Certain types of fireplace stoves and inserts can be equipped with accumulation elements - bricks, panels, rings. During active heating, excess heat (which would otherwise be lost through the chimney) is accumulated and released after heating stops. Accumulation elements are characterized by a high density of up to 4 kg/l.

Ash is the loose, unburnt remains of flammable solids - fuel. White or light gray ash means the combustion process is efficient.

Due to the relatively high content of potassium in wood, wood ash contains a considerable amount of potassium carbonate (potash), which was produced from wood ash in the past. Today, wood ash is considered a good potassium-based fertilizer.

This is an integral part of all devices for the combustion of solid fuels. It is used to collect the unburnt residue (ash) created during the combustion of wood. The ash drops into the ash tray through the grate. Ash trays for fireplace stoves and inserts are removable. Always make sure the ash tray and its contents are cold before emptying them.

An authorized dealer is a person or company with the required training and authorization for the sale and assembly of STORCH products. You will find a list of authorized dealers on our website at www.storch-kamine.de/en/


The supporting welded body of the fireplace stove or insert, onto which other parts are mounted, such as the furnace door, wood box door, hinges, ceramic, stone or other accessories, etc.


All Storch fireplace stoves and inserts are equipped with CAI, sometimes called “external air intake”. In practice this means that the heating unit can be connected to external air intake or air intake from another room via a vent (which must be structurally prepared - from under the floor, through a wall, from the cellar, etc.), making combustion independent of the air in the room where the fireplace stove or insert is installed. This solution is especially useful in airtight buildings and buildings with recuperation. See also Low-energy and passive houses.

Carbon monoxide is a colorless and odorless gas that is not an irritant, but is very dangerous and highly toxic to humans. It is lighter than air but mixes with air. Carbon monoxide is created through imperfect combustion, when the combustion temperature is too low, i.e., the period of combustion in the combustion chamber is too low or there is insufficient oxygen- air intake. Even a very small quantity can cause serious medical problems if inhaled.

Cast iron is made of pig iron in combination with cast iron and steel scraps and the addition of coke and limestone. Due to its high resistance to heat and pressure, it is used for highly stressed parts in Storch fireplace stoves and inserts that are in direct contact with the fire, such as the grate bars, grate, stops, flue gas outlet, etc.

Glass for fireplace stoves or inserts is made of special transparent ceramic, guaranteeing the required high temperature resistance. Standard glass cannot be used, because the glass in fireplace stoves or inserts is in direct contact with the fire in the furnace and this would immediately lead to its damage.

Our fireplace stoves and inserts are equipped with ROBAX® ceramic fireproof glass by SCHOTT, which is transparent and offers extremely high temperature resistance. This type of glass has low thermal expansion and is thus used in environments where it is exposed to high temperatures, especially the doors of fireplace stoves and insert, safety screens for open fireplaces, fireproof cooking and induction plates, etc.

The lining of the combustion chamber is called “chamotte” or “chamotte lining”. Chamotte is a fireproof substance used for the lining of furnaces that need to resist high temperatures (around 1650°C). During production, chamotte is fired at very high temperatures, giving rise to a reaction in which individual components of the substance are connected by a ceramic bond. This bond provides chamotte with excellent thermal resistance, low thermal expansion and good accumulation properties, all of which are important for the lining of the combustion chamber; these beneficial properties cannot be matched by other materials used for this purpose such as vermiculite or refractory concrete. Another advantage is its resistance to corrosion, a property that cannot be matched by cement-based lining. Admixtures of various elements provide chamotte with the desired color – white, yellow, gray, but typically rusty red to black.

The chamotte lining itself is used to ensure that the direct heat of the flame is separated from the steel plate of the furnace. Storch fireplace stoves and inserts always use genuine chamotte in its best form – pressed/molded bricks.

There are various types of chimneys, including brick chimneys, stainless steel chimneys, and modular chimneys. The condition of the chimney unit, its structural design and proper connection to the fireplace stove or insert has a fundamental impact on the correct operation of the product. The correct function of fireplace stoves or inserts requires a suitable chimney (minimum diameter, draft, seal, etc.). The owner of the property is responsible for the condition of the chimney, and hence the owner is also obliged to arrange regular inspections and maintenance.

