HomeKit integration is available as a simple update of the mobile Ikea app for iPhone.
The TRÅDFRI lights are popular for their relatively low cost. However, before the HomeKit support was added reviews were mixed. The setup process is very easy: after updating the app, it’ll generate a unique code that will allow you to add it to your HomeKit setup.
This lets you take advantage of everything HomeKit has to offer such as scheduling, automation, triggers and integration with all other HomeKit accessories, even Siri voice control.
Currently, HomeKit support is limited purely to the lights.
Dimmers, switches and other accessories are currently not supported. The TRÅDFRI lights are comparable to the Philips Hue line, but are a bit cheaper to expand.
Compared to Ikea, Philips recently added HomeKit support to their Hue line of dimmers and switches. To get started, you can pickup a gateway and two bulb pack for under a $100 on Amazon, or less if you are near an Ikea store.