Things You Need:4 - AA batteries0-5 minutes of time Turn OFF the thermostat by pressing the Mode button until it shows off.Remove bottom Cover (it slides toward you).Remove 4 AA batteries and wait 20-30 seconds before putting in new AA batteries.Related Articles2GIG GC3 - How to Change BatteryGE Motion Detector - Low BatteryDoorlock - How to Change BatteriesDoorlock - How to Change BatteriesT6 Pro - How to Change Batteries