Negative pressure is created in the chimney due to the chimney effect, which causes an upward flow. This flow is essential for the removal of flue gases - smoke created by combustion. The chimney draft is created by the different vent temperatures between the upper and lower aperture of the chimney. The chimney draft is also affected by maintenance - if the vent is clogged, it cannot pull well - and external conditions in the transition period, respectively, the chimney draft (flue gas extraction from fireplace stoves or inserts) may decrease at higher outdoor temperatures above 15°C, on rainy and damp days, or in case of high winds.

A suitable chimney (minimum diameter, draft, seal, etc.) is a prerequisite for the correct function of fireplace stoves or inserts. Before installing a heating unit, we recommend discussing the setup with a chimney sweep. Chimney specifications are listed on the technical data sheet for each Storch fireplace stove and insert. If the chimney draft is too strong, the installation of a suitable chimney flap or chimney draft regulator is recommended. Excessive draft can cause operating problems due to, e.g., combustion being too intense or high fuel consumption, and consequently lead to permanent damage of the fireplace stove.

A chimney flap can be installed in the chimney or flue at its connection to the fireplace stove or insert. This flap is used to regulate the draft when it is too high or to stop air circulation when the heating unit is not in use, so that the natural draft of the chimney does not cool the building and drain away heat.

Combustion air is supplied to the furnace and allows the burning/combustion process. By regulating the amount of air entering the combustion process, we also control the speed of combustion. A lack of combustion air in the combustion chamber will cause imperfect combustion. See Primary and secondary air.

A manual controller or automatic regulation device for the control of combustion air intake – primary or secondary.

Through combustion, i.e. the action of heat, wood is broken down into combustible gases, which are subsequently mixed with oxygen (combustion air) and burned. The creation of a visible flame demonstrates these gases were correctly burned. The lighter the flame - yellow and white, sometimes blue - the better the quality of combustion. Dark yellow or red flames signify imperfect combustion due to lack of air and consequently mean that the created gases were not completely burned and a large amount of these gases will remain unused and exit the combustion chamber to the chimney.

This phenomenon occurs when, for instance, you roast sausages over an open fire. Otherwise, the wood would be unable to burn.

Convection refers to flow/circulation. See Spread /and transfer/ of heat by convection.


The space between the flue gas outlet and chamotte lining (ceiling) of the combustion chamber through which flue gases (smoke) flow, is usually equipped with deflecting sheet or deflector. This ensures the required temperature at the flue exhaust outlet and, in parallel with efficient combustion, increases the efficiency of the fireplace stove or insert as a whole.

This device is used to restrict air flow and at the same time allows regulation of the chimney draft. Draft regulation is used when the draft of the chimney is too strong and consequently the heating unit has a higher output than needed. Our specialized dealers can provide more information if there are any problems. See also chimney flap


The ratio between the total heat output and intake during the test period, expressed as a percentage. In other words, how much heat energy can be generated by a fireplace stove or insert burning wood with a certain moisture content. The higher the efficiency, the more heat is generated.

The European standard for all built-in solid fuel heating appliances and fireplace inserts, detailing requirements and test methods.

This European standard specifies the requirements for design, production, construction, operating properties (efficiency and emissions), safety, manuals and labelling, including associated methods for testing solid fuel heating appliances for residential areas. This standard applies to appliances with manual stoking. Such appliances heat the areas in which they are installed. If the appliances are equipped with a boiler/heater, they are also used to heat domestic (drinking) water and/or water for central heating. In compliance with the manufacturer’s instructions, these appliances can be used to burn solid mineral fuels, peat briquettes, natural or processed wooden logs, or a combination of such fuels.

All fireplace stoves and inserts operated in the EU must unconditionally comply with this standard.

The European standard for all solid fuel heating appliances for residential premises, detailing requirements and test methods. 

This European standard specifies the requirements for design, production, construction, operating properties (efficiency and emissions), safety, manuals and labelling, including associated methods for testing solid fuel heating appliances for residential areas. This standard applies to appliances with manual stoking. Such appliances heat the areas in which they are installed. If the appliances are equipped with a boiler/heater, they are also used to heat domestic (drinking) water and/or water for central heating. In compliance with the manufacturer’s instructions, these appliances can be used to burn solid mineral fuels, peat briquettes, natural or processed wooden logs, or a combination of such fuels.

All fireplace stoves and inserts operated in the EU must unconditionally comply with this standard.


