When I was building my house, I decided to install a northern European style masonry heater that differs from a typical wood stove in several ways:
a.) You load the fire box and burn it hot. Because the fire gets all the air
it needs the combustion is very efficient with little smoke or creosote in the
exhaust gases. Instead of going right up the chimney, the hot combustion gases
follow a serpentine path and transfer heat to the walls of the masonry path
they go through. Therefore, the fire lasts about an hour, but the heat soaked
into the masonry mass radiates out for a day or more. It is a very even heat.
We burn twice a day when it really gets cold.
b.) Except for the metal and glass door, a masonry heater does not get dangerously hot. In fact, you can lean against it and get warm quickly. It is the next best thing to a hot shower.
|My indentured servent...I mean my son, who--along with my other kids--enthusiastically offers to bring in the wood (ha ha).||This is a typical load. It might have more layers or fewer, depending on the size of the wood. We usually burn this much twice a day when it's cold.|
After 10 years of depending on the masonry stove for all of my winter heat without any problems, I cannot imagine returning to the noisy, unreliable furnaces that I used to have to deal with. However, the disadvantages are not lost on me.
a.) It takes up more space than a typical metal stove (“architectural feature” is the way the Toronto company I got the core from put it).
b.) There is an up front investment of thousands of dollars just for the core. That does not include the foundation (the heater is very heavy), chimney--and skilled labor if you hire someone to install it. This is not one of those ready-made soapstone stoves that you set anywhere. The core must be faced with a masonry material. I used river stone, and it was a lot of work. I do not have any backup heat, but most people would, and that would be an additional expense.
c.) The wood needs to be split and seasoned (dried out). This means keeping it out of the rain, too. Actually, any kind of wood stove should get dry wood. Masonry heaters work best if you select wood that's all roughly the same thickness. If you have a lot of skinny wood and one thick piece with knots, it's inefficient. The big piece that take's longer to burn will keep you from closing the chimney top (see f)) in a timely manner. About half way through the burn you should use a long poker to drag any wood that's not burning fast to the front where the air intake is. This evens out the burn.
d.) This also applies to all wood stoves. Chimneys that go up an outside wall--exposed to the outside cold air, in other words--are a bad idea. In particular regarding masonry stoves, the envelope of cold air they harbor makes starting a new fire difficult because it doesn't draw properly until the cold air is replaced with hot air. Having a chimney inside the house gives you a warm air envelope in the chimney ready to start drawing right away. The inside chimney adds to the efficiency and acts as a heat sink. Because the chimney is warmer, creosote from the exhaust gases are not as prone to condensing in the chimney. I have not had to clean the chimney in 10 years of use.
e). It helps if your floor plan on the level that you have the heater is open, to distribute the heat.
f). This shocked me and shocks everyone when they first hear it, but I'm completely comfortable with it now. The kit came with a door for the TOP of the chimney. A long wire goes down through the chimney, out a tiny hole. You open the door with the wire just before you build a fire. Then you close the door after the fire has burned down to charcoal but before the charcoal has burned out. I had a carbon monoxide alarm and fretted about it at first, but no more. This is not a coal stove and it does not seem to generate significant amounts of CO
g). My unit has an "air wash" glass door, which means the intake air to combust the wood rushes in from slots just above and just below the door. This keeps most of the smoke away from the glass, so we don't have to clean the glass door very often. However, the upper bake oven door does not have this feature and so blackens after a couple of burns. That said, I still like the bake oven. It's a bit messy but not hard to clean.
