[mrclark411]

Just moved into our "forever" home and our setup is very similar to isbjorn16's (7 in the family, HPWH "80G", but I have an 8" PowerPipe from these folks: http://renewability.com/#learn-more. (It's a monster - plumber wanted to give me a clean out at the bottom - but that meant some jackhammering to set it low enough.)

So far so good - we do a bunch of baths/showers at bed time and no one runs out of hot water. Also - I'll add that we accidentally had the plumber remove all the low flow "plugs" from the showers so there's a lot of water flowing.

The pipe is pretty fun - not only is it fun to look at - but when someone is taking a shower it's fun to feel the heat at the top of the pipe and as you move down the pipe it gets colder until it reaches the temp of the cold water coming into the house.

Since it was new construction - we'll never know how much of a different the drainwater heat recovery pipe is making - but it is definitely doing work.

I can imagine these pipes becoming more popular (though rising prices will kill off any efficiencies real fast). Maybe code?