In the event of a power outage, your thermostat will stop working. However, the product is designed to work again as soon as power is restored, and return to the state it was in before the power outage. Please note that it may take several minutes for the thermostat to reconnect to the Internet and be accessible again via the app. If there is an Internet outage, your thermostat will continue to work locally and follow its programming. During the outage: - You cannot control your installation via the Home + Control app or change the settings. - You can however control and view the temperature directly on the thermostat. - The Apple Home app will continue to work as long as the local connection to the router is maintained. You will automatically regain all functions as soon as the Internet connection is restored. Please note that it may take a few minutes for the thermostat to reconnect.