Also known as masonry stoves, kachelofens, Russian fireplaces, Finnish fireplaces, Swedish stoves, tile stoves, contra-flow fireplaces, radiant fireplaces, and mass-storage fireplaces.
Why Use A Masonry Heater?
Inside, masonry stoves burn hotter than metal wood stoves and their winding maze of flue (baffles) warms the surrounding masonry, which then emits heat for 18 to 24 hours. The temperature can reach 2000 degrees inside some masonry heaters (vs 700 inside a metal stove), yet they stay comfortable to the touch on the surface. At these high internal temperatures, the hydrocarbon gases ignite, leaving very minimal pollution.
How Masonry Heater Works
When burning wood, about 30% of the generated heat is supplied by the wood solids and 70% of its heat is contained in released gases. If the volatile gases are not fully combusted, they escape as wasted heat and polluting particulate emissions. Igniting and then drawing the heat out of the combustion gases turns almost every ounce of wood into energy. A slow burning, low temperature, low oxygen fire produces tar and hydrocarbons, a fast, hot, air-fed fire burns the pollutants up. Add a storage battery (the masonry) and you have a very efficient, non-polluting heating system. A metal stove gives out its heat rapidly, thus never allowing the inside combustion temperatures to achieve the 1100 degree F plus needed to ignite all the gases.
A Masonry Heater Uses Less Wood
Because the stored heat radiates slowly from the masonry, it is only necessary to light a fire once a day in most circumstances. In really cold conditions, you might need to light two fires a day. Metal wood stoves must be tended to continually and fluctuate from peak high temperatures, to no heat, when the fire is out.
If you tamp down the flue on a metal wood stove you increase the emissions of pollutants as the combustion of the wood is incomplete. A masonry heater always burns wood at the highest heat, if you desire less heat, you simply use less wood. In a well-insulated home, a masonry heater will use 1/3rd (or much) less wood, than a home heated with an old-fashioned metal woodstove. A well-designed masonry heater can easily outperform almost all EPA-rated metal wood stoves. And like a wood stove, a masonry heater can exhaust through a metal flue pipe.
The Masonry Heater: An Ancient Green Technology
The masonry stove has been around in many different forms in almost all ancient northern cultures, from the 7200-year-old Kang bed stove in China to the Hypocaust in ancient Rome. In northern Europe, 500-600 years ago, a long-lived cold spell caused local wood to become scarce and masonry heaters became common due to their efficiency.
In the past hundred years dirty coal, then oil replaced the masonry heater. Wood is a renewable resource and absorbs CO2 as it grows. Burning releases about the same amount of carbon monoxide, carbon dioxide, and methane as would occur if the wood were decomposing naturally on the forest floor.* Yet wood is a sustainable energy source, only when proper wood lot management is employed and when its energy is extracted efficiently and cleanly.
Although these effective heaters were and are still popular in Russian and northern Europe, the United States has never had a wood shortage, so the masonry heater has been pushed aside for the wood guzzling metal stove. Considering that masonry heaters are efficient and emit little pollution, the United States should take a closer look.
Masonry Heater Circulation
Directing the hot flue exhaust through a series of baffles heats up the surrounding masonry. The baffles can meander in numerous directions. Some stove’s baffles take the exhaust side to side, some up and down, some front to back, and vice versa. There is always a source of air coming in the base of the heater to feed the fire.
Yet, flues that are too long and convoluted might restrict the draft through the system, as each change of direction creates resistance to the gas flow and decreases the suction of the chimney draft.
How To Mimic A Masonry Heater
Surround your heater core with stone, brick, stucco or tile. Although kits are available, this is not a project for one new to masonry (see resources section). In the meantime, before I build one, I am simply going to pile large rocks around the wood stove.
35 Amazing Masonry Heater Inspirations
Here are some of the best masonry heater ideas out there.