If the seal of the door or glass becomes damage, either due to degradation caused by high temperatures or due to mechanical wear and tear, or if the furnace door is not fully closed, this leads to air intake that will affect the combustion process in the fireplace stove or insert. This causes uncontrolled air intake and leads to unregulated combustion. In general, one can say that “false” air intake prevents the regulation of combustion, meaning that we can’t increase or decrease the intensity of the combustion process (it always burns the same), as a consequence reducing the efficiency of the heating unit.

Long-term thermal stress caused by overheating can lead to permanent damage to the structure of the fireplace stove or insert.

A fireplace stove is a heating unit independent of the building from a structural perspective, which is the main difference from a fireplace insert. The installation of fireplace stoves is simple, quick, and “dry”. Fireplace stoves come in many shapes, sizes and models and are designed to be installed in various interiors (apartments, houses, recreational buildings, restaurants, etc.). Fireplace stoves can be clad in ceramics, stone or sheet metal. Installation must be carried out by an authorized person.

During the first few heating cycles, the paint on the heating unit is hardened and may smell. This is why it is important not to exceed the maximum allowed heat output of the fireplace stove or insert. During the first 4-5 heating cycles, ensure good air circulation in the room with the heating unit and insulate it from other rooms to prevent the smell from spreading; also, remove any small animals and birds from the area with the varnish vapors. It is also recommended you turn off water aeration in aquariums during this period. As soon as the paint is fired, the smell will disappear.

See also First Operation of the Fireplace Stove or Insert in the General Installation and Operating Manual for Storch Fireplace Stoves or Fireplace Inserts.

A pipe, usually made of sheet metal, connected to the flue gas outlet through which flue gas (smoke) flows from the appliance to the chimney.

The flue is an area at the top of the fireplace stove or insert through which smoke flows. In general, deflectors and other elements are located just above the combustion chamber and these are used to ensure that heat does not escape into the chimney, hence increasing combustion efficiency. Flues for all Storch products are designed and constructed to maximize efficiency and minimize the emissions of fireplace stoves and inserts.

These are the products of combustion which leave the appliance through the neck and flue gas outlet into the flue shaft /chimney/.

A top or rear, usually cast iron outlet, intended for connection to the flue shaft, which allows flue gases to flow freely to the chimney.

Fuel is material in which energy is stored, where this energy can be released in the form of heat through oxidation in the form of burning/combustion. Wood is the most economical and widely used fuel for fireplace stoves and inserts.

The area of the combustion chamber in the fireplace stove or insert where fuel is burned at high temperatures. The furnace of Storch fireplace stoves and inserts is shielded by chamotte lining in order to shield the metal plate of the furnace from the direct heat of the fire.


See Ceramic fireproof glass

See secondary air.

A glass/sheet metal floor mat is used to protect the flammable surface of the floor in front of the heating unit, specifically from falling sparks or other hot material from the furnace. We can supply glass/sheet metal floor mats in various shapes.

Part of the internal, bottom area of the furnace where fuel is placed and from which solid combustion residue falls into the ash tray or ash pan. Combustion air also flows through the grate. The grate /grate bar/ is a highly stressed component in direct contact with the fire in the furnace, so Storch makes these using high-quality cast iron.

See also Cast iron.


High-strength sheet metal is formed by alloying. Alloying (from lat. Ligare = to join, bind) is the metallurgical process in which certain alloying elements are mixed with a primary metal or existing alloy in order to improve its usable properties, especially mechanical properties and hardness. The production of steel is a typical example.

Alloy steel is created by the addition of other metals (elements) to low-carbon steel. The most common are molybdenum, manganese, nickel, chromium, vanadium and silicon. We differentiate between low-alloy steel (up to 4% of other metals) and high-alloy steel.


See product label.

Standard projects designed as low-energy or passive (family) houses, characterized by very low energy consumption for heating. No high-tech equipment is used in such buildings, but the reduction in heat loss is achieved through thorough insulation, which can maintain pleasant temperatures in rooms throughout the year.

If you wish to install a fireplace stove or insert in a low-energy building, an external air intake is generally required for the heating unit. Please consult this with your dealer before purchasing a heating unit.


