In a new project we are undertaking the customer has asked that a heating system be put in the the trough to prevent icing. The job location is in canada where the temperature routinely drops below -40 F. The trough being put up will be 6" painted steel. Basically I am looking for advice on a durable, low maintenance product. there is about a mile worth of trough on several buildings so I assume that heat cables are the way to go but I am open to options. thanx.