Those arebsone really creative ways to generate heat. I have always wanted to see the compost pile in action like that. Maybe because I live in suck a cold climate I can't picture utilizing the bath tub ideas but I do think they're clever. Maybe a summer novelty for me. -Aimee
I plan to make one one of these days. I'm in a cold climate also but I've seen people make them efficient enough to work as hot tubs during winter.
Hot tubs?! Now you're speaking my language! -Aimee