The total heat output of the appliance/heating unit designated by the manufacturer and achieved under test conditions using the given test fuel. Nominal heat output is specified in kilowatts kW. It designates the amount of heat transmitted by the fireplace stove or insert to its surroundings per hour (kWh) while burning a certain amount of fuel (wood).

The nominal output is the output at which the fireplace stove or insert was approved in a test laboratory. The efficiency and emission values listed on the technical data sheet in the operating manual and on the product label all apply at this nominal output.


The construction of Storch fireplace stoves and inserts guarantees sufficient primary and secondary combustion air intake into the chamber.

Primary air, used to start the fire, is supplied directly to the burning fuel (flames) in the furnace, usually via the ash tray and grate through the lower side of the door, and is used for the primary combustion reaction. By regulating the amount of air entering the combustion process, we also control the speed of combustion.

A fully opened primary air intake fans the fire, and hence is only suitable for beginning the combustion process/starting the fire. After the combustion process begins and the fireplace stove or insert achieves its operating temperature, it is generally recommended you restrict the primary air intake as much as possible in order to increase combustion efficiency and give preference to secondary air.

The product label lists the basic information associated with the given Storch fireplace stove or insert: the name and address of the manufacturer, serial number (very important for precise identification of the product in case of a warranty claim or when ordering spare parts), and information on output, efficiency and emission parameters of the product – which are important for the chimney sweep.

The metal product label (or self-adhesive aluminum label) is located on the back or in the wood box of fireplace stoves; it can be found below the ash tray of fireplace inserts. See also Serial number of Storch products.


Radiation is a physical process in which a substance radiates energy in the form of electromagnetic radiation. The energy that is emitted by radiation depends on several factors: the temperature of the radiating body, the surface color and surface area. See Spread and transfer of heat by radiation.

Each heating unit not only has a nominal output but also a regulated output - a range of heat that the fireplace stove or insert can deliver provided the correct procedure for stoking and air regulation is followed. This is the range of output at which the fireplace stove or insert operates at correct, i.e. optimal emission values.

Part of the inlets and outlets used to distribute and direct air flow during convection.


Sealing cords of various types, usually woven or plaited, flat, profiled, encased in braided wire, hollow, self-adhesive, etc., are used to fix fireproof glass and seal the furnace doors of fireplace stoves and inserts. This prevents smoke from leaking into the room. These cords are made of special glass fibers and can resist temperatures of up to 600°C. These properties allow sealing cords to be labeled as fireproof by the manufacturer. The sealing cord in the furnace door is often secured in place with stove putty.

Secondary air allows more efficient fuel combustion, which increases the heat output and plays a crucial role in reducing the amount of pollutants that escape into the environment. In parallel, this makes the cold air roll against the inside of the front glass (glazing). Simply put, it helps clean and remove soot from the glass and in general improves the efficiency and environmental properties of combustion. This air is supplied to the area above the burning fuel or the glass from above and is involved in the secondary combustion of fuel.

Fireplace stoves and inserts have the ability to transfer heat through radiation. The healthiest type of heat in relation to the structural design of Storch fireplace stoves and inserts, is heat radiated through ceramics. This type of heat transfer does not increase air temperature but instead transfers heat to all surfaces reached by the radiation. See Radiation.

The serial number of Storch products is a unique alphanumerical 10-digit identifier that is unique for each fireplace stove and insert produced by Storch. The serial number is used to identify individual products and models.

The serial number of Storch products can be found on the warranty certificate, on the yellow manufacturer’s label, and is listed on the handover protocol you received from your dealer after you purchased your fireplace insert or stove. It can also be found on the metal label (or aluminum self-adhesive label) located on the back of the product or alternatively in the wood box of fireplace stoves, or in the area below the ash tray for fireplace inserts. See also product label.

Soot is a dark powdery deposit of unburnt fuel residue, which contains residual carbon in various forms, such as tar. This is predominantly created by burning carbon-rich organic fuels at an insufficient, i.e. low combustion temperature, as a result of which soot accumulates in the chimney.

Soot formed on the inner surfaces of the furnace in case of incorrect combustion, reduces the efficiency of the heating unit. An increased deposit of soot on the glass of the door or walls of the furnace means the combustion process is imperfect. Soot is flammable, and if larger amounts are deposited in, for instance the chimney, they can catch fire and possibly even cause an explosion.

