Is heat tape or Roof De-Icing Cable good for the roof?
Providing the constructed building was properly insulated to code and spec, adding environmental impact, nothing beats a ladder and shovel to clear snow. Cleared gutters and eavestroughing after the leaves drop every fall and if ice damming does occur, purchase de,ice pucks from a hardware and supply center. Most chains carry it. Simply toss a puck every few feet apart up onto the roof. They de ice and clear out eaves. Ice dams also are pretty good indicaters of an improperly vapor barriered or insulated roof. DO NOT RUN HEAT TAPES! Thats asking for trouble. Jon, AB, CAN
If you're having major ice dam problems, the solution is to beef up your attic's insulation, especially at the edges. Ice dams are caused by heat rising through your attic due to insufficient insulation, where it melts the snow which re-freezes once it hits the cold gutter. If you're preparing to spend money to fix the problem, I suggest spending it on increased attic insulation, which is more likely to actually fix the problem and will also make your house more comfortable.
Far better to both insulate & ventilate the attic better and use "Ice & Water Shield" (a thick, flexible, adhesive underlayer) rather than felt-paper for at least 8-12 feet up from the edge of the roof.
Heat cables are better than nothing, but they are a poor "solution" at best - expensive to operate and not really solving the underlying problem.