Cooking or heating with wood makes you independent and self-sufficient. It is an energy source that you can manage from A to Z yourself. With simple means you can build a storable stock. The Norwegian Directorate for Civil Protection and Emergency Planning requires that all houses from a certain size must have an alternative heat source, in practice a wood-burning stove. The man & the wood, from the Norwegian Lars Mytting describes the wonderful feeling and bond of users with firewood.

In 1742 Benjamin Franklin (known of the lightning rod) designed for safety a metal stove. That was a big improvement over the regular stove used until then. His friend Robert Grace produced them. Franklin would not patent it. He wanted the technology to be freely available. This is sometimes referred to as the first example of the "open - source principle”.

Leuvense stoofA with (soap) stone coated stove stores more heat than a (cast) iron one. By radiating heat then slowly the room stays warm longer. Depending on the insulation of the house this is an important consideration when buying a heater .
Even if you do not have a (soap)stone heater you can store heat in stone. You can construct a double cage mesh (concrete nets , rebar) around and against (a part of) the stove, and fill it with (decorative) dry boulders. In garden centers you will find beautiful gabions (and stones) for this. Warm air can circulate between the stone in to the room. The heated stones hold the heat longer than the iron stove.

Stove pipes also give a lot of heat. It is therefore not necessary to hide them indoor behind bricks.
In Chinese Zhejiang King saw the kang: a low stove of which the heat of the flat horizontal chimney was used. It were 2m2 large, low, flat benches during the day on which overnight sleep mattress were laid. Due to wear and leaks these constructions of clay, straw and loam had to be remade every 3 to 4 years again. The old were pulverized (contained many minerals) for the compost heap.

There are also beautiful stoves with next to the combustion room an oven, and sometimes even a boiler (hot water tank). The hob has with rings reducible openings to set appropriate pans, kettles and waffle irons. There still may also be a fume hood built on top. Our mother baked cake in the 'Louvain stove" on a metal band ring, with two handles, and filled with baked clay, heated along two sides on the stove. The accumulated heat was enough to put them in the oven, and so to bake the cakes.

Centuries ago there were already houses with heating: a fireplace and air ducts under (2 rooms of) a house. The feeder on one (outside) side, the chimney on the other side. In Spain the system is still known as the 'gloria', in Korea as 'ondol' and in America as a 'crimean oven'. (hospital tent with a flue covered with metal plates across it).

Wood stove, coal stove burner

Can you burn coal in a wood stove? Or vice versa.

A coal fire is usually much hotter than a wood fire. And can be to hot for a wood stove. Burning wood in a coal stove is safe. Conversely not. Iron grates, the hob or parts maywarp.

A coal stove is made ​​of cast iron, a wood stove may be of steel (and /or stone).
A coal fire usually has only a small fill opening, for logs you need a greater (door).
Coal you fire on a heavy, cast iron grate with wider grooves, wood can on a lighter grill, and with narrower slots .
To stoke coal the walls also better are of cast iron or covered with cast iron plates, or there is a heavy cast iron basket or coal bunker in the stove.

A coal stove can easily burn all night with little air flow. In the morning you open the air grid, sometime later rake up and refill it and you can go on for hours.
A wood stove usually can also, but less and with less heat , continue to burn with BKB (brown coal briquettes). They are allowed, but no coal. All panels could finally warp and crack.

A burner usually has a switch to divert to another (shake) grid with corresponding air flow. The term does not mean you can (or should ) insert everything to burn, but you can choose between wood or coal.

1,000 kg of good quality coal would give after incineration approximately 30 to 50 kg of ash. Between 0.43 and 1.82 % of the burned wood mass remains as ash (means 4.3 to 18.2 kg on 1.000 kg wood). The composition depends on the type of wood, soil, evaporated and air discharged materials, combustion temperature and chemical processes. 25 to 45% may be calcium carbonate, less than 1% phosphate and less than 10% of potash.

You put boilers, hot pots or pans on the stove without burning them or continue to cook if you have one metal pad (table protector) under it . Or possibly two together. Failing that, you can also take 2 steel slats. And possibly two cross about that. Keep (the tower) stable. Clay tiles are also handy for this.

