Masonry Heaters

[Martin Strand III]

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.

You're not comparing apples to apples. There's a difference.

The rule with a sizeable MH is 2 fires/day. Three fires is the exception. Loading the firebox takes 2 minutes. No kindling, no kidding, with dry hardwood. Fire starts no problem with just a lil' home made fire starter in a hot fire box. These 2 fires burn HOT (aka clean) with wide open air.

With only 2 - 3 loads/day heating your house, you are choked down on air burning slow (aka dirty).

What you like, your neighbors might not...

Aye,
Marty

 

[dvellone]

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.

I thought the same but if your house is real well insulated you might not need to keep a fire going in the wood stove all day long anyway. My small house is well insulated and unless the temperatures are below zero I only need to light a morning fire and sometimes an evening fire in my castine. Any more and the the temperature becomes uncomfortable. With the stove I have a bit of a swing in temperatures. A friend of mine with a masonry heater has a nice constant temperature with one fire every morning - one at night only during the deepest cold. The heater's draft is unbelievable and his kindling is much larger than mine and he needs only a few pieces then the bigger splits which are also on the small side. The fire quickly and easily roars to life. I think it depends on what the layout and efficiency of your home is like that might help to determine what kind of heater works best for you as well. As far as being tiresome I'll admit that there are times I wish I could just keep a fire going rather than starting over each time, but if the fire I started every morning got that nice big mass of masonry nice and hot I might not mind it so much

 

[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.

You're not comparing apples to apples. There's a difference.

The rule with a sizeable MH is 2 fires/day. Three fires is the exception. Loading the firebox takes 2 minutes. No kindling, no kidding, with dry hardwood. Fire starts no problem with just a lil' home made fire starter in a hot fire box. These 2 fires burn HOT (aka clean) with wide open air.

With only 2 - 3 loads/day heating your house, you are choked down on air burning slow (aka dirty).

What you like, your neighbors might not...

Aye,
Marty

Ok, I guess you could just throw a super cedar in there with a few smaller splits, that would eliminate kindling.

I wouldn't say my stove is any more dirty burning than your masonry heater. It was designed to burn clean low and slow. You have smoke at start up just like the rest of us, don't you?

 

[Burn-1]

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

Aye,
Marty

Three cords in a ~9,000 degree day climate. Not too shabby.

 

[Dakotas Dad]

Evidence exists that rock, in various formations, has been used to hold heat from a fire dating back 35,000 ---> 100,000 years ago
Aye,
Marty

And to think, I am happy with a 8 hour burn.



:cheese:

 

[Renovation]

Evidence exists that rock, in various formations, has been used to hold heat from a fire dating back 35,000 ---> 100,000 years ago
Aye,
Marty

And to think, I am happy with a 8 hour burn.



:cheese:

Thanks DD, my Pepsi Max just went through my nose. Yes, that 65,000 year fire must have been impressive, and 35,000 years is an impressive time to hold heat!

o/` "Give me that old-time masonry, if it was good enough for Neanderthals, it's good enough for me!" o/`

Apologies, I just couldn't help myself.

Humor aside, I think masonry stoves are very cool. Those rocket stove earthen bench heaters are neat too.

 

[Martin Strand III]

SNIP

I wouldn't say my stove is any more dirty burning than your masonry heater. SNIP

I would.

I'd say your wood burning metal stove is, at best (Phase II?), about twice as dirty putting out about 7.3 Grams/24 hrs of PM-10 particles compared to 2.8 Grams/24 hrs in a masonry heater. Not my opinion, just published data.

Try googling "Particulate emissions wood burning stoves" and ratchet up on some basic wood burning facts.

Aye,
Marty

 

[Todd]

SNIP

I wouldn't say my stove is any more dirty burning than your masonry heater. SNIP

I would.

I'd say your wood burning metal stove is, at best (Phase II?), about twice as dirty putting out about 7.3 Grams/24 hrs of PM-10 particles compared to 2.8 Grams/24 hrs in a masonry heater. Not my opinion, just published data.

Try googling "Particulate emissions wood burning stoves" and ratchet up on some basic wood burning facts.

Aye,
Marty

Looks like your the dirty one Marty. My stove comes in at 1.3 grams, more than twice as clean as your heater. BTW I don't have a metal stove, it's more like a minny masonry heater. Here are some facts for you to look over.

(broken link removed)

 

[Martin Strand III]

SNIP

I wouldn't say my stove is any more dirty burning than your masonry heater. SNIP

I would.

I'd say your wood burning metal stove is, at best (Phase II?), about twice as dirty putting out about 7.3 Grams/24 hrs of PM-10 particles compared to 2.8 Grams/24 hrs in a masonry heater. Not my opinion, just published data.

Try googling "Particulate emissions wood burning stoves" and ratchet up on some basic wood burning facts.

Aye,
Marty

Looks like your the dirty one Marty. My stove comes in at 1.3 grams, more than twice as clean as your heater. BTW I don't have a metal stove, it's more like a minny masonry heater. Here are some facts for you to look over.