I bought a stainless steel coil and installed it in the heater to heat some of the domestic hot water (showers, laundry, dishwashing) for my family. To be practical, however, you really need a tank above (mine is on the second floor) so it can thermo siphon through continuously.
|My friend Greg Kohler calls this "The Fire Channel." We never get tired of it. Fire roars through the bake oven on top (really cool). After the wood has burned to coals, you can bake in the oven. The hot combustion gases first go up, then all the way back down along the sides through heat exchanger channels and finally up the chimney (in back)..||Here is a scratched picture from about 1998 when I was just finishing the stove, except for the doors. I was also making my own kitchen cabinets and drawers (seen scattered around). Both can be done as a do-it-yourself project, but neither is what you would call a "weekend project."|
When we moved from the city to our house in the country, I wanted something that would attract the whole family to one place, rather than be scattered throughout the house.The masonry stove does that. It replaced the TV, which we left in the city. Did I mention that it's great for drying clothes on, too?
If you can travel to my house (in Williamsport, Pennsylvania up Bottle Run Road, 3 miles west of Lycoming Creek Road/ Route 15) I can show you my masonry heater. I'm happy to answer questions and go into details, either by phone or e-mail. Contact me. It's not unusual for me to spend 20 minutes on the phone--which I'm happy to do--but I do not have free calling. So you call me back if I'm not there--don't expect me to return long-distance calls. Around 8:30 PM EST is usually good time. 570-321-7468
There are at least two ways to go about buying a masonry heater. I bought the core from a company in Toronto, Canada, and did all the rest of the work myself. Some people hire local masons then to build the foundation, chimney and facing, Tapcon the doors, in, etc.. There are now enough masons in North America to build the heaters from scratch, on location with fire brick. I hear it takes about 3 days.
I have been reluctant to specify where I bought the core of my stove, but everybody asks, so here it is--good and bad. The company was TempCast. The reason I settled on Tempcast is because I wanted to do as much of the work as possible, yet I didn't feel confident to build one completely from scratch. At the time--over a decade ago--they were the only ones selling such a kit--large blocks that were keyed to fit together.. It's likely the landscape has changed, so look around.
With the perspective of time, I am happy with the TempCast product, but there were some times I wondered if I had made a mistake. When the core arrived, one of the giant 80 lb. blocks had broken in two. I documented it with the shipping person. I assumed it would be replaced, but John, who was running TC at the time, told me to just glue it together with refractory cement. I insisted on a replacement, but was forced to pay shipping of this 80 lb block from Canada. Then, when I assembled the stove, one block was misshapen. There was a huge gap and it rocked. Again John told me to just fill it with refractory cement. It was a clear manufacturing defect and he knew about it. I did fill it and it seems to be ok, but that and other things like it after I had paid my money left a bad taste. Still, it has worked out well. Saves me over a thousand dollars a year in heat and I love it. Just look around and talk to lots of people before you plunk down your money.
When I faced the core with rock, I first wrapped it with expanded steel lath to prevent cracking, and this worked. But I talked to another guy who faced with brick--no expanded metal behind--and crack opened up.
I ended up removing the rock wool from the top.
After a couple of years the wire to the upper chimney damper frays and breaks where it goes through the chimney wall. Better to leave it long, detach and move it a foot or so every couple of years before it breaks--it's a huge hassle to thread it through again.
More Information/ Links
Below are some good links about masonry heaters. And you can find other links there about cool related subjects like old fashioned, wood fired bake ovens. Lots of gorgeous photographs to drool over, too.
This Masonry Heater Association (MHA)"Virtual Mall" is a good place to start. http://mha-net.org/html/mall.htm
http://mha-net.org/index.htm This is the home page of the MHA. I really enjoyed reading about some of the member's work in a village in Guatemala with cook stoves. Here too http://mha-net.org/docs/v8n2/docs/mom-2005report.htm
If you are a do-it-yourselfer, these people are selling plans http://www.singingfalls.com/masonry_furnace.html Note that I have not actually viewed this CD. Check out their home page, too. They are shepherds, hand-spinners and weavers of mohair http://www.singingfalls.com/index.html
This page is just sort of fun to see how they make a masonry bake oven--something I've always wanted to do. http://mha-net.org/html/projects.htm
Please share your experiences with masonry stoves so I can pass it on to others.
What Mark Twain had to say about masonry heaters http://www.timelyconstruction.com/?page_id=71
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