Make sure you have(barbecue) forceps at hand to manipulate the hot rod mats or strips!

Makeshift stove-oven
kachel1A large (copper, stainless steel ... ) bowl upside down on the stove or heater turns the space underneath into an oven. You can bake pizza, cake ... in it. Be careful that everything is stable, the ears of the pan not rest on the heater plate, and have thick oven mitts at hand.
Or just use one straight up with a properly fitting lit.

Very important when using a (coal, wood etc.) stove , is a good regularly swept chimney, and adequate ventilation. ( See also CO poisoning.)

Firewood must dry about a year before you use it. Prunings (including roses, lavender, etc. ) is good kindling. Cut them to size and let it dry in a crate.

If your fire is build good (see <Making fire>) you can start the stove with 1 match. Of course the air and the smoke exhaust are all the way open.
(News) paper is used to light the stove. But don’t just put some sheets together. Which exclude all air circulation, making the flames underneath suffocate. Crumple the newspaper first. And even better, tear them into pieces, so that the air can pass through them.

A single log does not burn, it will extinct. You need to have 2 or more blocks together. Heavy and hard wood burns longer than light and small wood. Do not try to keep the fire all night with little ventilation and smoke extraction, you increase the risk of CO poisoning. Let it rather burn harder and light the stove again in the morning.

That risk also exists if you fill the stove too full (+ 60%). Then there is too little air near the fire. When 'smothering' (burning with little air) you get too slow, 'cold' and incomplete combustion with a lot of fine dust, risk of chimney fire and CO poisoning. Stove glass, wall and chimney get a good layer of heat-retaining soot: 3 mm of soot causes a heat loss of 10%. Cleaning the inside of the stove can produce up to 30% heat gain!

In addition, you waste the most energy: flue gases are not burned but discharged through the chimney.

It is better to burn considerably so that the energy is stored in the (preferably well insulated) house as heat.

Safer is to prepare a start package with small wood, for example wrapped in newsprint. In the morning you can effortlessly and quickly light the stove again. If there is glow in it, the package will anyway ignite again after some pokers.

If there is no fire in the stove, but still hot fuel it can ignite again by increasing the air supply. If that fails, you can try to put a wad of newspaper in the ash box and fire it. Then you do not have to open the stove and so avoid smoke. If that fails, you can throw a burning wad, possibly with some small wood sticks wrapped in it, in the stove.

Do not wait with refilling until there are only some glowing coals, but do so while the flame is still burning well. Ideally if your fireplace is still full of wood for a third.

If you don’t have a dog or pig to eat bones, you can throw those of poultry and rabbit in the stove. Ash you can (after wetting them in soft rain to prevent dusting) sift and do on the compost heap. The bigger charcoal lumps can go back into the stove.

In my childhood, everyone scattered his ashes in the winter on the street, so there was always a narrow passable path. Everyone did that in front of his door up to the next spreader (or to the end of stock). It was no obligation, no law, no municipal sprinkle service, but simply: solidarity and neighbors care for each other. Such spontaneous social behavior would undoubtedly result in summons today.

Ash from the stove contains everything that trees need. So you can scatter it fine in the woods on the snow.

Rocket stove
Making an intense fire with very little wood and with little smoke is possible in the Rocket stove. Place four bricks in square shape with a hole in the center, 3 to 4 layers high. Take one basic stone away so you get a fire opening. Ready. It's even better if you isolate this heating turret.
Insulating firebricks can be made by mixing clay with a lot of sawdust. That will largely burn away afterwards, but there remain insulating cells in the (much lighter) stones.

You can also make the oven with a metal tube (cans). Put a wider tube around and isolate the intermediate space. The gap between the pan and the outer edge of the stove better is quite small: 15mm (to let little heatescape unused). If you can put a ring (tube) around the cooking pot, the chimney will also heat the side of the pan. In the summer this is a useful outdoor stove.

