Like a car, furnaces have lots of parts that can wear out over time. A furnace tune-up allows a professional to examine the inner workings of a furnace to ensure all of the important components are functioning correctly, and safely. Fixing any issue in the fall or early winter means you're less likely to have a breakdown when it's really cold outside, and when HVAC technicians are in high demand. To provide heat, a furnace has to burn fuel. Even a small problem in this combustion process can lead to harmful carbon monoxide levels or a dangerous gas leak. So, safety is another reason tune-ups are important. heating systems tune-ups can also extend the life of your equipment, due to improved efficiency and better air flow.