(broken link removed)

If you burn a Woodstock Keystone (your newest stove?), you produce 1.9 Grams/Hr.
http://www.woodstove.com/index.php/keystone

In a day, take 24 X 1.9 to compare to my above figures.

Not apples and apples yet.

Aye,
Marty

 

[Martin Strand III]

Metal stoves with panels of granite, marble, rock or soapstone do not come close to being "mini" masonry heaters.

A metal/masonry combo stove weighing in at 600 or even, rarely, 800 lbs simply cannot store the heat of a true thermal mass masonry heater tipping the scales at 7500 lbs.

To be clear, read the Masonry Heater Association's definition of a masonry heater:

"MHA Masonry Heater Definition

A masonry heater is a site-built or site-assembled, solid-fueled heating device constructed mainly of masonry materials in which the heat from intermittent fires burned rapidly in its firebox is stored in its massive structure for slow release to the building. It has an interior construction consisting of a firebox and heat exchange channels built from refractory components.

Specifically, a masonry heater has the following characteristics:

- a mass of at least 800 kg. (1760 lbs.),

- tight fitting doors that are closed during the burn cycle,

- an overall average wall thickness not exceeding 250 mm (10 in.),

- under normal operating conditions, the external surface of the masonry heater, except immediately surrounding the fuel loading door(s), does not exceed 110 C. (230 F.),

- the gas path through the internal heat exchange channels downstream of the firebox includes at least one 180 degree change in flow direction, usually downward, before entering the chimney,

- the length of the shortest single path from the firebox exit to the chimney entrance is at least twice the largest firebox dimension,

(passed unanimously at 1998 MHA Annual Meeting, June 8, 1998)"

Even chopping off a major portion of the numerical requirements above, does not make a metal/masonry stove the real deal.

They are engineered, built and function too differently to compare.

Aye,
Marty

 

[Martin Strand III]

SNIP

I wouldn't say my stove is any more dirty burning than your masonry heater. SNIP

I would.

I'd say your wood burning metal stove is, at best (Phase II?), about twice as dirty putting out about 7.3 Grams/24 hrs of PM-10 particles compared to 2.8 Grams/24 hrs in a masonry heater. Not my opinion, just published data.

Try googling "Particulate emissions wood burning stoves" and ratchet up on some basic wood burning facts.

Aye,
Marty

Looks like your the dirty one Marty. My stove comes in at 1.3 grams, more than twice as clean as your heater. BTW I don't have a metal stove, it's more like a minny masonry heater. Here are some facts for you to look over.

(broken link removed)

If you burn a Woodstock Keystone (your newest stove?), you produce 1.9 Grams/Hr.
http://www.woodstove.com/index.php/keystone

In a day, take 24 X 1.9 to compare to my above figures.

Not apples and apples yet.

Aye,
Marty

Woops. My mistake. Sorry.

The 1.3 per hour wins. Squeeky clean burning, congrats.

The others (7.3 and 2.8) were per hour, not per 24 hours.

The thermal mass statement stands.

That's my story and I'm sticking to it.

Aye,
Marty

 

[Martin Strand III]

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.

You're not comparing apples to apples. There's a difference.

The rule with a sizeable MH is 2 fires/day. Three fires is the exception. Loading the firebox takes 2 minutes. No kindling, no kidding, with dry hardwood. Fire starts no problem with just a lil' home made fire starter in a hot fire box. These 2 fires burn HOT (aka clean) with wide open air.

With only 2 - 3 loads/day heating your house, you are choked down on air burning slow (aka dirty).

What you like, your neighbors might not...

Aye,
Marty

Ok, I guess you could just throw a super cedar in there with a few smaller splits, that would eliminate kindling.

I wouldn't say my stove is any more dirty burning than your masonry heater. It was designed to burn clean low and slow. You have smoke at start up just like the rest of us, don't you?

I could burn money to start a fire, but I choose not to. Buying fire starter material, like super cedar or fat wood or butane for a torch, is like burning money.

Instead, I start dry hardwood splits directly, without kindling, using burnable waste material; home made fire starters - scrap cardboard with fat drippings and dry lemon rinds.

It's not a really big thing. Doing this over the years is a good way to save.

Aye,
Marty
Grandma used to say, "A penny saved is a penny earned."

 

[Jersey Bill]

On the side of my masonry heater, I gave 2 temperature gauges. One reads the core brick temp, the other reads the flue gas temperature, right before exit.
I logged the data for the last few days.
Hopefully the image comes out.
The down slope of the core temperature represents about 10,000 lbs of mass cooling off and dumping 6- 10 thousand btu's per hour into the house. Some of those down sloping lines last 24 hours.
The green line is mbh/hr in based on the delts T of the core.

 

[Renovation]

On the side of my masonry heater, I gave 2 temperature gauges. One reads the core brick temp, the other reads the flue gas temperature, right before exit.
I logged the data for the last few days.
Hopefully the image comes out.
The down slope of the core temperature represents about 10,000 lbs of mass cooling off and dumping 6- 10 thousand btu's per hour into the house. Some of those down sloping lines last 24 hours.
The green line is mbh/hr in based on the delts T of the core.

