IDG’s Fred O’Connor:

People looking to control their HomeKit-compatible devices when they’re away from home will need an Apple TV to complete those tasks, Apple confirmed in a support page for its smart home platform.

…

As long as the same Apple ID is used to log in to the iOS device and Apple TV, people can speak commands to Siri to control HomeKit-compatible products.

HomeKit requires at least a third generation AppleTV which is, of course, the only AppleTV Apple currently sells. For at least the next six days.