Need to know about fireplaces

Fireplaces and stoves


Very decorative solution of heating – wide assortment of stoves and fireplaces. Fireplaces and stoves are recommendable from because of power economy.


Effective maintenance of fireplaces pays more and more attention. Creating projects of heating systems, become economic heating system together with great visual effect.


A coefficient of efficiency for the traditional, open fireplaces with bricked furnaces don’t exceed 15-20%, heat return of fireplace is possible to increase, adding recuperators or heat excange cameras, different kind of constructions. Usually steel plates are used, but they can lose shape under the high temperature. Cast iron is the only material, which is resistant for high temperatures and saves its shape during repeated heating and becoming cold. It’s a way how a coefficient of efficiency increases till 40-45%. That’s why fireplaces closed cast iron inserts reach a coefficient of efficiency 75% and even 80%.


1. heat isolation

2. hot overhead wires to other premises

3. inflowing hot air in the room  

4. flue pipe  

5. heating of cold air before flowing into the insert  

6. heat collector  

7. hot inflowing air deflected along the glass to keep it clean

8. air feeding from the outer







Due special kind of cast iron fusion, this kind of stoves and fireplaces starts producing of heat already after 10-15 minutes (for ordinary tile stoves this paramter is 1-1,5 hours).


Obtaining fireplace with a closed cast iron insert, is possible to use it as air heating system for several premises together – both in a flat and in a house. Such a solution is possible, using heat collector over the insert and adding to it the isolated hot overhead wires. Hot air is flowing out by the tubular hot air channels to the other premises, whom is preferable to provide in a project of premises.  


For more complicate heating system pumped air circulation by using some special heat-resistant ventilator is necessary. In every special case, especially, if it’s the only way of heating, the specialists are making serious calculations, as for any kind of heating system, to know the prompt thermal losses in the premises and thermal resistances of building materials as well as a power and actuators of insert and ventilators.


Of late years more and more the fireplaces with built-in insert, which operates as central heating boiler, are used. This kind of insert is possible to connect to the already existing heating system and also to connect with a separated gas or liquid fuel boiler, which opearates automatic. The main advantage is following: water accumulates the heat much much longer than the air.


What’s important, choosing and installing stove or fireplace?


The power of a heating plant


The important condition should be considered – the power of a heating plant is given in kilowatts, but the power, which is necessary for the heating of premises, is calculated for the whole cubic capacity of premises. Choosing or buying the stove or a fireplace, calculation is following: 1 kilowatt of power for heating approximately 30 cubic meters of room’s capacity. This means, that for a room of 10 m² with its height of 3 meters, 1 kilowatt of power is necessary. Some companies specify only, how much square meters of room can be heated, ignoring the height of the ceiling.


Important aspects are: chimneys (flues), fire security, heat isolation and the choice and processing of fuel.


Chimney (flue)


Before to start installation works of heating stove or fireplace, first of all, is necessary to make sure that a chimney, to whom will be connected a heating plant, conforms with all fire-prevention standards, which are in force in the Republic of Latvia. In case there was already connected a stove or wood cooker to the chimney, then some additional submission is unnecessary. A wood cooker can be teared down and install there a stove or fireplace, only a chimney-sweeper verification is necessary. In case a heating plant wasn’t connected to the chimney – is necessary to enter it in the room’s inventory’s plan as well as an act of chimney-sweeper about the condition of a smoke channel is a must. A chimney should be placed by a heating plant or maximally close to it. Minimum of cross-section area for a chimney is 27 cm x 14 cm (desirable 27 cm x 27 cm). If a circular tubular chimney is builded, minimum diameter should be 20 cm (for the smallest inserts 18 cm). Minimum connection of the closed insert is in the height of 2-2,5 m from the floor, but maximum possible – not closer than 30 cm from the ceiling. Any kind of connections between the floorcovers or attics are inadmissible – a connection must take place at the same floor where a fireplace or a stove lies. A chimney shouldn’t be lower than 5 m, measuring from the insert, and it should be, of course, vertical, though a few splay elements are admissible, but not more than 2 turn-offs, in addtion those turn-offs cannot be placed one above another, some kind of vertical element should be between them. The usage chimneys of self-constructed , of unknown origin, without certificate and laboratories tests is forbidden. The building, where is necessary reconstruction or improvement of a chimney, we recommend to put into the already existing, old chimney a metal chimney, which is made especially for this reason. In this case a casing (jacket) of old chimney serves for a heat isolation and a carry wall of a new chimney.




Fire security


Secondly, you should make sure about a fire security of a floor, walls and ceiling materials. In case of necessity the special heat-resistant, isolating additional materials should be used. A base under the planned fireplace should be embedded in concrete and accordingly fixed. Placing it in a room, an inflow of a fresh air for the burning process should be provided. A special attention deserves the hermetic glass packet windows, because burning a fireplace, air from a room is used and in a case of a lack of fresh air inflow a traction in a chimney can go into the opposite way, and then a chimney will work as an air inflow, this means together in a room through the insert will reach the smoke and grim. To prevent such kind of negative effect, a connection of a airflow from the outer wall to the fireplace is recommended. A providing of a fresh air inflow is compulsory requirement. You should remember, that in a direct nearness of a fireplace any kind of electrical installations (cabels, wires, rosettes) projects are forbidden, or they should be specially isolated.


Heat isolation


Certainly should be considered a isolation of a room. All the calculations of manufacturers, mentioned in a technical information, are provided for the premises without the large losses of heat through the walls, windows, a floor and ceiling. The magic will not happen, if a room is badly isolated, through the windows wind is blowing – you will heat, to add a wood – heat will not be. If a room isn’t warmed properly, any kind of mechanism becomes uneffective. But if it’s done properly, a scheme is following – first of all, a room should be warmed till the necessary temperature during a few hours, further amount of heat is needed to compensate the losses of heat and to keep desirable temperature. And here gain the calculations start – how much kilowatts of heat a room loses during 1 hour. The bigger those losses are, the bigger power should provide a heating plant. If the heat losses are small, you can shut down the air feeding and to heat in a slow regime. So more economic is to create a heat isolation properly and then to save money on heating!


Fuel and processing


The fireplaces with the same amount of wood can burn as well 3, 4, or even 8 hours depending from the heating regime and a classification of insert. To calculate, how much fuel is necessary for a year, the following formula can be used: 0,03 m³ of wood for the 1 m³ of heating space. For example, if a living space is 100 m² and a height of ceiling is 3 m, then multiplying cubic capacity of a room with 0,03, we’ll become 9. So for the heating of this room is necessary 9 m³ of wood in the year.

A wood should be in a good quality and also well seasoned. Well seasoned wood is a wood, which is stored in a well ventilated penthouse from 18 months till 2 years. Permissible amount of humidity is 20%. Heating with woods with a humidity over  20%, rapidly decreases a heat return of the insert and due intense regime of condensation a glass of insert and chimney become covered with soot fast. Recommended to use a wood from a leaf-bearing tree because there’s the lowest content of gum. From the most availble wood in Latvia the biggest heat return has oak (coefficient 10,00), comparing to this – ash-tree has 9,60, maple 8,75, birch-tree 8,33, black alder 7,10, aspen tree 5,00, lime-tree 4,20.