Masonry heater – new stove based on an old design. A Kachelofen is a ceramic tiled wood stove which has mazelike, masonry channels within. The meandering exhaust gas warms the surrounding masonry which then slowly radiates its heat. A small windowless door allows the fire to burn very hot inside the heater. High heat and the addition of a second combustion chamber, burns up the polluting volatile gases and efficiently turns them into heat. For more examples go to biofireinc.com.
Tiled Kachelofen by biofireinc.com. Special ‘kachel’ tiles surround the internal fire brick.
Stucco And Tile
Stucco and tile masonry heater. Additional information can be found at fliesen-ofen-ritter.at.
Old fashioned masonry heater clad in stucco and tile. Fliesen+Ofenbau Ritter GmbH, have additional information on their website.
Rustic Masonry Heater
With a black trim, this masonry heater adds a touch of class to any room.
Tiled masonry heater with Asian influence. Only special ‘kachel’ tiles can touch the inner firebrick, all other tiles must be spaced away from the inner masonry, otherwise they will crack. Additional images can be found on fliesen-ofen-ritter.at.
Heater With Stucco
Stucco and tile masonry heater. biofireinc.com The small door keeps the heat inside, so high combustion temperatures are reached more easily.
Finnish Masonry Heater
Tiled masonry heater in Finland. The Finnish government encourages the use of masonry heaters with tax incentives, the program has been so successful that 90% of new homes have masonry heaters. More inspirational photographs like this can be found at contura.eu.
Swedish stove or kakelugn. The Interior has masonry baffles, the exterior is clad in curved tile. There is actually lots of masonry inside there to soak up the heat. Contura has other great examples on their website.
Brick masonry heater with heated bench in Denmark. A heater with a façade thickness of 3-4 inches, gives a moderate heat transfer, not too fast, not too slow. By Lars Helbro. Originally found at stenovne.dk
A masonry heater can be a great way to keep a cabin or mountain home heated. Not only do these heaters provide an eye-catching centerpiece, but they are efficient.
Cozy Reading Nook
Brick masonry heater in Denmark by Lars Helbro. For additional ideas visit stenovne.dk.
This masonry heater acts as a wall between two rooms in Quebec, Canada. By maconneriegillesgoyette.
Reclaimed Brick Heater
Brick masonry heater made with reclaimed brick, sand and lime mortar, lilac bluestone and a Heat-Kit heater core. By William Davenport, turtlerockheat.com. To reduce stress, masonry heaters in North America are usually built with a double-wall system; a refractory core including firebox and channels or baffles, and a separate, unattached masonry veneer. Otherwise the heat of the firebrick might crack the façade, although brick is least likely to be stressed.
Masonry Heater with wrap around heated bench, direct fire oven (on kitchen side), and wood storage by Carsten Homstead of Massachusetts. Originally found at homespunworks.com.
This masonry heater in Burlington, Vermont has a bake oven on the kitchen side. Masons: William Davenport, Spencer Blackwell, Norbert Senf. Turtle Rock Heat has more information and ideas on their website. Originally found at turtlerockheat.com
Heater With A Core
Stone masonry heater with a heatkit core. If there is too much façade mass, 5″ or more, the mass can slow down the heat exchange. An efficient heater should produce heat at the same rate as the heat is given off (emitted). The firebox size should also match the size of the heater and home.
It is not efficient to put your heater on an exterior wall. When on an exterior wall, that portion of the masonry facing toward the outside, will simply be heating the outside air. This heater is an interior wall. Vermont masonry heater by smithandvansant.
Heater From Canada
A masonry heater’s chimney can be ceramic or metal. Large fireboxes reduce combustion efficiency and generate higher emissions. Keeping the window small means the heat gets absorbed into the masonry. Canadian heater by bien-o-chaud-portail-poeles-et-foyers. Originally found at bien-o-chaud-portail-poeles-et-foyers.com
Soapstone tiles give a modernized style to this masonry heater.
