Apple HomeKit devices can typically be controlled remotely using the Home app as long as there is an internet connection. However, if you are not connected to the internet, your ability to control those devices can be limited. Some HomeKit devices have built-in capability for local control, which means that if your HomeKit hub, such as an Apple TV, HomePod, or iPad, is connected to your local network, you may still be able to control devices via that local connection. This allows for basic operations directly through the Home app without requiring internet access. However, certain features that rely on cloud functionality or remote access would not be available without an internet connection. It is always a good idea to refer to the official Apple HomeKit webpage for detailed specifications and to ensure your devices support local control. This can help clarify any limitations or capabilities based on individual device models.