Thanks Bill, the image came out, and it's neat data. Could you explain what mbh/hr stands for, and its significance?

 

[Jersey Bill]

btu's per hour, or thousand btu's per hour is the heat output.
Usually heating devices are rated in this unit.
For instance a boiler might be rated @ 100 MBH ( thousand btu's per hour)
baseboard heat is rated at 600 btu/hr per foot.

In this case, the loss of core temperature from the core mass is the ammount of heat that the room gains.
That is shown on the down sloping core temperature line. The up sloping line is the heat gained by the core during the burn. The values arent real accurate because lots of heat is going into the room, through the glass door at the same time. So the heat into the room during the burn is understated.
Next, I will weigh the wood going in to get the thoeretical energy input to the masonry heater.

 

[Jersey Bill]

[quote author="Todd" date="1291610367"I wouldn't say my stove is any more dirty burning than your masonry heater. It was designed to burn clean low and slow. You have smoke at start up just like the rest of us, don't you?[/quote]


I dont think any stoves burn efficiently low and slow. When I first started burning my wood boiler, i was burning it with the stack temperature 400-400 deg. It seemed OK to me and thats what folks recomended. Then I got a combustion gas analyizer and tested emissions. CO (carbon monoxide) and oxygen was way high until I brought my stack temp up into the 500-525 range where I burn it now. Smoke going up the chimney is unburned fuel. When my wood boiler gets into the zone, there is no smoke.

Fuel burning devices always have maximum efficiency at full output. There the heat output will minimize fixed losses. The only way to get high efficiency at lower output is to get a smaller burner.

 

[Jersey Bill]

I wouldn't say my stove is any more dirty burning than your masonry heater. It was designed to burn clean low and slow. You have smoke at start up just like the rest of us, don't you?

I dont think any stoves burn efficiently low and slow. When I first started burning my wood boiler, i was burning it with the stack temperature 400-400 deg. It seemed OK to me and thats what folks recomended. Then I got a combustion gas analyizer and tested emissions. CO (carbon monoxide) and oxygen was way high until I brought my stack temp up into the 500-525 range where I burn it now. Smoke going up the chimney is unburned fuel. When my wood boiler gets into the zone, there is no smoke.

Fuel burning devices always have maximum efficiency at full output. There the heat output will minimize fixed losses. The only way to get high efficiency at lower output is to get a smaller burner.

 

[Dakotas Dad]

How about a matching graph of the living room temps.. as interesting as the stove data is, the Mrs wants only to know about room/house comfort. ;-)

 

[spirilis]

I rather enjoyed the thread about Dick Hill's mini masonry heater he built for one of his rooms, and I would like some day to try my hand at building a mini-me masonry heater with a proportionately small firebox. Anyone seen plans for something like that?

 

[Todd]

[quote author="Todd" date="1291610367"I wouldn't say my stove is any more dirty burning than your masonry heater. It was designed to burn clean low and slow. You have smoke at start up just like the rest of us, don't you?

I dont think any stoves burn efficiently low and slow. When I first started burning my wood boiler, i was burning it with the stack temperature 400-400 deg. It seemed OK to me and thats what folks recomended. Then I got a combustion gas analyizer and tested emissions. CO (carbon monoxide) and oxygen was way high until I brought my stack temp up into the 500-525 range where I burn it now. Smoke going up the chimney is unburned fuel. When my wood boiler gets into the zone, there is no smoke.

Fuel burning devices always have maximum efficiency at full output. There the heat output will minimize fixed losses. The only way to get high efficiency at lower output is to get a smaller burner.[/quote]

Did your wood boiler have a catalyst or EPA rated? A cat stove can burn clean low and slow if operated correctly. Nothing but steam or heat waves out of my chimney when cat is engaged and this is with low external stack temps under 300 degrees.

(broken link removed)

 

[trailmaker]

Thanks Marty S and Jersey Bill for sharing some of your MH knowledge. Some guys dream about getting a Ferrari, I dream about getting a Masonry heater. A masonry business near me works with Envirotech Radiant Fireplaces. From what I can tell they are very similar to Tempcast units. Do you guys know anything about this particular brand of Masonry heaters?
http://www.envirotechfireplaces.com/

 

[trailmaker]

Marty, I see one of you're interests as "Newfies". I've got a big brown slobbery one myself. Wonderful dogs.

 

[byQ]

Wow, this is great thread from the past. I'm the guy building a masonry heater who wondered how much less wood I would be burning as compared to a good wood stove. This thread answered the question from people who have owned both --- 25 to 33% less wood for the masonry heater.

 

[begreen]

4 yr old thread. It's interesting but not exactly a hot topic. We get lots of folks reporting 25% reduction in wood consumption going to a modern stove. Backwood's Savage noticed similar results going from a pre-EPA metal stove to a Fireview.