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Things worth knowing

Things worth knowing

Nice-to-know information gathered in one place

Irrespective of whether you are a new or seasoned user of wood-burning stoves, there are lots of things that can be nice to know both before and after your purchase. We have gathered all this information in one place so that it is quick and easy for you to immerse yourself in the topics you find interesting. Click your way through the topics underneath.

TermaTech’s stoves are convection stoves. Their basic structure is produced in 3-5 mm thick quality steel. Cast-iron components are always used in TermaTech stoves where the temperature is highest. Examples of this are the bottom of the combustion chamber, the internal frame of the door and other parts.

The most important thing is that the stove is built to last for many years and you are assured of this when you choose a TermaTech wood-burning stove.

Stove type – emission of heat

Roughly speaking, there are main three types of stove: Radiation stoves, convection stoves and storage heating stoves.

The drawback with radiation stoves is that the surface of the stove gets very hot and the area immediately surrounding it gets hot rapidly. Very few of the stoves produced today are radiation stoves.

Convection stoves, which are the most common type of stove on the market today, have an external jacket, which is open at the top and at the bottom. The air between the actual stove and the outer jacket is heated up and the warm air is sent out of the stove and the air circulated around the room. The air is distributed better than it is with radiation stoves.

Storage heating stoves accumulate the heat from the wood-burning stove in order to emit the heat over a longer period later on.

Warmed air is blown down the inside of the glass and counteracts and minimises the formation of soot on the glass. All TermaTech stoves are equipped with an air wash system.


Generally speaking, wood-burning stoves do not require much cleaning. However, you must check all sealing bands and moving parts before the start of the heating season and rinse and clean the inside of the stove once the heating season is over. The ash is emptied as required, but be careful – if there are smouldering embers in the ash there is a risk of smoke or fire damage in your waste receptacle etc.

The glass is cleaned either with TermaTech’s special glass cleaner of with a little bit of water on a piece of kitchen roll which is then dipped in the ash and used to scrub the inside of the glass.

The surface of the stove is cleaned using a dry cloth, a soft, dry brush or a tightly scrunched up moist cloth. Never use water or cleaning agents on the painted surfaces.

Top or rear outlet

The rear outlet solution requires a good passage of air from the chimney since this solution creates more resistance to the path of the smoke. The smoke should preferably follow its natural trajectory – upwards.


Soapstone is a natural product which has an outstanding ability to retain heat. This stone is often used for storage heating stoves where a more even distribution of heat is desired. Every single soapstone has millions of years of history behind it and has a unique appearance and structure.

Chimney draught

Even the very best wood-burning stove cannot function properly if it isn’t connected to a good chimney. The chimney is “motor” or “lungs” of the stove, if you like. A poorly insulated chimney or chimney that is too low will often result in a bad draught.

A bad draught results in poor combustion and smoke spillage when the door is opened.


An insulation material that affects the temperature in the combustion chamber and, consequently, results in a higher temperature and cleaner combustion.

External combustion air ducts

A connection whereby the air required in order for the stove to function correctly is supplied externally. An external air supply to the stove’s combustion air duct is often necessary in new houses because the houses are extremely airtight. In airtight houses, a vacuum can easily be created which means that the wood-burning stove is not able to function correctly.

When the new wood-burning stove or chimney is to be installed, there are not only requirements for chimney heights, test certificates, executive orders, fresh air supply, etc., but also for the installation itself.

It certainly does matter who drills a hole in your roof or your wall, and we therefore recommend that you ally yourself with a professional you trust. Here on our website you can find reference to our dealers.

If you want to do the work yourself, read the installation instructions for your specific wood-burning stove carefully before throwing yourself into the work.
Below, we highlight what is particularly important in connection with the installation of a wood-burning stove.

Smoke extraction
You can choose whether you want to install the flue pipe on top of the stove, or whether you want the smoke outlet at the back. Be aware, however, that it requires a good draft from the chimney if you choose the rear exit solution, because this solution provides more resistance when the smoke is to go out, as the smoke will preferably go the natural way, which is upwards.

It is important that the connection between the stove and the chimney is tight. If there are many and sharp bends, it creates more resistance and turbulence. This can create draft problems with “smoke in the living room” as a result. Brick wall chimney
If you have an existing brick wall chimney, it must at least be equipped with an internal lining. An old-fashioned brick chimney can, as a general rule, not ensure the necessary draft. The easiest way to renovate an old chimney is with a steel lining, because the steel lining gets hot quickly and can create the right draft, while avoiding condensation problems. Besides, it is easy, fast and cheap to install.

Steel chimney
The steel chimney is created to meet the current requirements and rules for modern wood-burning stoves and is perfectly suited to the Danish weather. It creates the necessary feature. For new, tight houses, we have developed a unique system that seals between the chimney and the dam barrier, so that the requirements for tightness are met.

The height of the chimney
The height of the chimney must live up to the national legislation in force at any given time (Building Regulations or Executive Order). Whatever rules may apply when installing the chimney, it should be of such a height that it directs the smoke away without disturbing the surroundings and that the draft conditions for the combustion are in order.

