I´m just about to finish one in northern Germany, I´m investing every bit of free time to get it lit before the next cold spell.
I dealt with the laws in two ways: Since it´s my first one for testing it´s not in a house but in a 2 room brick workshop that I want to keep warm.
And since all the laws and restrictions refer to stationary fireplaces ("ortsfeste Feuerstätten") I built the combustion unit on wheels. This way it´s more like a big barbecue oven
Here´s a pic of the combustion unit that can be rolled around.
Already tested without mass and working like a charm.
I documented the build with a lot of pictures and some videos starting with the chassis, I hope to put a Youtube video up once the thing has proven its functionality.
The thermal battery however is fixed.
SInce I discovered this kind of heaters I´m totally nuts about them, got both books (Ianto Evans and the Wisners) and Pauls 8 DVDs.
And I´d be happy to connect with other RMH builders in Germany. Maybe there´s a way to get them established here.
And even though my first heater is not completely finished (I just started to mortar the bench after a lengthy chimney liner install) I´ve got the second already planned in my head. This will be more of a micro batch rocket instant heater without mass, for sure on wheels again.