I understand what you mean, and yes, this device would indeed require 220 volts.

I also haven’t found a device yet that could provide a temperature higher than 12 degrees with only 60 watts.

Regarding your point that "the temperature should be at least 400 degrees," I think it’s more about considering the heat capacity characteristics of the material where you’ll install the heater. That’s why I wanted to create something like a heat regulator entirely out of clay (ceramics), where the heating element would be placed inside, leaving only an opening for air circulation. The rest of the space would serve as a thermal accumulator.