At the moment the roof de-ices itself with the wasted heat, then the snow above justs skids off! The movement is towards insulation and power saving as a result. They might be useful on fragile roofs which can't take the weight of much snow, such as conservatories. A blanket of snow on a roof is seen as a good sign!

We have more of a problem with freezing temperatures at the moment. We are all together in Yorkshire at the moment, but Ruth and i are heading off in our opposite directions in a couple of hours. I'm heading to no more than -4C; Ruth's home area had -19C last night!

Andrea