I consider my ability to enjoy a hot shower every day one of the greatest luxuries in life and a great achievement of science and civilization. It's a pleasure I never take for granted, and even understanding the environmental costs, one I hope to never surrender. But a stray thought made me wonder if we could redesign the typical shower to improve its efficiency.
When I shower on a chilling fall or winter morning, I notice that even while surrounded by the heat of the water I'll still feel a chill in my extremities thanks to the cooler air beyond the shower doors (or curtain, if I'm downstairs). While observing this phenomenon this morning, I wondered what would happen if the shower and I were suddenly transported to the South Pole, with the shower still, somehow, in operating condition, pumping an endless supply of hot water. How long would it take you to freeze to death? Shower doors provide virtualy no insulation, being glass; a curtain wouldn't be much better. My own shower is open at the top, since the doors don't extend to the ceiling. Even given an unlimited supply of hot water, I imagine the exothermic reaction would quickly suck most of the heat out of the shower and into the frigid Antarctic, dooming the showering human to an agonizing death.
Barring the intervention of sadistic deities or advanced aliens, such an event is, I admit, unlikely. But it does make me wonder about all that wasted heat. Could we design showers to trap all that waste heat and pump it back into the hot water tank somehow? Or distribute it through the vents to help heat the home? Would it be cost-effective to do so? Do they already do this in the top-secret underground lairs of shadowy spy agencies?
Could we design and build a more environmentally friendly, less wasteful shower...one I don't have to feel guilty about using?