Im fkn stuck on this now until i get some sort of closure lolFor quite a few years I lived off grid and heated shower water in the summer in black jugs enclosed in a tiny greenhouse I made for that purpose. Water would get so hot you needed welders gloves to move the jugs some days. 3 gallons in a hand pump shower did the trick.
If it rained, you didn't hug the missus so much or you did the tea kettle on the wood cookstove thing to wash the important parts.