Once the stove is installed
Once the new wood stove is installed, the installation must be inspected by the local chimney sweep. The chimney sweep checks that distances to combustible materials are complied with and that the installation meets the usual requirements.
NOTE: The chimney sweep does not check that a vapor barrier or underroof penetration has been installed – you must agree this with your fitter.

Under each of our stove models, you can find specifications and download a user guide so you can see what you need to be aware of, rules for the specific stove model, and how the stove should be installed.

The firing-up stage is absolutely crucial to getting a well-functioning wood-burning stove since proper firing-up quickly creates an optimal combustion temperature and a good chimney draught.

How to fire up properly

1: Place 2 large pieces of fuel (5-8 cm thick), with the bark facing downwards, at the bottom of the combustion chamber.

2: On top, build a little tower of 12-14 kindling sticks with an adequate supply of air between them.

3: Place a couple of briquettes/pellet bags between the uppermost layers.

4: Ignite the briquettes/pellet bags so that the wood burns from the top down. Leave the door slightly ajar.

5: After approximately 10 minutes, or when you can easily feel the heat at a distance of 15-20 cm from the glass, close the stove door.

6: Once the flames have died down to embers, it is time to add new wood. NEVER OPEN THE DOOR while there is flames! If there are flames, there are gases – if there are gases, there is smoke – and if there is smoke, it will come out when the door is opened!

Carefully, open the stove door 1-2 cm, and after approximately 5 seconds it can be opened fully.  You can now put 2-3 pieces of dry wood on the stove – it may help to stoke up the embers before you put the new wood on top of them.

Always remember:

– Light the fire at the top, that way you can save up to 80% of the particle emissions being emitted into the environment during the firing-up phase.

– Always use one or more firing-up blocks and lots of dry firewood that has been broken up into small pieces.

Basic rules for correct firing

1: Use wood that is clean and dry with a maximum of 18-20% moisture. A moisture meter is relatively inexpensive and can specify the water content. See TermaTech’s moisture meter at your dealer ‘s showroom.

Wet wood does not burn well, gives off a lot of smoke and creates more pollution. Never fire up with waste materials – waste materials may contain carcinogenic dioxins and will render the warranty void.  Never fire up with carbon or carbon products.

Never fire up with pressure-impregnated wood– even small amounts contain acids that will destroy the stove and chimney.

2: Make sure there is an abundant supply of air – An insufficient air supply can result in the smoke containing harmful particles. It can result in the formation of soot on the window, in the stove’s interior and in the chimney. It also harms the environment.

3: Fire up a little at a time – The fire has to take hold in the fuel so that the temperature gets high quickly. Large pieces of wood have a lot of mass and a small surface, which means that it takes too long to get the core temperature up. Consequently, the fuel will simply smoulder instead of burning.

The firewood should not measure more than 30 cm (In very wide stoves it can be longer) and should not be thicker than a man’s forearm. Using 2-3 pieces of wood every time you fire up the fire will give the best combustion.

4: NEVER try to “fire over”. Wood must have air in order to burn correctly. Limiting the air supply will result in the wood emitting gases but these will not ignite. Instead, they will pollute the environment, the stove and the chimney.

5: Go outside and check – The smoke from the chimney should be almost invisible – If there is too much smoke and it smells nasty, you are probably doing something wrong.

The basic component of any wood-burning stove is the combustion chamber. In order to achieve a high combustion temperature it is necessary to insulate the combustion chamber. Normally, Vermiculite is used. This is a light material which, among other things, contains rock material/moler earth. Sometimes fire-resistant rock is used instead.

Any combustion requires oxygen, this can be provided in a number of ways:

The primary air at the bottom of the combustion chamber.

The secondary air or scavenge air over the glass/door – also called the air wash system. The air for the air wash system should preferably be heated.

Tertiary air, or mixed air, which is supplied through the holes at the rear of the stove, just above the firewood. The tertiary air should preferably be heated.

The primary air makes it easier to ignite the firewood. However, it is important that the primary air supply is closed off once the flames have taken hold.

The secondary air, or air wash system air has a basic function besides supplying the air for combustion. The air flows down over the glass and prevents the formation of condensation and soot particles on it. This reduces the formation of soot considerably.

The tertiary air creates turbulence in the combustion chamber and helps the air and gasses to mix better whereby more complete combustion is achieved.

Smoke baffles

Vermiculite of fire-resistant rock has an insulating effect but, of course, the heat from the flames needs to be transformed into heat in the room. Therefore, the smoke in the combustion chamber is converted via one or more smoke baffle plates. The flue gases come into contact with the stove’s steel components and these are heated up. The heat goes through the steel plates on the outside surface of the combustion chamber and the heat is transferred via the convection of the stove into the room. In addition, some of the heat on the glass is released into the room as radiation heat.

Via this baffle system, the temperature is reduced from 700-750°C, to an average of around 250°C before the smoke goes out into the chimney.


A stove’s ability to burn off flue gases and its ability to cool them down and transmit the heat to the surroundings is an expression of the stove’s efficiency.

