How often should you service your furnace?
Once a year.
Best month: September (Northern Hemisphere)
How to do it
Book a heating tune-up before the cold season. A technician checks the burners, heat exchanger and safety controls.
Why it matters
A cracked heat exchanger can leak carbon monoxide. An annual check is how it gets caught.
Recommended interval: once a year, per ENERGY STAR (U.S. EPA).
General guidance for a typical home; the manufacturer's instructions come first.