In 2015 I was living in a van, and using a gravity fed shower. I heated my water using various flat black painted containers; from soda containers to gallon supermarket drinking water jugs. I used a fish tank thermostat, and back then I could not crack a 100 degrees. Today; life is very good. I have prepared Echo pump sprayers to provide family, and friends for life without running water. I have painted 40 plus windshield washing fluid jugs with the flat black. The thermostat is now well over 110. I am that good at this process, or is the SUN getting hotter?