So my water heater took a shit
 

And I bought one of those tankless things that are about a foot and a half by a foot and a half. It took 2 50 amp breakers but it is sweet. I ran the hot water in all faucets for over 3 hours and it never started to cool.

Our town buys cheap electricity from Niagara Mohawk so electricity is cheap.

What's it do? Heat coils & run water thru so that it's always the same temp when it comes out?

Restaurants have something like that - called a "quick return" or something - we had one until it spewed water all over the attic of the Pool House :D

Yeah, a friend has a "quick return" in his Bed and Breakfast.... it rules

Yeah, something like that but I really don't see any coils. I see two quart size containers. This one has something that senses a leak and shuts off the water to it. That must be a common problem if they build that in to the unit.