Thermostat shows very high or very low indoor humidity readings that do not match actual conditions.

Safety first: No high-voltage work is required.

• Step 1 – Verify with hygrometer: Place a standalone hygrometer near the thermostat and compare humidity readings.
• Step 2 – Clean sensor vents: Use a soft brush or compressed air to gently clean the small vents on the thermostat housing.
• Step 3 – Avoid moisture sources: Ensure the thermostat is not located near bathrooms, kitchens, or humidifiers where steam can affect readings.
• Step 4 – Adjust calibration: If the thermostat allows humidity offset, adjust it to match the reference hygrometer.
• Step 5 – Replace thermostat: If readings remain inaccurate, the internal humidity sensor is likely failed.