KNX: what and why
European open building automation standard. Wired bus, 500+ manufacturers of compatible equipment
What is KNX
KNX is an open international standard for building automation (EN 50090 / ISO/IEC 14543). It is a wired bus through which smart devices communicate: dimmers, switches, sensors, thermostats, blinds, air conditioners.
The standard is over 30 years old and is supported by more than 500 manufacturers (ABB, Schneider, Hager, Gira, Jung, Berker, MDT, Theben). Equipment from different brands is compatible with each other, providing freedom of choice.
When to choose KNX
KNX is the standard for apartments and houses from 100 m² where you need to control at least 10-15 lighting groups, blinds, climate. For a small studio with one lamp — it is excessive.
It fits well into renovation: KNX cables are laid together with power cables during the rough finishing stage. After finishing — panels, dimmers and sensors are installed.
For objects of 200+ m² — practically the de facto standard in the Hi-End segment in Europe. In Russia — the main choice among serious integrators.
How the KNX bus works
KNX cable is a green twisted pair (usually 2×2×0.8 mm). It is laid in a star or loop from the panel. Each line — up to 64 devices, a maximum of 15 lines in one zone via line couplers.
KNX devices receive power from the bus itself (24V DC). No separate power supplies are needed for each sensor. The bus load capacity is 640 mA per line.
Programming is done in ETS (Engineering Tool Software) — a development environment for KNX projects. The license costs ~€1000, but every certified KNX partner has one.
What KNX can do
Lighting control: dimming, scenes, presence sensors, astronomical timer (sunrise/sunset). Blind control: venetian blinds, roller blinds, pleated blinds, awnings. Climate control: radiators, underfloor heating, fan coil units, air conditioners.
Scenarios: Morning (blinds open to 30%, light 50%, underfloor heating in the bathroom turns on at 6:30). Cinema (lights go out, blinds close, projector turns on, climate control goes to comfort). Leaving home (everything turns off, security turns on, presence simulation).
Integration with other systems: via KNX gateways — with Lutron (RF), Crestron, audio-video, access control, fire alarm, weather stations, solar panels.
Certification
A certified KNX partner is an engineer trained by the KNX Association. There are two levels: KNX Partner (basic) and KNX Advanced (extended).
The certificate is renewed every 2 years. This ensures that your integrator is aware of the latest changes in the standard and new devices. Without a certificate — working with KNX is not recommended: too many nuances that do not forgive mistakes.