CO is a toxic, flammable gas produced by incomplete combustion.
CO2 (also exhaled by us) is not flammable and is even used as an extinguishing agent.
Wood consists of 49% carbon, 6% hydrogen and 45% oxygen and nitrogen.
Peat of 52% carbon, 6% of hydrogen and 41% oxygen and nitrogen.
Anthracite to coal 66-94% of carbon, from 5 to 2% hydrogen and from 28 to 3% of nitrogen and oxygen.
The combustion products are carbon dioxide (CO2 ) and water.
If there is not enough air supplied, carbon particles remain unburned as soot.
Unburned substances such as mineral salts, remain as ashes.
Fire consumes a lot of oxygen: a closed stove needs 35 to 50 cubic meter of air per hour, a fireplace to 250 cubic meters. ( A room of 7 x 4 m, 2.5 m high makes 70m3). So at least take always care for good ventilation!

The power is the amount of fuel (energy), which is needed to heat the space in which the heater is. This parameter is expressed in kW and indicates which stove is suitable for the volume (m³) that you want to heat. With too little power a space is insufficiently heated. With too much capacity, it will become too hot and there is a tendency to lower the stove which results in incomplete combustion and soot deposit on the glass and in the combustion chamber.

Combustion efficiency of heaters
A fireplace with an efficiency of 80% uses 80% of the energy of the wood to heat the house. Efficiency decreases as the fire burns more slowly so the flame is less complete.

Heat loss is caused by:

Incompletely burnt particles which remain in the ash.
Incompletely burned particles that disappear via the chimney with the flue gases.
Waste heat from the flue gases rising through the chimney.

A fireplace has an average combustion efficiency of 10 to 15% , a classic wood stove got 45%. Modern build in fireplaces for wood get 60-65%, and a modern wood burning stove, similar to a classical central heating on gas, a yield of 75%. So 3 logs into your stove give as much heat as 12 blocks in a fireplace.
Modern coal and gas stoves get 80 and 85%, and a top of (80 to) 90% for gas condensing boilers and heat accumulating soapstone or tile wood stoves is achievable.
They lose on average 8.5% yield of residual heat in the chimney. This hardly can be lower, because otherwise the flue gas velocity will be too low and smoke impact can occur. Incompletely burned particles have an average of 0.75% heat lost through the flue gases and about 0.75% in the ashes.

Flamme Verte - 'Green Flash'
For wood-fired heaters there is in France a quality indication such as for hotels with stars. The best devices can now have 7 *. «Flamme Verte" takes into account energy efficiency (greater than or equal to 70%), carbon monoxide emissions at or below 0.3%, and emissions of particulate matter. Through these, energy and environmental efficiency increased since 2010 from 40 to 80% (even 90% for pellets), CO decreased from 1 to 0.06%, fine particles of 500 mg / Nm3 at 13% O2 to 90 mg / Nm3 at 13% O2.

Old stoves gave 40 to 50 grams of emissions per kilogram of burned wood. A good new stove less than 5 grams. The best only 1.25 grams of fine dust, with a utilization of 92% of the energy from the firewood!

In contrast, old stoves emit an average of about 800 milligrams of particulates per normal cubic meter (mg / Nm³). The latest devices may emit a maximum of 40 mg / Nm³. Especially mass heaters (soapstone stove, etc.) score very well here. At the other extreme, hearths achieve particulate matter values of 3,000 to 5,000 mg / Nm³.


Flue gases burn from 350C with a lot of air supply. They escape from the wood at 100-150C, but without burning. Sin of the energy waste. You can limit this by burning 'upside down' (top-down fire).

With the classic construction, the largest blocks at the top heat too slowly. They smoke before they ignite. You have lost that energy, and you produce a lot more fine dust.

Good combustion is a clean combustion. The finer your wood, the better the combustion.

Black glass windows are a result of poor heating.

Black stove windows can be cleaned with a wet wad of newsprint and some ashes.

A topfire would burn healthier. It burns from top to bottom. You pile logs close together and make a small fire on them. The advantage would be that the combustion chamber temperature rises more quickly, the gases burn better and the timber has a longer burn time.
Solid fuel is not burning (directly), the material gasses first by the heat, after which the gas burns. With an underlying fire many gases from the upper fuel are driven to condense unburned into the chimney as creosote. A topfire would burn those gases in the upper fire. That would create less creosote, improved combustion, and thus deliver more heat with less fuel. And safer fire and less smoke and pollution. Creosote burns as fiercely as coal. It should thus better burn in the boiler room and deliver useful heat, instead of losing polluting energy.
My boiler room is too small to apply and test this, but the explanation sounds plausible.
I knew someone who fired his boiler with sawdust. He placed four tubes in the corners of the refrigerator-sized chamber, filled everything with firmly pressed sawdust, and then removed the tubes to get enough air in the fuel. The sawdust was allowed to burn out from top to bottom. That lasted about 24 hours.

