A sauna? Sure. But a hot tub? There are very, very few bodies of water that you can submerge comfortably in that doesn't end up being a non trivial amount of e

A sauna? Sure. But a hot tub? There are very, very few bodies of water that you can submerge comfortably in that doesn't end up being a non trivial amount of energy to warm up, much less keep warm. To each his own I guess.