I thought maybe food for this, but it's a central heating question also. Love these beasts. Ran one in the UK for twenty years burning wood and coal.
esse.com/news/the-new-esse-990-ch/
Not this exact model but a long the same lines. Is there a Polish equivalent? If so can they run the heating? Is running the heating like this not a good idea in Poland? What are the options off-grid? I've tried searching but only come back with similar from Bulgaria. From some of the magnificent room heaters I've seen in Poland, I'm sure there must be something along these lines.