Eco - fan (Ecofan): hot air without electric consumption
The EcoFan is a fan which helps distribute in the room heat from a heater. A wood stove gives especially nearby radiant heat. The cold air that is sucked in can feel like an unpleasant cold air flow to the heater. The warm air rises on the heater and warms the ceiling above. A fan breaks through this natural flow and blows a large part of the warm air into the room.
EcoFan is based on a thermoelectric element and therefore consumes no batteries or AC power.

Seebeck discovered in 1821 the direct conversion of a temperature difference into an electric current at the interface between two different metals or semi-conductors.
The French watchmaker Jean Peltier discovered the reverse effect in 1834: the conversion of an electric current to a temperature difference.
The two are actually the same processes that run in the opposite direction. They are referred to as the Peltier -Seebeck effect or thermoelectric effect.

Perfecting and mass production of on this principle based cooling element got a strong growth as a coolant for the processors of most personal computers.

A EcoFan also uses this principle. The (aluminum) base of the fan is on the hot stove, and transports the heat to the Peltier element in the middle of the fan. The top of the thermoelectric element is separate from the heat source and is equipped with a heatsink. The temperature difference between top and bottom is converted into electric power which drives a small DC motor that lets rotate the fan blades. The fan sucks air through the cooling fins thus maintaining the temperature difference.

If the stove reaches a temperature of 65 degrees, the fan starts spontaneously, and up to 300 degrees rotates faster and faster. The airflow varies by model between 3 and 5 cubic meters of air per minute. Through better heat dissipation it is thus possible to use 14% to 19% less wood to get the same heat without extra energy consumption.

Vulcan Sterling fan

Full mechanical heater fan that will not get overheated. The hotter the fire the harder it runs.

This fan starts usually not easily but needs a push to trigger the piston.

It is a Stirling engine driven fan that quietly and efficiently blows warm air above the heater through the room and so dramatically increases the effectiveness of the heating appliance.

The Stirling engine is energized by the rapid heating and cooling of the same volume of air in the piston. Warm air expands and pushes the piston upwards; if the same amount of air is rapidly cooled, it contracts and the piston will pull downwards. This action rotates the fan blade. (Expensive, but beautiful.)

How to avoid smoke in your room

Make sure the stove burns with an open flame before filling it. (read <Chimney> ) :
Never cover the whole fire with new fuel, leave at least one side free with a burning flame and fuel.
Thus released CO gas can burn gradually. Otherwise it accumulates in the stove, and can - if a flame is released - flop.
The better the combustion, the less CO is produced.
So a minute or 2 before loading, open the air intake and exhaust, and leave open even a while after filling. Don’t open the door with a jerk, first a little, and then slowly more (with any other air supply closed so that no "false pull ' occurs).

Damp wood must dry in the heater (energy waste). Those resultant fumes can explode.
Other cause of inadequate draft: chimney too short, too long, too small, too many curves, not swept(in time), too cold (not isolated).
A fan or extractor hood sucks too much air out and causes underpressure. This can lead to kickback and smoke in the chamber.

Our ‘Leuvense stove’ formerly stood on bluish glass feet, a kind of dishes. That had a practical reason: when cleaning the iron stove legs were not wet, and so there were no rust spots on the floor. I still lay stone or ceramics (e.g. a small, round mosaic tile for bathroom) under the stove legs.

Car on wood (gas)

In the absence of petrol, many cars were converted during World War II. Wood is heated to 700-800 ° C without oxygen, resulting in wood gas. Water, tar and other solid components are filtered out. This flue gas is mixed with air through a valve instead of carburetor and is burned in the engine. Adjustments to the engine are not necessary for this, but the power does decrease by approx about 20%. 100 kilograms of wood provide the same amount of energy as 36.5 liters of petrol.

If it’s freezing cold, go stand in the corner. Which is 90 degrees.