We are choosing a fireplace or stove for a wooden building and a low-energy house

Output – the alpha and omega of today's homes

The days when manufacturers of fireplaces and stoves competed to see whose product would have a higher output (often up to 20 kW) are long gone. Thanks to technological advancements in the materials used, there has been a significant improvement in the insulating properties of newly built houses, both masonry and timber. Their thermal losses now range from about 5-9 kW, or even less.

The output of the fireplace or stove should correspond to the thermal loss of the house. This so-called "Nominal output" is required to be stated in the technical data sheet of the appliance and is given as a specific value in kW (e.g., 8.2 kW). Designers very often use this value as a benchmark when considering whether a particular appliance is suitable for the house. And here we would like to provide some clarification.

The nominal output is a value measured in a laboratory during emissions testing. It is very similar to how cars are tested. In order to achieve the best emission values, the manufacturer uses nearly perfect wood – completely dried, without bark, without knots, with a computer-controlled chimney draft, an ideal air supply for combustion, resulting in nearly perfect burning.


A regular user in their home has no chance of achieving such a high level of combustion efficiency. Therefore, when assessing the suitability of a given appliance for the house, we recommend keeping in mind that the real output of the fireplace or stove in the house is about 30% lower than the stated "Nominal output" in the technical data sheet.

Construction readiness of the house

The basic elements of construction readiness apply to houses of all types – concrete, masonry, and timber. It primarily involves sufficient load-bearing capacity and rigidity of the floor under the fireplace or stove. There should not be any underfloor heating in that spot, nor soft layers such as polystyrene, and it should be non-combustible (like tiles, concrete, metal, etc.), or a non-combustible layer should be placed on a combustible floor, such as tempered glass.

The diameter of the chimney and air supply pipe, with few exceptions, must correspond to the diameters stated in the technical data sheet of the appliance. We therefore recommend that the customer selects their desired model of fireplace or stove at the beginning of construction and sizes the chimney and air supply pipe accordingly.

Installation of fireplaces and stoves in timber buildings

Timber buildings present unique specifications. Installing fireplaces and stoves in timber structures requires thorough preparation of the house. It is not just about the aforementioned load-bearing capacity of the floor. A key issue is addressing the fact that the walls are deemed combustible. Therefore, the appliance must either be placed sufficiently far from the wall (sometimes up to 50 cm), which is often undesirable, or it’s necessary to choose an appropriate method for insulating the wall in question.

A typical example of a solution can be the model of a wall-mounted design fireplace Rocal MINI DROP, which is imported to the Czech Republic and installed by the company FLAMEN. The fireplace is metal, hot, and additionally wall-mounted. At first glance, it might seem impossible to install it in a timber building.


However, the solution is elegant, inexpensive, and simple. It consists of building a brick false wall about 1 meter wide in front of the wooden wall. This false wall resolves all problematic moments at once:

1. It creates a thermal protective layer between the fireplace and the wooden wall
2. It has sufficient rigidity and load-bearing capacity to support the weight of the fireplace fixed to it
3. It conceals the air supply pipe

The false wall can then be clad or painted in a color different from the rest of the interior to further emphasize the design of the fireplace.

Although it may initially seem that it is impossible to install a fireplace or stove in certain houses or interiors, in most cases, solutions can be found in cooperation with a professional company.

For technical support or collaboration, do not hesitate to call or write: +420 226 886 473, [email protected], www.flamen.cz