Furnace (Gas): lifespan, maintenance and replacement

Typical lifespan: 15–25 years (about 18 years).

Maintenance schedule

• Replace air filter — Every 1–3 months
• Professional inspection and tune-up — Annually (fall)
• Check thermostat calibration — Annually
• Inspect flue and venting — Annually
• Clean blower assembly — Annually

Signs it needs replacing

• Yellow burner flame (should be blue)
• Frequent cycling on and off
• Cold spots in the house
• Increased dust or dry air
• Carbon monoxide alarm: leave immediately and call emergency services from outside
• Rising heating bills

Tips

Carbon monoxide is odorless and cannot be diagnosed by flame color. For a CO alarm, leave immediately and call emergency services from outside. For a gas smell, leave without operating switches and call the gas utility from a safe place. Have combustion or venting concerns professionally inspected.