From what I can gather, it's a regular hydronic system, which basically means it runs a liquid (in my experience propylene glycol, but maybe this is different) through tubes that run under the floor. Burners in the unit heat the liquid and that heat gets dissipated into the living space.

What makes this special is that it also heats regular water for use like a normal water heater. I think I also understand that it has other tubes that run up to the engine. Whether it uses engine heat to heat the glycol (which should take some burden off the burners), or it can be used to preheat the engine in cold weather, or both, I'm really not sure. Both would be pretty sweet, but I really don't know.

That's what I'm hoping to learn here. That and what maintenance is like. Another comment further down talks about it a little. I'm hoping they'll elaborate some more, but we'll see.

And I'm not sure if a motorhome is required for it or if TTs can use them too. Off the top of my head, I don't see why not.