hammersley, I install these quite often. Here in MN, tile gets COLD in the winter!
A couple things:
-These heating kits will not warm up a floor quickly. There is alot ot heat up, not only the tile, but also the mortar, and the floor underneath it. They cant take upto 48 hours to get to the set temp depending on circumstances. Usually, if you have it set for the ambiant room tempurature or just slightly higher, it should be the most cost effective.
-They also require a dedicated 20amp 110v or 220v circuit. I would recommend a 220 circuit, and this is because it is more efficiant. Make sure you have room in the panel and access to run the wire between the thermostat and the panel.
-As far as install, they are pretty self explanitory. But the main things you need to make sure of are these.
--DO NOT cross any of the wires, this will damage it.
--Make sure if this is a "permit pulling job" that you check with your local codes, some require that the heating wires are inspected before the flooring is poured/installed.
--The heating wire can not pass under cabinets or permenate fixtures.
-Get a programmable thermostat, it may cost more, but it will save you in the end. no reason to heat the floor at your desired temp while your at work.
-As far as covering the mat or heating wires, that is up to you. Some installers just install the sub flooring, then the wires, then tile. Others, use the wires, plastic meshing, self-level product, then tile. Personally, I like the later, gives you a flat floor to work with, and you dont have to worry about cutting the wires while installing the flooring.
Good luck on your install, and if you have any other questions, I will try to answer them the best I can, as quickly as I can!
-Matt