem with an outdoor boiler and the bank.

Dave

Jim_Rogers · February 12, 2007, 07:14:41 PM

There is a masonry heater association.
There is all kinds of info there, and I think a list of masons who know how to make them.
Try doing a goggle search and you should be able to find it.
I had the web page address once but I've lost it.

Jim Rogers

Dan_Shade · February 12, 2007, 07:17:58 PM

is a masonry heater the setup where the "chimney" snakes around to heat up a bunch of bricks? before letting the smoke out?

Stumpkin · February 12, 2007, 07:49:57 PM

The Masonry Heater Assn. of N.A and Maine Wood Heat are good sources of masonry heater information. Maine Wood Heat is the business of Albert Barden who has written books on masonry heater construction and also offers workshops. I attended a presentation by Mr. Barden at a TF Guild conference and was very impressed with his ideas. Tom

ohsoloco · February 12, 2007, 07:54:43 PM

When I was looking into building a house (finally just bought one) I really wanted to go with a masonry heater. Got lots of info. from the MHA in the link that Sumpkin posted. Also looked at Temp-cast masonry heaters at http://www.tempcast.com/index.html

I'm pretty sure Temp Cast is the place that can get you in touch with current owners of the heaters so you can check them out...kind of like our sawmill sponsors do

Kelvin · February 12, 2007, 08:38:01 PM

Timber framing always seems to ge with masonary heaters. What i don't quite understand is why they cost so much money? I guess its the same reason timber frames cost so much, its the elite that buy this stuff 99% of the time. I built my own timber frame from scratch with no background in it, and if that is what you are doing, i don't see what the mystery would be in building a masonary heater or finding a local mason to follow the design principles. I've always found it humrous that people think some sort of magic is going on inside them. Its called thermal storage. "Soapstone has unique properties that make it ideal for costing one million dollars" Why is soapstone the "in" thing? How does it differ in thermal mass than say concrete, field stone, or any other rock? I guess it cuts and polishes easy. I know that a masonary heater has a more complex design than say a Rumford type fireplace, but there are people all over europe who build them as usual fare. I'm sure any competant mason could follow the design for you without having to import the stuff from Sweden. In fact, thermal mass is quite easy to design into any wood fired system, but its not magic. You can't heat your house all day unless you have a super insulated to go with that heater. The btu's you burn have to be equal to what is needed for the home. It just holds the heat that normally runs up the chimney fast. Its not magic. If you are building a timberframe, either look into building one yourself, or hire a local mason to build you one and save oh, about $6k.

Also, my buddy built himself a wood boiler as well. He had accumulated the steel, all the pumps, and radiators for free, so no cost to him at all. No mystery there either. Just a water jacket and circulating pumps. I just bought 12 4x8 sheets of scrap 1/8" steel for him to build me a copy for about $500. Gotta get the pumps and make the tubing for the underground supply. I will heat my house, shop, kiln, and barn with scrap wood from my woodmizer sawmilling. These to are a ripoff because they aren't bought in large quantities yet, and people think they are complicated.

Dave Shepard · February 12, 2007, 09:10:29 PM

Dan, yes, that is what a masonry heater is.

Kelvin, you are absolutely right about building your own. The main reason I see that the commercial units cost what they do is becuase the companies have done the research and trial and error to come up with a salable product. Also they have to deal with the overhead of commercial operations, profit, etc. The masonry heaters that I have seen have special cast fireboxes, it is a little more than just laying up brick.

Also, as you must have found out, timberframes don't have to be for just wealthy people, which is a common misconception.

Dave

Raphael · February 13, 2007, 02:11:35 AM

What I mean by "they don't count as heat" is you can't get a CO in this state with only wood heat in your house. So it's an issue if you are borrowing money to build or planning on selling.
Depending on how a construction loan is written you may be in default if you fail to produce a CO at the end of the construction period, which means good bye house and property. Fortunately with our loan I don't need a CO, as long as I keep making the payments the bank will be happy.

beenthere · February 13, 2007, 02:18:11 AM

Raphael
What is a "CO" ???

Raphael · February 13, 2007, 02:24:12 AM

sorry... CO = Certificate of Occupancy
Basically a piece of paper that says your structure meets or exceeds building codes.

beenthere · February 13, 2007, 02:28:23 AM

Gotcha. Just couldn't come up with dat. Figured something like it tho. Thanks

Don P · February 13, 2007, 08:19:20 AM

We call it the "final" too.

