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Finnish Masonry Stoves | |
Finnish stoves burn wood extremely efficiently, equal to about 85% usage of BTUs in the combustion process. Conventional wood stoves, by contrast, have an efficiency rating of about 45% to 60%. Finnish stoves use approximately 3 to 4 cords of wood per heating season. Conventional woodstoves typically use more than 6 cords of wood, and lots of heat is lost up the chimney. Also, the burn is not nearly as clean as a Finnish stove. |
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In a masonry stove, approximately 30 to 40 pounds of wood is burned in a flash burn until it is out. The
fire transfers its heat to the brick mass, and the bricks radiate heat evenly throughout the day. This one fire can heat a well-insulated house of 2,000 square feet from 12 to 24 hours. You can fire the stove twice a day if the weather is colder. The burn time for hardwood is about 40 minutes, softwoods
less. You may burn softwoods in these stoves because they burn so hot and efficiently that the gasses
that normally don't combust and collect in your chimney as creosote are burned completely.
 There is no need to babysit these stoves. The surface temperature of the stove never exceeds 160
degrees Fahrenheit. In fact, these stoves like to be hugged! The chimney is separated from the
mass of the heater by a horizontal flue, which is part of the design and takes the form of a
warming bench. (Try to keep your cats off this.) Benches can be long enough to lie down on and
between 18-24" wide. In addition to providing excellent heat, the stoves can be built with an oven
chamber for cooking pizzas turkey, pies, breads, and so on.
These masonry heaters provide functional warmth that is good looking. You wouldn't put your furnace in your living room, but a Finnish stove made out of brick, stone, or tile is a thing of beauty.
The construction of these heaters requires a dedicated and highly skilled mason who knows the
intricate internal design and has special knowledge of the materials. Since these stoves go from room
temperature to 1,600 degrees inside the fire box, the mason must be aware of how the mass will
expand and contract with these temperature swings and plan for it so the stove will not heave itself apart.
My masons and I will travel almost anywhere to build a Finnish stove.
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