Masonry Heaters

[Todd]

Do masonry heaters have a damper you need to close after that 2 hour firing to keep the heat in?

Yes.

Aye,
Marty

So can that be a pita at times waiting around to close the damper, or can you leave it open and go about your buisness?

 

[mainemac]

The masonry, about 3 - 4 tons of it (yup) from the firebox to the chimney, absorbs the intense combustion heat at about 1800* F or so in the firebox allowing only about 275* - 300* F out the chimney. This absorbed heat is then gently released as radiant heat to the room over the next 20 hours or so.

Having a fire like this with morning coffee and then again (maybe 3 fires/24 hours when it’s single figures outside, maybe a dozen/year) with a sundowner provides total ambience for us since wife and I rarely are here most of the day. More than 3 fires would serve no purpose.




HOLY COMBUSTION BATMAN
That sounds fantastic. Super efficient burn less lots of warmth and spectacular viewing . I want one!

Tom

 

[Martin Strand III]

Do masonry heaters have a damper you need to close after that 2 hour firing to keep the heat in?

Yes.

Aye,
Marty

So can that be a pita at times waiting around to close the damper, or can you leave it open and go about your buisness?

As long as you know what you're doing and how it works, you can do whatever you want. Minimal planning is involved.

If it's blustery and very cold, you make it a point to close the damper when the coals are almost gone. This conserves heat.

If the weather is moderate, the house is warm or you find yourself leaving before you planned, it doesn't matter if the damper is left open and some heat escapes. The great thermal mass provides enough "umph" (heat output w/o a fire) to prevent back drafting with the damper left open. This last feature is a relatively undiscussed safety feature of a MH unlike metal stoves. Leaving the damper open just cools the unit some. This is remedied with the next fire and also is a great adjustment to have when cooking in the bake oven..

Aye,
Marty
Grandpa used to say, "One man's pita is another man's pie."

 

[killick]

My friend's kachelofen has no damper.I believe the design is less complex than the Temp Cast units. It works fine on substantially less wood than the wood stove was using and almost no emissions and creosote. Here in Nova Scotia he only fires twice a day in the coldest weather.

Earl

 

[Jersey Bill]

I just fired up my masonry heater. Its been a work in progress for over a year.
I bought a kit from Main Wood heat, and found my own local reclaimed brick to build the shell with.
I laid every brick myself

 

[killick]

Sweet! Is that piping for a water jacket I see on the side? What's the weight. Nice looking job Bill let us know how it works out.

Earl

 

[Rockey]

If I built one right on my basement concrete floor would it require a new footing/footer to be dug to support the weight?

 

[Jersey Bill]

there is no water jacket inside the stove, those are temperature gauges. 1 is deep into the smoke port, the other is shallow in the core.

The slab and back wall has radiant tubes in it. When the stove is off, the panels radiate into the room, and when the stove is on, the water will take heat away to the rest of the house.

As far as the weight on a slab on grade, the easy answer is to ask a structural angineer. It really depends on the type of soil. I have about 50,000 lbs right there. The stove, mantle, and hearth, foundation, and footing each weight about 10k each.

If you just had the stove, say, it has a footprint of about 8 sq ft, then the bearing load is 1250 lb/sqft or 9 lb/sqin.

Is there on loam or bedrock in your basement ?

b

 

[Renovation]

My TempCast is here:

https://www.hearth.com/gallery/pics/fireplaces/source/tilestove.html

Aye,
Marty

Thanks for the photo Marty. It's a lovely install, and your integrated wood storage is neat.

 

[weatherguy]

Thats beautiful, some day I hope to have one

 

[Renovation]

I get a similar effect with my basement install of a traditional cast iron stove. It heats up several thousand pounds of cement block and masonry chimney.

That's very clever. I also think about adding thermal mass to a traditional stove. Can you share any photos?

 

[Renovation]

Do masonry heaters have a damper you need to close after that 2 hour firing to keep the heat in?

Yes.

Aye,
Marty

Thanks for the great info, Marty.

Anyone ever heard of automating the damper closure, perhaps with a thermostat on the firebox?

 

[Martin Strand III]

I just fired up my masonry heater. Its been a work in progress for over a year.
I bought a kit from Main Wood heat, and found my own local reclaimed brick to build the shell with.
I laid every brick myself

Bill:

That's a beauty! Congratulations on your hard work.

Some questions:

1. How did you separate the core from the brick veneer to prevent cracking?
2. Do you have a clean out in the back of the unit?
3. Does your flame path go through or around your bake oven?
4. Do you have outside air?

Thanks.

