Underfloor heating mat in upstairs bathrooms

Upstairs we have got no heating system.  The mechanical ventilation heat recovery system will preheat the fresh air so this will provide some sort of heat, and, well, heat rises!  As we have a tiled floor in the bathrooms we were concerned about the floor feeling cold underfoot and so we have opted to install an electric mat with a rather sophisticated control and monitoring thermostat, so we can see how much energy it is using and try and reduce this as much as possible by getting optimum performance out of the mat.

The heating wires come contained within a fiberglass mesh which makes it incredibly easy to lay.  You can cut the mat (but obviously not the wires) to flip and rotate it to get the right shape.

The mat rolled out in the family bathroom.  This will need to be secured down before tiling but we jut want to lay it out for now to see where to put the thermostat back box, we will then roll it up again until we are ready to tile.