Insert 3 - Metalfire Optimum 700

Our current old Rocal insert is not very efficient. According to a calculation engineer Jansen found on the internets, so it is true, you need to divide your room's volume in m3 by 14, to find the number of kilowatts necessary for heating. For us that is 9,2kW.  You should add 1kW for every big window, but I did not do that. We're in southern Spain you see.

I wonder if the old insert has that capacity.  I think it's intended more for a "fun" fire, not to seriously heat a room, let alone a house. The heat exchange is at the back and top of the metal box of the stove, where an airflow is maintained by a ventilator.

The rest of the heat escapes through the chimney. Looking for a more elaborate heat exchanger in an insert "Kalfire" was found, and later "Metalfire" from Belgium. Kalfire has a front glass that slides up, Metalfire has a door with a handle.

Here is the schematic for a Metalfire Optimum.   Lots of zig-zag plates that take over the heat from the hot gases:

Three versions:

The first is the plain insert, the second has a "convection mantle",  the third has a block of soapstone for heat storage and slow dissipation for hours.

The insert must be inserted in an enclosure,  like this:

Airflow is by convection only, there is no ventilator. The convection mantle makes installation even easier.

Interior of the fire chamber can be a combination of Skamol (vermiculite like ceramic material) and metal, and ashpan:

All metal interior

Metal bottom, skamol side and top

All skamol

The metal versions can also be colored, terracotta, gold, ...

See for yourself what versions there are:   https://www.metalfire.eu/en/products/wood-fireplaces/optimum#finishes

They even provide a 3D model, that was immediately incorporated in engineer Jansen's LiveHome3D drawing: