Thermostat shows humidity reading that is clearly inaccurate compared to a known-good hygrometer.

Safety warning: Turn off power before removing thermostat if wall work is needed.

• 1. Compare readings in stable conditions:
  • Check humidity when doors/windows are closed and HVAC is off.
• 2. Relocate thermostat if in poor location:
  • Avoid kitchens, bathrooms, or near humidifiers.
• 3. Seal wall opening:
  • Seal large wall gaps behind thermostat to prevent moisture-laden air from wall cavities affecting readings.
• 4. Replace thermostat if humidity sensor is far out of range:
  • Internal humidity sensors are not typically serviceable.