I have a pretty good book on masonry heaters "The book of masonry stoves" David Lyle.
He does explain history and some theory. As Kelvin points out it ain't rocket science, but it is more than just stacking up mass. There are some rules of thumb to make any fireplace draw well, I think I've seen one useable Rumford in my life

I'm watching another go up in the neighborhood thats prolly gonna smoke. The efficiency comes into play by extracting more heat from the smoke. Burning the same number of logs more heat stays within the building with these as opposed to a greater portion going up the flue with most wood burning appliances. They take a different burning mentality, most airtight guys are going to clog one or drive themselves crazy :D. They work on short duration flash fires to heat the mass rather than a long slow smolder.

Dave Shepard · February 13, 2007, 11:30:14 AM

Don P, you mentioned short duration fires. The heater I saw burned 50-70 pounds of wood as fast as you could get it to burn, which led to a very clean, hot burn. This was enough to heat the house for something like 20 hours. I think that the cleanliness of the burn is also an environmental advantage over running a wood stove choked down by dampers.

Dave

Thomas-in-Kentucky · February 13, 2007, 07:28:25 PM

I love this thread, even though I think it's too late for me to incorporate a masonry heater in my house.

Don, are you skeptic of rumfords, or just saying that most masons don't build them correctly? Reason I'm asking is that I've already bought a rumford kit and a bread oven kit from Superior Clay but haven't started on either. The Rumford kit includes the throat, the damper, correct flue liners, smoke chamber, and firebrick. I sure hope it works! Supposedly, if you follow their directions and the throat fits on top of the firebox that you've built, then it will work. My friend has one (from the same company, but a 30 or 36" model instead of the 48" that I got) and it works great.

Also, thinking about building my own outdoor (or indoor) wood furnace to produce hot water for my radiant heat floor. I too cannot understand why they should cost so much. I'm currently heating the unfinished house with a barrel stove that I picked up at the scrap yard for scrap price. (actually, we're just burning an armload of wood per day on the days we work to take the edge off) and it keeps the house in the 40's while it has been between 0 and 20 degrees outside for nearly two weeks. I am amazed at the simplicity of the barrel stove, and searching for the water jacketed analog of it. (couldn't you just put a coil of pipe around a barrel stove if you weren't sure of your ability to produce watertight welds? or buy a watertight tank and weld a firebox to it?)

Also wondering if one couldn't put waterpipes in the chimney of my rumford setup and feed that to the radiant heat floors? (But I guess cold flue temps = more creosote build up)

-Thomas

treenail · February 13, 2007, 07:36:39 PM

Several years ago, I had a custom sawing job / house construction job that I did all of the carpentry work for on a 3000 sf house in central New Hampshire that had been designed around a masonry heater. Returned a few weeks ago to do a small job there during this really frigid weather, and the place was heated very nicely. Also had the opportunity to install an outdoor boiler in Vermont last year, and as far as price comparisons go, the masonry heater, which was a tempcast base , was considerably more expensive when all was said and done. If the homeowner totally constructed the masonry, perhaps they might have been on an equal par , costwise. Both systems performed equally great though. As far as asthetics go, the masonry certainly added eye appeal as well as financial equity in the real estate values.

Don P · February 13, 2007, 10:22:42 PM

Thomas,
Most of the ones I've seen were not built well. I'm no mason but I believe Count Rumford laid out a set of ratios for not only the firebox that you see but the throat and smoke chamber area as well. I've never worked around one of the Superior Clay models but I understand they are dimensioned correctly.
If you look in some of Stickley's drawings you'll often see a metal hood over the fireplace. We mounted something similar on one that spilled alot of smoke.

The Count was an interesting character if you've never studied him.

Closest I came is we have a footing capable of supporting a masonry heater, with a 200 lb woodstove on it. I do agree with Dave, a fast oxygen rich fire is a cleaner burn. Soapstone was quarried in the mountains around here and used for chimney construction in pioneer days. I have a few old soapstone bricks around here somewhere.

Insurance was our motivator to put in a backup heater, we installed a monitor K-1 direct vent. It does a good job on our 1500sf. We've been thru about 50 gallons of fuel and maybe a half cord so far this winter. Kinda hard to guage my wood use, a carpenter brings his mistakes home ;D.

