Good to know

 

I have seen these "heaters" earlier somewhere else, but this looked simple enough and in these days of uncertainty and high energy prices it could be used to heat a small room, garage, bathroom, supplemental heat, etc.  There may be better designs out there, but this is a good starting point. A couple of commentors mentioned placing pennies underneath the pot to elevate it and allow for better airflow, etc. for example. I am sure there are mods for improvement and efficiency, but this would work and especially in pinch.