Aye,
Marty

 

[Sisu]

Masonry stoves have been around for hundreds of years in Scandinavia, where the winters are long and cold and wood was not always plentiful. I was visiting relatives in Finland in August and these are some of the "Finnish" masonry stoves I saw. Some are very old, others are new. However, they are all extremely efficient. I estimated I would probably burn 1/2 to 1/3 of the wood I burn now, in a masonry stove compared to my woodstove insert. Even though the cost of the masonry stove seems high, burning less wood equals less sweat equity.

I don't know why they are not promoted more in North America. Maybe because we tend to have an abundance of wood, so burning 24/7 is not frowned upon. If I were building a house for myself, I would probably install a masonry stove.

 

[DBoon]

Jersey Bill - great install, really, really nice. Congratulations!

Sisu - thanks for all the photos.

I suspect that masonry heaters are not more popular in the states due to the large up-front cost. Americans typically don't like large up-front costs with the promise of later payback since they never imagine that they will be in their home long enough to benefit from the payback, and the next homeowner is likely to value that expensive masonry stove at $0 when they look to buy your house.

 

[agartner]

Awesome looking MH, I'm wicked jealous. I want one in my house. Also seems like you did it fairly economically by doing it yourself and creatively obtaining the brick facing. Are you an experienced mason, or was this your first time out laying stonework? Just curious if something like this could possibly considered as a "diy" project.

 

[dvellone]

Ive got a close friend that heats with one and seeing his in action has convinced me to put one in the new house I'm planning on starting this Spring. He lights one fire/day during the heating season and the heater is always hot to the touch. Nice even heat and in a tight and well-insulated house it performs beautifully. He did build his himself and though I can't remember his total materials investment I do remember thinking that it wasn't bad at all. It depends a lot on the masonry supply. I've been in the masonry business for many years and I've seen a great variance in masonry supplies depending on the dealer.

 

[Martin Strand III]

MH wannabees, educate yourselves here

(broken link removed)

for the history and advantages masonry heaters enjoy over their metal wood burning cousins.

This unit (TempCast; there are others) can be assembled as a DIY to save on cost. I elected not to tackle it as some core refractory pieces weigh in excess of 270 lbs. Despite the higher cost for me contracting the job to professionals, my payback comes from having my own woodlot. Now in my 7th heating season, the TempCast remains supremely simple, enjoyable, effective and dependable.

Intelligent DIY'ers pay attention to the many details (support, thermal expansion of core vs facade, anchoring doors, facade thickness,
outside air, cleanouts, damper control, chimney, etc,etc) in order to remain happy down the road. Newly constructed DIY units have not
withstood the test of time. Well made units last generations.

I agree with a previous post that many will not go this route due to the (relative) high initial cost. Short term thinkers want it cheap and want it now. To those, there is a different path available.

Aye,
Marty

 

[Sisu]

MH wannabees, educate yourselves here

(broken link removed)

for the history and advantages masonry heaters enjoy over their metal wood burning cousins.

This unit (TempCast; there are others) can be assembled as a DIY to save on cost. I elected not to tackle it as some core refractory pieces weigh in excess of 270 lbs. Despite the higher cost for me contracting the job to professionals, my payback comes from having my own woodlot. Now in my 7th heating season, the TempCast remains supremely simple, enjoyable, effective and dependable.

Intelligent DIY'ers pay attention to the many details (support, thermal expansion of core vs facade, anchoring doors, facade thickness,
outside air, cleanouts, damper control, chimney, etc,etc) in order to remain happy down the road. Newly constructed DIY units have not
withstood the test of time. Well made units last generations.

I agree with a previous post that many will not go this route due to the (relative) high initial cost. Short term thinkers want it cheap and want it now. To those, there is a different path available.

Aye,
Marty

I agree. How much wood do you burn a year?

 

[begreen]

I've always admired the Europeans for using mass to effectively store and release heat from their stoves. They have taken it to a high artform.

Marty, could you tell us a bit about the difference in running a masonry heating system in the different seasons? Is it as simple as deciding whether it is a one, two or three fire day?

 

[Martin Strand III]

MH wannabees, educate yourselves here

(broken link removed)

for the history and advantages masonry heaters enjoy over their metal wood burning cousins.

This unit (TempCast; there are others) can be assembled as a DIY to save on cost. I elected not to tackle it as some core refractory pieces weigh in excess of 270 lbs. Despite the higher cost for me contracting the job to professionals, my payback comes from having my own woodlot. Now in my 7th heating season, the TempCast remains supremely simple, enjoyable, effective and dependable.

Intelligent DIY'ers pay attention to the many details (support, thermal expansion of core vs facade, anchoring doors, facade thickness,
outside air, cleanouts, damper control, chimney, etc,etc) in order to remain happy down the road. Newly constructed DIY units have not
withstood the test of time. Well made units last generations.

