Thermostat shows temperature that is clearly inaccurate compared to other thermometers in the home.

Safety warning: Turn off power before removing thermostat if you need to access wiring or wall cavity.

• 1. Check location:
  • Ensure thermostat is not in direct sunlight, above electronics, or near supply registers.
• 2. Seal wall opening:
  • Remove thermostat and seal large wall openings with foam or putty to prevent drafts.
• 3. Adjust calibration:
  • Use the thermostat's temperature offset or calibration setting to correct minor differences (1–3°F).
• 4. Replace thermostat if error is large and persistent:
  • Significant sensor drift may require replacing the Lennox thermostat.