If you rig anything with water make certain it is vented and cannot build steam pressure. A relatively small amount of superheated water upon escaping can become more cubic feet of steam than a house can contain. Kinda in the same vein as a relatively small quantity of dynamite ;)

Don_Papenburg · February 13, 2007, 11:27:02 PM

Thomas In KY , How do you plan to use the SC bread oven? I looked into it a few years ago . It was not designed to retain heat and the size was a bit on the small side. Look into the Alan Scott -Ovencrafters website . I changed my mind. You may or not.

barbender · February 14, 2007, 12:22:06 AM

I bought the book by David Lyle, and I like the idea and theory of the masonry heaters, but they seemed like way too much money to me. I'm with Kelvin, I don't understand why they cost as much as they do. If they've been building them in Europe for 300 years it seems a guy should be able to make some clay bricks out in the back yard and whatever other materials a guy needs. Oh, Kelvin, don't plan on heating with an outdoor boiler with just slabs of the woodmizer unless you do a LOT of sawing, they eat guite a bit of wood. I just installed one this fall and she gobbles a bunch of wood. I think the main benefit to the outdoor boilers is you can burn wet junk wood that you could never burn in a fireplace. I've cut live frozen trees down and thrown them in, filled the stove right up with nothing but wet wood, and it burns just fine.

Don P · February 14, 2007, 12:59:50 AM

I agree with you on being able to build something satisfactory at home. I thought about scaling from some of the pics in the book. I have one seriously warped stove that I surrounded with firebrick the did a pretty decent job of storing heat. The metal in flame contact and with no cooling on the outside wasn't up to the job but I've wondered about a firebrick lined and covered welded up stove. Pieces of angle iron could act as tracks to slip brick into.

Raphael · February 14, 2007, 03:49:28 AM

My thermal mass concept is roughly a half ton of field stone facing on the chimney directly behind the wood stove. Once it soaks up enough heat it should keep things comfortable overnight save me a little wood.

Thomas-in-Kentucky · February 14, 2007, 09:24:38 AM

Don P:
Thanks for the clarification on the smoking rumfords. SC has sold a lot of these kits and I think (hope?!) they have the ratios right. They have a great web site on Rumfords that has lots of information for self builders, and much of it is not even specific to their products. Gotta love web sites like that... they give you the information before you spend a dime! Look at Rumford dot com or google "superior clay rumford" The wife bought me a book on Count Rumford for Christmas - yes he was a very interesting character. Only thing not to like is that he sided with the British during the revolution!

Don_Papenburg:
From reading through their stuff, it looks like SC has changed the design of their bread ovens some over the past few years. They presently offer three sizes, and we decided to go with the larger 36" model because anything smaller looks like it has to be heated with a fire and the fire removed before cooking - relying then on thermal mass like you mention. I understand that using the thermal mass to cook with is a typical way to use the ovens, but I like playing with fire, so how much fun would it be to have to put the fire out before cooking?! The SC oven is a shell onto which you add parging, or optionally, it looks like you could add firebrick and then parging to get more thermal mass. Do you have a bread oven? I really don't know anymore about them other than the fact that I have the SC kit sitting in my barn right now waiting for warmer weather before we will start the chimney, etc. The decision to go with their kit as opposed to others was biased largely by the fact that I was already buying the Rumford kit from them and could kill two birds with one stone. Too late to change my mind, but if you have suggestions (like whether I should add the add'l thermal mass) then its not too late for that!

For anyone wondering, the 48" Rumford kit and the 36" bread oven kit together cost just under $5,000 including firebrick, high temp mortar, refractory, damper for the rumford, door for the bread oven, and 24+ feet of flue liners for both. Smaller models of both would have cost a lot less - the big difference in price was a jump up to a 16x20 flue liner required for the 48" Rumford. Those flue liner segments were over $60 each and I had to buy 14 of them. Gulp. Even though the price seems quite high, it is still much less than an outside wood furnace. (not that they perform the same tasks - I'm just trying to rationalize the Rumford and bread ovens!) I must still buy cinderblock, and I'll be facing the whole deal with siltstone (fine grained sandstone) from my property. The thermal mass will be quite large (5' x 7' x 32') and is located in the center of my house, not up an exterior wall.

Quote"Soapstone has unique properties that make it ideal for costing one million dollars" - Kelvin

I read that quote to my wife last night and we busted out laughing. Too true. We have a friend who will have nothing in his kitchen but soapstone because he thinks granite and marble looks manmade! Huh!? He also touted the machinability of soapstone for DIYers, but when it came time to cut the opening for his sink, he chickened out and took it to a counter fabricator. Great friend, nice guy - I just don't understand he hangup with soapstone. (have to say that in case he googles soapstone and finds this post in 5 years!)