thank you brad that looks very neat work .
what boiler are you using to heat the driveway
i will ask at work to see if there is something you can use to do what you want to check the temps .
this type of system has bin used in Europe for a long time to melt snow in intersection's and walkways .
we have some walkways in front of some buildings here that have it and if i have to redo my driveway i will put it in
i put in 4200 ft of 1" pipe in the ground for a freezer warehouse under the concrete to keep the cold from freezing the ground and lifting the building