Heat transfer by convection or circulation is based on the flow of air that is heated near the heating unit, gains energy and based on the principle "heat goes up and cold goes down" results in the circulation and flow of this heated air. The movement of individual parts with different temperatures and hence different internal energy levels leads to the transfer of heat.

Use enough fuel and start the fire “from the top”, which will allow the stove to reach its operating temperature without having to open the door and stoke before the first load of fuel burns out. If the process is done correctly, only burning embers will remain in the furnace.

  • For fireplace stoves and inserts with a grate - first put crumpled paper in the furnace, and then kindling and small pieces of wood on top. A solid firelighter can also be used to start the fire.
  • For fireplace stoves and inserts without a grate - only secondary air is used for combustion, so first place wooden logs into the furnace, followed by smaller pieces of wood and finally kindling and paper.

Once lit, let the fire burn freely with open air regulation elements (primary air). Once combustion is stable and the draft is sufficient, larger logs can be stoked without risk of producing excessive smoke. Only stoke the maximum specified amount of fuel, depending on the nominal output of the fireplace stove or insert.

Automatic regulators are smart technological devices - optical (LED) and acoustic signaling for stoking, which control the amount of air intake for optimal combustion based on the temperature of exhaust gases. Automatic regulation maximizes product efficiency, saves fuel and furthermore extends burning time.

Putty which can resist temperatures ranging from -20°C to 1200°C. It is used to repair cracks and joints in the chamotte lining of stoves and fireplaces, boilers, furnaces, chimney flanges, flue shafts, joints in open fireplaces, etc. Stove putty is also frequently used to secure the sealing cord in the door of the combustion chamber. The amount of time required for putty to fully cure depends on the temperature and width of the joint, but is usually around 24 hours.

Stove putty is readily available at specialized stores, or you can purchase it from authorized Storch dealers or directly from Storch.


The deposition of black oily soot in the chimney is caused by insufficient draft, negative pressure in the chimney and the low temperature of the chimney unit. Water vapor, acid and other compounds start condensing on the inner surface of the chimney insert before they leave the chimney. Excess condensation with tar creates a thick substance - creosote, which flows down and damages the heating unit. The next time you begin heating, it will manifest as a strong, pungent chemical odor.

A temperature inversion is a meteorological phenomenon where the air temperature in a layer of the lower atmosphere does not decrease with altitude, but increases instead.

One of the consequences of temperature inversion is a significant increase in the concentration of pollutants from car exhausts and chimneys in the stationary ground air layer. Temperature inversion acts as a retention layer in which pollutants from local heating, transport and other sources are concentrated.

Inversion situations, which may last days and even weeks in some cases, usually occur in the autumn and winter months. They are characterized by low-lying cloud enveloping the lowlands, while mountain areas enjoy clear and warm weather. Inversion usually lasts until the arrival of a significant atmospheric front and associated wind.

Like secondary air, tertiary air is supplied above the fuel and has the same purpose – to mix with and burn combustible gases. See secondary air.


An inflammable insulation material with a temperature resistance of up to 1100°C, but which lacks the ability to accumulate heat. This material is highly resistant to temperature shock and mechanical damage, so it is frequently used as a thermal insulating lining and alternative to chamotte for highly stressed structures in direct contact with flame. See also Deflector.


Never use household waste, flammable liquids, coke, coal or waste such as chipboard, plastics, bags, impregnated wood or wood shavings, chips or pellets as fuel for Storch fireplace stoves or inserts.

Burning these materials not only heavily pollutes the environment but it also damages the fireplace stove (insert) and chimney! In case of a claim or complaint, it is possible to determine whether waste was burned from a sample of the inner surface of the combustion chamber.

Wood is the basic fuel used for Storch fireplace stoves and inserts. In order to achieve the nominal parameters of the heating unit, we recommend using dry wood logs with a diameter of 5-8 cm, a length of 20-30 cm and a moisture content of less than 20% (optimally 10%). A higher moisture content results in energy that should have been radiated in the form of heat being spent on reducing this moisture, and so the wood has a lower calorific value. 1kg of wood with a moisture content of 20% provides about 3kW of thermal energy.

Wooden briquettes are made of pressed pieces of wood or wood pulp, sawdust and shavings (sometimes also small pieces of bark), usually in the shape of a cylinder, without any additives or unsuitable binders. These are machine-dried, which is why they offer a higher calorific value than wood.