Stupid simple auxiliary house heater based on sun and aluminum cans and little hacking around.
I came across this ridiculous life hack I want to try in fall/winter.
So need to collect some cans since we don't buy any of them; I guess I will be looking out for the cans now.
I also keep thinking of other potential usages of this "solar can heater".
One can heat a hive or a green house, I suppose.