The good news is that with Mojave’s new Home app you can turn lights on and off, lock and unlock doors, and do much more, right from your Mac, as long as the accessories are compatible with HomeKit, Apple’s framework for controlling smart devices around your house, and are connected to the same Wi-Fi network as your Mac.
For remote control over the Internet, you’ll need a device to act as a hub—an Apple TV, an iPad, or a HomePod speaker—to control devices over the Internet using a Mac (or iDevice).
Before you get too excited, if you’re not already using the Home app on an iDevice, you’ll need to start now because you can’t add new HomeKit accessories with the Mac Home app. Unless or until you add your HomeKit-enabled accessories to the Home app on an iPhone or iPad, you’re out of luck.
If you do have devices you’ve added to the Home app on your iDevice, you can use the Mojave Home app to turn them on or off. You can also create or edit scenes, which let you control multiple devices simultaneously, such as all the lights in the office.
You can also create or edit automations, which control devices or scenes based on the time of day or location of a device (usually an iPhone).