Anyone have this or something like it? It's job it to keep hot water at the tap rather than having to wait a few minutes for hot water. Seems like a pretty simple install.

They are quite common in houses with larger square footage due to longer hot water line runs.

I don't know much about this pump, but many systems are installed with the return loop.

Hmm. Very interesting. Though, I'm not exactly sure how this works.

Depending on how a house is plumbed, wouldn't this cause the cold water side of some faucets to become hot, then?

http://www.watts.com/pages/whatsnew/IHWRS.asp

So, the valve opens when the hot side cools to below 98 degrees. What isn't clear is if the pump shuts off if hot water isn't flowing (when the valves at the end of the loops aren't open).

So, I guess the cold side would be warm but would flush to cold pretty quickly.