Keep KNX responsible for the building controls it already handles well
A sound KNX installation already controls lighting, covers, climate or other building functions through a distributed wired bus. Home Assistant can add dashboards, cross-brand integrations and higher-level automations without moving every essential function into the Home Assistant server.
That boundary allows wall controls and core KNX logic to continue while the integration layer is being updated or serviced.
Start with the ETS project and group addresses
The current ETS project, keyring where secure KNX is used, group-address structure and device documentation are the foundation. Without them, the work begins as an audit rather than a straightforward integration.
Home Assistant connects through a local KNX/IP interface or router. It can receive live telegrams, control supported device types and expose selected Home Assistant states back to the KNX bus.
Bring only the useful KNX functions into Home Assistant
Expose the functions Home Assistant needs instead of importing the whole bus indiscriminately. Lighting states, temperatures, covers, selected scenes and occupancy may be useful. Diagnostic or low-level addresses may belong only in the KNX commissioning record.
Naming and state addresses matter. A command-only group address can produce an attractive control that does not reliably show what the building is doing.
Secure the KNX/IP connection and keep its details with the project
Record whether the connection uses KNX/IP tunnelling or routing, its network path and any KNX Secure material. Keep ETS and keyring files under owner-controlled custody with appropriate protection.
Commission the system by comparing wall control, bus telegrams and Home Assistant state. The handover states which automations live on KNX and which depend on Home Assistant.
Primary references
Quick answers to common questions.
01Can Home Assistant replace KNX?+
It can control and automate KNX through an IP interface, but a sound design normally keeps essential field control on KNX and uses Home Assistant as an integration layer.
02What is needed to connect KNX to Home Assistant?+
A local KNX/IP interface or router plus the relevant group-address and project information. Secure installations also need the appropriate key material.
03Does KNX work locally with Home Assistant?+
Yes. The official integration communicates locally over KNX/IP and receives bus telegrams as they occur.
04Can Home Assistant send states back to KNX?+
The integration can expose selected entity states and send or receive supported KNX group communication when configured deliberately.