A modern stove has an efficiency level of around 80%.

An open log fire has an efficiency level of around 20%.

A fire has an efficiency level of around 10%.

The easiest way to do this is with a vacuum cleaner with a soft brush attachment – avoid scratching the stove. Alternatively, you can use a dry or tightly scrunched up cloth or a soft brush. Never use a wet cloth or similar, since water and cleaning agents can attack the lacquer and lead to the formation of rust. The paint used on the stove is not corrosion-resistant.

Cleaning the glass

Clean the glass with a dry cloth as required. If there is still soot residue on the glass this can be removed in one of the following ways (the stove must be cold):

1: With a special liquid glass cleaner.

2: With a piece of moist kitchen roll dipped in the uppermost white ash and used to scrub the glass. Lastly, dry it off with a piece of dry paper. Make sure that there are no impurities in the ash which can scratch the glass.

Insulation – vermiculite

Over time, the combustion chamber’s efficient but porous insulation can get worn and damaged. If the baffle plate cracks, it may lead to the secondary air being distributed incorrectly in the combustion chamber and it should therefore be replaced. Should the side panels crack, this will have no impact on the efficiency of the stove. Side panels and baffles should be replaced when they wear away to around half of their original thickness.

sealing bands

The sealing band should be replaced as and when required, i.e. when it looks worn out or when you suspect that the stove is no longer air-tight. It may be necessary to do this once a year, or perhaps every five years, depending on how much the stove is used.

Tips: You can check the air-tightness by jamming a piece of paper between the door and the stove. If the paper can be pulled out easily (and without any resistance), this may indicate that the door on the stove is not completely air-tight.

Lubricating the hinges and closing mechanisms

Hinges and closing mechanisms on the door should be lubricated once a year. Use a heat-resistant lubricant.

Painting the stove

Over time, the paint can become worn, or the stove can get scratched accidentally. It is relatively easy to remedy this damage by using Senotherm Spray (it can be purchased from the dealer ). This spray is the original heat-resistant lacquer used by the manufacturer to paint the stove. Be aware that the stove may smell again when the paint hardens and you fire up for the first time after you have applied it.


The wood-burning stove should undergo a thorough maintenance check once a year.

This check should include:

– Thorough cleaning of the wood-burning stove

– Lubrication of the hinges with copper grease

– Checking and, if necessary, replacement of the sealing bands

– Tightening and, if necessary, adjustment of the handles/door

– Checking and, if necessary, replacement of the heat-insulating material

– If necessary, this check can be carried out by a dealer

Use only original spare parts.

Problem: soot has formed on the glass.

Cause: Is the temperature in the combustion chamber too low? Is the wood wet?

Is the air supply opened sufficiently? Are there enough embers? Is there sufficient draught in the chimney?

Problem: water is running down into/over the stove.

Cause: Condensation from the chimney, wet wood, the temperature in the stove and the chimney is too low.

Wet wood has been used for firing up, there is insufficient wood or air.

Problem: there is no heat coming from the stove.

Cause: Is the air supply opened fully? Is the wood wet? Is the wood too old or dried out?

Has soot formed on the chimney and stove?

Problem: you can’t get a flame going in the stove.

Cause: Are the baffle plates positioned where they should be? Is there sufficient draught in the chimney? Is the wood wet?

Has soot formed on the chimney and stove? Have the firing up instructions been followed properly?

Problem: it is not possible to regulate the stove, it is still burning even though the air supply has been closed off.

Cause: The stove is not water-tight. Firstly, check whether the sealing bands on the door and the ash drawer are intact and positioned correctly. Contact the dealer.

Problem: there is a smell when the stove gets hot.

Cause: The paint on the stove is still hardening. To overcome this as quickly as possible it is important that you allow the stove to get really hot the first few times it is used. The paint is not wear-resistant until it has been really hot. Following a summer break, there will often be dust, cobwebs and spiders in the cavity of the stove, this can also cause a smell when it is first fired up.

Problem: the glass is cracked.

Cause: If the glass cracks on the first or second time it is fired up this is reasonable grounds for making a claim. Before the glass is re-inserted – check whether there is any welding slag or other defect that has caused the glass to get wedged in.

If the glass cracks later on this is not normally accepted as grounds for a claim.

Problem: smoke comes out when the door is opened.

Cause: Has the door been opened too quickly? Do not open the door until the wood has burnt down to embers. There must not be any visible flames. Is the wood wet? Is there sufficient draught in the chimney?

Problem: the glass has turned white.

Cause: This is due to the glass overheating. It happens, for example, if the stove has been fired up too rapidly, with open start-up air/primary air or if unsuitable fuel has been used.

Problem: the stove is making a noise.

Cause: When steel and iron expands rapidly when it gets hot. This places a strain on the welds and joints which sometimes causes a highly audible sound. This is completely normal and quite harmless – it is not a fault or grounds for making a claim. In very rare cases, when the noises can be classified as a a loud “bang” or “pop”, it may be a good idea to ask the dealer  for advice.

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