[Daox]

99% of the time we use our upstairs shower (standard stall with sliding glass doors approx 32"x44"). It is tiled on all three sides. One wall of the shower is an outside wall and it has glass block in it to make a window (unfortuantely facing west so you don't even get sun shine in the morning). Its a pretty shower, but really not the warmest unfortuantely.

So, I was thinking the other day, there is plenty of hot water going right down the drain. How can I use this to make a more comfortable shower and/or just put it to use? There are obviously the thin film heat exchangers that work great, but cost a lot of money as they're made totally of copper. So, the idea I came up with is pretty simple and can probably be improved upon quite a bit with input from everyone here. The idea is to stick a tube down into the trap under shower drain, pump the hot water up to the top of the shower, loop some tubing around the top of the shower, punch a bunch of small holes in it, and let it drain down the sides of the shower tile heating them up and essentially warming up the entire shower stall. I'm sure you'd need a filter of some sort to keep hair and junk out of the pump, but other than that it would be a pretty simple system.

After the shower is done, the warmed tile would contribute to heating the house also. If this is undesireable, you could simply not use it in summer. The warmer shower stall would also allow you to use less hot water to feel just as warm.