- Inconsistent Temperatures: If some rooms are too hot while others are too cold, or if the furnace can't keep up with the thermostat settings, it may be a sign that the furnace can no longer distribute air properly.
- Unusual Noises: Older furnaces often start making strange noises near the end of their life cycle. Loud banging, popping, rattling, or squealing noises are not typical and should be investigated.
- Visible Signs of Rust or Corrosion: If you can see rust or other forms of deterioration on the furnace itself, especially around the burner or flue, the system might be compromised and could pose a safety risk.
- Yellow Burner Flame: The burner flame should be blue. A yellow or flickering flame indicates that the gas is not burning cleanly and could be producing carbon monoxide.
