Yep, Johan is right. My write up is here:
Bathroom Heated Tile Floor - JdFinley.com However; I haven't yet finished the wiring/powered it up. So, no actual experience to report.
I'm having to dig several months back into the grey matter but IIRC, the issues for me were...
1. Ceiling height. I don't have a lot and increasing the floor "thickness" to accommodate water lines was a problem. I thought about installing the lines under the floor (via the basement) but that was not going to be easy or quick.
2. I was worried about leaks over time (as Tango noted). Especially given my propensity to drill a hole or insert a screw before thinking.
3. .... something else... I can't remember what it was but I know there was another factor...
It seems to me that electric is used to 'heat the floor' whereas hydronic is used to 'heat the room'. Big difference. I think I would love a diesel/electric fired hydronic system cause it is a wonderful feeling heat (at least it is in a S&B home) but I just couldn't justify it in the bus.