Thermostat shows room temperature much higher or lower than actual

Safety first: If relocating the thermostat involves wiring, isolate power first.

Steps:

• 1. Compare with reference: Place a reliable thermometer next to the thermostat and note the difference.
• 2. Adjust calibration: In the thermostat settings, use the 'Temperature offset' or 'Calibration' option to correct the reading by the measured difference.
• 3. Check location: Avoid mounting above radiators, near TVs, or in direct sunlight. If necessary, relocate the thermostat to an interior wall in the main living area.
• 4. Seal wall box: If cold draughts come through the cable hole, seal around the cable with non‑flammable filler to prevent cold air affecting the sensor.