In-line water heaters.

[Tmall]

Originally Posted by fasternyou929

No, I don't think you do. You guys are talking about two different scenarios:

First time you turn on hot water after an extended period of non-use, you will get cold water until hot water reaches the faucet you've opened for both styles of water heater. Advantage: neither

If you have hot water at the faucet, turn it off momentarily,then turn it back on:

Inline heater - you will have a "section" of water that passes the instantaneous water heater while it's inactive, resulting in:
Hot Hot Hot Hot Cold Cold Cold Hot Hot Hot Hot.... in your hot water pipe.

Water tank - you would have a consistent stream of hot water in your hot water line and there wouldn't be any "surprise" coming your way in a few seconds.

Bingo, and that section doesn't turn cold, it was cold to begin with. It just hasn't been heated.

It's really not a huge issue, but some people don't like it. I used to turn the faucet on and off when I shaved, now I just pour the sink full of hot..