It is possible that your products won't automatically appear in the Home App from Apple at the end of the installation. This may be the case if, for example, the initial installation of the products was done using the account of a friend or family member or with an Android smartphone. Go to the Home + Control application settings and select ;Manage my home ;, select the room in which the thermostat is installed, select the thermostat and ; HomeKit & Siri ;. Follow the instructions in the application to configure the thermostat with HomeKit.