The Revenge of the Hot Water Bottle || by Kris De Decker :: Low-tech Magazine

"Imagine a personal heating system that works indoors as well as
outdoors, can be taken anywhere, requires little energy, and is
independent of any infrastructure. It exists – and is hundreds of years
old. The hot water bottle could save a great deal of energy and money
without sacrificing thermal comfort."  Read more

Photo credit: Pixabay