I had a floor heating cable go bad on a job, so I bought a little infared camera for my cell phone from FLIR. Just got it today and when I turned on my floor heat I was able to pick up the wires beneath the tile. It doesn't tell temperature, just a difference in temperature, so sometimes I had to put my hand in a pic to establish a "baseline". I took a pic of my patio door leaking a bit. There is actually only a 2? temperature difference between the wall and the hot spot. Hopefully I can create a hot spot in the floor cable with a megger and be able to see it. Maybe not real useful but another toy 