Brick masonry heater. There is no reason why some heaters can’t be low and long. There is a wood fired cookstove on the opposite side of this heater. More images can be found at stenovne.dk. Originally found at stenovne.dk
Local slate covers this masonry heater in Vermont by William Davenport. The heater has doors on both sides. Turtle Rock Heat has more information on their website. Originally found at turtlerockheat.com
Heater With Concrete
Masonry heater that extends to room on other side of wall. Custom concrete slabs, steel, black walnut wood box top, bluestone, lilac bluestone. Originally found at turtlerockheat.com/charlotte.html
Soapstone masonry heaters come in all sorts of shapes and sizes. Soapstone has thermal properties that exceed all other stone, brick or stucco. These Tulikivi heaters are at the virginiaradiant showroom. Pictures of a Tulikivi being put together: mha-net.org
Heater With A Window
Masonry heater with large see-through windows. A large firebox reduces combustion efficiency and generates higher emissions. See-through heaters also increase the amount of heat escaping the firebox and therefore lowers combustion temperature and generates higher emissions. Visit brunner.de for additional information.
Masonry heater in a bathroom by peacedesign. If the distance from the core to the surface of the stove is very thick (5″ or more) or complicated (many layers), the heat will radiate out very slowly. An efficient heater should produce heat at the same rate, as the heat is given off (emitted). A massive heater will also be much slower at responding to changes in temperature.
Stucco and mosaic masonry heater. Core is by Heat-kit. More information is available at mha-net.org.
Heater In New York
Grey colored tiles have a clean appearance, making them great for a modern style.
Wood stove on the bottom, Kachelofen tile on top. This stove will give you fast, direct heat passing through the metal, and the slower, radiant heat from the upper masonry baffles, whose surface has been tiled. Yet because the metal gives off heat so rapidly, this stove may not reach the internal temperatures necessary to burn off all hydrocarbons. Other wooden stoves can be found at ofenhaus-hoppe.de. Originally found at ofenhaus-hoppe.de/kachel%C3%B6fen.html
Masonry Heater For A Two-Story Home
In a two story home, this is one of the best locations for a masonry heater. A complete gallery of this heater is available on erdwerk-keramik.at.
Masonry Heater in the Via Miodula Hotel, Poland. You can find more images at villamiodula.pl.
Masonry stove in France by poele-cuisiniere.fr. Remember if there are no flames, half the wood is being wasted as smoke…
Heater With Earth-Clay Plaster
This masonry heater is veneered with the same earth-clay plaster used on the walls of the main floor. A heated bench topped with sandstone makes for a warm perch on winter days. By Gimme Shelter Construction. More photographs and descriptions can be located on gimmeshelteronline.com.
Paving Slab Heater
How A Contra Flow Heater Works
Scheme of a Contra Flow Heater
As the fire burns, air is drawn in through the primary air intake (b), passes up through the grate in the firebox floor (c) and feeds the burning wood. Due to the design of the fire box and its angled ceiling, heat radiating from the fire is reflected off the firebox walls back onto the fire, helping obtain firebox temperatures of 600 Degrees C. a prerequisite for secondary ignition.
Air from the secondary air intake (d) located in the loading doors, the flame and unburnt gases rush up through the narrow throat in the firebox ceiling (e) and enter the secondary combustion chamber (f). Due to the angled ceiling, the flame, air and gases are pressurized slightly.
Once through the throat they expand, tumble and mix, allowing secondary combustion and temperatures in the region of 900 degrees C ( 2,200 degrees F). The hot gases pass over the top of the side walls of the secondary combustion chamber into the vertical flues on both sides of the heater.(g) Drawn by the draft from the chimney, the hot air flows down the flues transferring its heat to the flue walls before entering the chimney at the base of the heater (g). Via: pyromasse.ca
Note the drawings on right, the channels (baffles) can meander up and down, side to side or both.
Masonry Heater Build Guides
Masonry Heater Resources
Masonry Heaters: Doors
Certified Heater Masons
Modulars/Freestanding Masonry Heaters
Vintage Masonry Heaters
Gorgeous antique tiled stoves: vintageelements.com
Pellet Masonry Heaters
Pellet burning in a masonry wood heater. heatkit.com