When selecting the appropriate Bullerjan model, it basically has to be considered how big the room is that has to be warmed and your own personal usage.
The mentioned values in the table below are valid only if you want to use your Bullerjan as the sole heating for the room where it is installed.
If you want to use your Bullerjan as an additional heat source and the optical beautifying of your living area, you can set up each model in principle.
Please contact your chimney sweep before buying who can as an expert give you valuable tips.
Nominal heat output of stoves in general depends on the amount of wood used and is defined in kW (kilowatt). This output is a calculated average value in the form of an average heat output per burned unit.
A thumb rule is: about 0,08 – 0,15 kW/h per m² at a normal ceiling height of 2,50 m.
This value may vary according to place of installation, geographical location of your house, room conditions and type of chimney.
Besides the volume, the level of insulation (floor, wall, window, roof) of the room(s) to be heated is important for the calculation of the necessary output. Please consult your specialized Bullerjan retailer and your chimney sweeper regarding the approved and required heat output for your specific room situation.

The following table is a first indication for the selection of your Bullerjan stove:

Level of insulation
very good
Level of insulation
Level of insulation
3,9 - 5,0up to 70 m²up to 55 m²up to 40 m²
6,0 - 8,0up to 100 m²up to 75 m²up to 60 m²
up to 150 m²up to 115 m²up to 85 m²
14,2up to 210 m²up to 160 m²up to 85 m²

Regardless of the results that a chimney calculation program outputs after entering the present values, it has to be taken into consideration that in the cold state the chimney exhibits a basic draught/ under pressure in the amount of at least 5 Pascal (Pa).
In the event that the basic draught is too low, flue gas can ingress in the installation room, in the course of the initial combustion.
The maximum draught that the chimney exhibits during the heating operation must not exceed 16 Pascal (Pa). Insofar as the draught is too high, the wood burns too quickly and the oven cannot unfold its full heating and environmental qualities.
In the extreme case an excessively high draught in the chimney results in damage of the oven and in particular of the catalytic converter (for models FF15 only). Furthermore, ash from the combustion chamber can under these circumstances ascend into the catalytic converter (for models FRF15 only), which in turn can cause malfunction of the stove and can as a consequence lead to flue gas leakage into the installation room.
A remedy in this case is an automatic draught regulation of the chimney. Please contact your authorised Bullerjan® – trade partner or chimney sweeper.