I know it has been over a month since drkatiern originaly posted this but, since it has been resurected I thought I would post my $.02 worth. When we bought our current house I noted that there were ice melt cables on the roof and in the gutters. being new to the house and having several other more pressing tasks to take care of I gave them no thought. No thought untill we got our first electric bill for over $300.00 (normal for us was in the $60.00 range)I found out that the cables were still plugged in in the middle of the summer (no thermostat on them). My first thought was to entirely remove them , but figuring they were up there for a reason I figured I ought to investigate a little further. Up into the attic I went. what I found had me completly rethinking my plans for the summers projects. While there were perforated aluminum soffits, there were no vents in the original plywood soffits. also on the ridge there was a ridge vent but the opening was never cut in. They were put up there as a ridge cap only. so, couple the no ventilation with 4" of insulation and you could see the project forming rather quickly. After talking with some of the neighbors I found that they were having severe Ice damming issues to the point where one side of the roof had to be replaced due to the damage to the sheathing. Since fixing the vent and insulation problems I now have no Ice dams at all and very little ice buildup in the gutters each winter. So, My advixce is to look for and fix the root cause of the problem and not a bandaid fix