My parents have a fire stove like those ones in their house, built almost 30 years ago.
Not a common design in the country they live but apparently it is in Switzerland where they worked for many years before. Very efficient indeed.
This is also common and very old tech in all the colder countries in Eastern Europe but obviously electricity has taken over. I'm even a bit surprised because I'm having a hard time thinking how else would you hear your house but probably it's enough in milder climates to not store the energy like that.
It is a milder climate but still cold winters. People usually have small wood stoves or electric space heaters. It's just they're all not very efficient when compared to these masonry heaters.
