[blacksmith_tb]

It's a very large teapot cosy, in other words. Seems reasonable, though obviously you still need some way to bring the pot up to temp (for that cast iron, induction would be efficient if not low-tech).

[RankingMember]

Yeah, when I think of a cooker, I think of something that heats something up, not just keeps it going.

The stove with one burner dropped down [1] seems more practical, not requiring a separate device/extra step.

[1] https://krisdedecker.typepad.com/.a/6a00e0099229e8883301a3fd...

[blacksmith_tb]

I wonder if you couldn't get similar efficiencies by insulating the walls and lid of the pot itself though (and that would work on any stove, not just one that had a sunken burner of a fixed diameter). Choosing a good material for high-temp insulation might be tricky (without making the wall thickness high) but I for one would be happy to have an nice Ti + aerogel pan... (Ti does work on induction too!)

[dudeofea]

less oven space, need to replace entire stove, made in a factory and not at home.

It is cleaner perhaps and more purpose-built. But I would not call that practical.

[druadh]

They do mention that in the article "doubles the efficiency of any cooking device because it shortens the time on the fire"