[infinet]

Sticking head into a barbecue oven for 10 minutes might get rid of lice, but expecting cooking smoke kill bugs is absurd. People use the three stone and hearth fire not because they want the smoke, but because they do not know better. Combustion is a complicated process, it generates CO2, H20, CO, H2, CH4. The higher the temperature, the more thorough the burning. It requires the right amount of air, enough to burn all the biomass, but not too much that carries heat away thus lowers the temperature. Higher temperature also transfer heat more efficiently to the cookware. Only a well designed stove can do that. These are not things that can be figured by meditating in front of an open fire.

Saving fuel is a matter of life and death in the ancient world. Winter is brutal to the poor largely because gathering fuel is difficult, especially in areas that have supported large population for centuries.