It was so cold here saturday that my oil lines froze! First time in 10 years that has happened. Woke up Sunday morning to a 50 degree house. Panic ensued until I got hold of the oil company who was out in an hour and diagnosed the problem. They torched the lines and the furnace fired right up. Now that I've experienced that, I know what to look for. The lines were insulated, but now they are DOUBLE insulated , also there is an electric blanket at the ready should this ever happen again. I hate winter!