Your products may not automatically appear in the Apple Home app after setup is complete. This may be the case if, for example, the initial setup of the products was done using a friend or family member’s account or with an Android smartphone. Go to the Home + Control app settings and select “Manage My Home,” select the room where the thermostat is installed, select the thermostat, and “HomeKit & Siri.” Follow the instructions in the app to set up the thermostat with HomeKit.