Our house faces north and the sun seldom hits the stairs in the winter. When it snows or sleets or anyone walks on snow before I have been able to get it cleaned off we had a pack of ice that seemed to last forever. It was very unsafe for anyone trying to use the stairs. A couple of years ago I bought two packs of the three treads and hooked them together and the stairs have been clear of ice and snow ever since. We were afraid that someone would get badly hurt on them. We have had many compliments from visitors and delivery men since then. It doesn't stay on all the time but comes on when the temp drops to freezing.