How to use roof & gutter heat cables
I have heat cables on my roof & in my gutters and downspouts. When my roof starts getting snow on it, I do not turn on the heat cables (I have an inside electric switch) because I never know if the snow will continue and I am trying to use the cables efficiently (cut down on my electric bill!) Given the winter we have had thus far coupled with the above philosophy, I now have heavy ice build up in the gutters and plenty of icicles. I just do not know how to use these cables!
Should they be kept on through the night when temperatures will be declining?
Should they be on only at certain temperatures?
How can I stay ahead of the game?
I would appreciate any advice or one's own experiences.