I agree with a previous post that many will not go this route due to the (relative) high initial cost. Short term thinkers want it cheap and want it now. To those, there is a different path available.

Aye,
Marty

I agree. How much wood do you burn a year?

I've averaged about 3 full cords from September to March.

Aye,
Marty
Grandma used to say, "Sometimes less is more."

 

[Sisu]

MH wannabees, educate yourselves here

(broken link removed)

for the history and advantages masonry heaters enjoy over their metal wood burning cousins.

This unit (TempCast; there are others) can be assembled as a DIY to save on cost. I elected not to tackle it as some core refractory pieces weigh in excess of 270 lbs. Despite the higher cost for me contracting the job to professionals, my payback comes from having my own woodlot. Now in my 7th heating season, the TempCast remains supremely simple, enjoyable, effective and dependable.

Intelligent DIY'ers pay attention to the many details (support, thermal expansion of core vs facade, anchoring doors, facade thickness,
outside air, cleanouts, damper control, chimney, etc,etc) in order to remain happy down the road. Newly constructed DIY units have not
withstood the test of time. Well made units last generations.

I agree with a previous post that many will not go this route due to the (relative) high initial cost. Short term thinkers want it cheap and want it now. To those, there is a different path available.

Aye,
Marty

I agree. How much wood do you burn a year?

I've averaged about 3 full cords from September to March.

Aye,
Marty
Grandma used to say, "Sometimes less is more."

Very impressive! I burn about 5 bush cords in a year in a 1500 square foot bungalow. I have improved the insulation, sealing etc. but need to burn 24/7 once the temps start approaching 0 degrees Celsius. I often wondered if I could convert my basement masonry fireplace into a masonry heater.

 

[Martin Strand III]

I've always admired the Europeans for using mass to effectively store and release heat from their stoves. They have taken it to a high artform.

Marty, could you tell us a bit about the difference in running a masonry heating system in the different seasons? Is it as simple as deciding whether it is a one, two or three fire day?

Evidence exists that rock, in various formations, has been used to hold heat from a fire dating back 35,000 ---> 100,000 years ago (D Lyle, Book of Masonry Stoves). As time marched on, sophistication in the designs (cro magnon/neanderthal R&D) also evolved into the units we enjoy today (TempCast, Biofire, Tulikivi, Heat-Kit, Canadian Kachelofen, Maine Wood Heat, etc).

Burning in a masonry heater differs from doing the same in a metal stove. The heating/cooling cycle is stretched out significantly and surface masonry to touch stays below 160* F (no fried dust) - quite different from metal stove surface temps. Because of the MH's ability (thermal mass) to store (bank the heat) the heat generated by the fire (masonry has moderate heat conductivity; metal has high heat conductivity) and release it slowly for hours, fewer fires (less wood) are required per 24 hrs.

Some anticipation of incoming weather is helpful since, once fired (some units burn up to 60 lbs fuel charge which generates perhaps 350,000 BTU's), the heat conducts into the masonry mass and is released into the room like it or not. So, in the shoulder seasons, I burn a smaller fire (maybe 20 lbs of wood) than an average fire in hard winter. Then, depending on outside temps, one full 50 lb load works nicely for 24 hrs with outside temps in the high 30's or so. If it's nippy in the 20's, with a cold northern wind, one AM fire (with coffee) and one PM fire (with a sundowner) works out nicely. The Mfg advises not more than three fires (one every 8 hrs) in 24 hrs. This is infrequent for me; only when the temp dips into the single figures.

Aye,
Marty

 

[Martin Strand III]

[quote SNIP
Grandma used to say, "Sometimes less is more."[/quote]

Very impressive! I burn about 5 bush cords in a year in a 1500 square foot bungalow. I have improved the insulation, sealing etc. but need to burn 24/7 once the temps start approaching 0 degrees Celsius. I often wondered if I could convert my basement masonry fireplace into a masonry heater.[/quote]

These thermal mass heaters emit almost pure radiant heat; conductive heat is secondary. Therefore, they work best in open floor plans. So, I'd put a hi output convection heater in my basement (I did), not a MH, which also needs a stalwart foundation on undisturbed earth - tough if not new construction.

Aye,
Marty

 

[Todd]

I love the looks of those massive heaters but wouldn't it get tiring building a fire 2 or maybe even 3 times per day for 3-4 months of the year? I haven't had to light a match in my Fireview for over 2 weeks and I reload 2 or 3 times per day without having to use kindling. I think I would get tired of chopping kindling every day. I also don't think I could do any better at firewood savings than the 3 cords I'm burning now to heat my 2000 sq ft.