If your furnace has any problems, it doesn’t take a scholar to know that when it snows, the furnace is going to break down. It doesn’t need to be snowing to make the furnace suddenly quit working. Any kind of inclement weather, including extreme cold, will give the furnace the impetus it needs to finally quit. Maybe you’ve never experienced this, but I have. Twice in the last fifteen years, my furnace has died during the worst weather in the season. The HVAC technician told me the reason was because the furnace is working hard to keep up with the weather. It is trying to fight off the cold so you can stay warm. Any components that aren’t perfect are getting added strain and are bound to break at that time. You can explain that it is an overworking furnace, or Murphy’s law, or that my furnace is taking this chance to get back at me for now being more vigilant. Whatever you say, it still doesn’t make it easier to take when your furnace breaks down during a period of really bad weather. This has happened to me twice in the last fifteen years. Within a year of buying my home, I had to have the HVAC system replaced. Fifteen years later, during the blizzard of a lifetime, my furnace, which was fifteen years old, died. When you’re left out in the cold for almost a week because of no furnace, it doesn’t make for a good week.