KNX : Definition

16 November 2023
3 min

What is the KNX Protocol

The KNX protocol has become an international standard adopted by many device manufacturers in the building automation and BMS sectors.

This protocol was created in 1990 by the KNX association to replace the former EIB, EHS, and Bâtibus standards and establish a new functional standard compatible with a number of manufacturers in the building automation sector.

KNX is an open-source standard available at the global level. This ensures that all components and functions of a building automation system are able to communicate clearly, instantaneously, and remotely.

The KNX protocol is designed to manage controller data using a single language, which is a vital design characteristic when working with multiple systems and installations in a building that relies on different coding languages.

How does the technology work?

The KNX bus is a wired protocol, however, all connected devices remain independent of any central server which makes the KNX protocol a decentralised system. 

This technology has various functions depending on the scope of the application.

In the case of the building automation of a private residence, the technology functions essentially as a fieldbus to connect the various components of an IT system. This ensures the various devices set up in a house or apartment can communicate with each other.

In a professional use case for a company, school, hospital, shopping centre, or industrial site, for example, this incredibly versatile solution can be implemented as a fieldbus or scaled up to become the “backbone” and core network for the site as a whole. 

Use cases: a solution for every building type

The KNX protocol allows a residential, commercial, or industrial building’s systems to communicate effectively with all relevant sensors/actuators along with their controllers in order to automate the building’s many functions such as heating, ventilation, air conditioning, water heating, lighting, safety, or energy management.

Furthermore, this technology can be retrofitted in older constructions as well as installed in new ones, which means it is compatible with all types of buildings and exterior spaces.

Advantages and disadvantages of the KNX protocol

As with any IT solution, the KNX protocol has many advantages, but there are disadvantages to take into consideration.


First, let’s cover the many advantages of the KNX system:

The KNX protocol provides a decentralised controller solution for all building equipment, that is to say without needing a central server.

By retrofitting older buildings, this easily implemented technology can modernize your entire site.

KNX building automation solutions are designed with growth in mind, allowing for the installation of additional controllers, for example. 

Being an open-source standard, this protocol has been adopted by many device manufacturers. As a result, users can benefit from a wide range of products with more or less guaranteed long-term compatibility.

The centralised management features of KNX technology are particularly useful when it comes to implementing energy optimisation strategies.  In other words, the KNX system will transform your site into a smart building.

Some relevant examples: dedicated presence detectors turn off building lights when there are no people present.  Blinds open and close automatically based on daylight hours in order to capitalise on sunlight and heat. Heating solutions switch on an hour before the user is scheduled to be present.


It is important that potential customers understand the potential disadvantages of these solutions as well.

For professional users, the main disadvantage of this technology is access restriction, as KNX systems can be vulnerable to cyber-attacks from outside the network. For this reason, it is vital to implement safety measures to manage hacking risks.

Another important feature to mention is that KNX is a wired solution which means it is more complex and costly to install compared to wireless solutions.

When it comes to domestic building automation, users must consider that KNX-compatible devices are expensive to purchase and install. Installation and maintenance of these devices can only be performed by a certified KNX professional. 


The KNX protocol is a top choice for BMS and building automation professionals as it ensures the various devices and controllers across your site remain interoperable with guaranteed long-term compatibility.

KNX is a game-changer for building system management. By providing access to hundreds of compatible devices that can be controlled remotely, users can easily and efficiently automate their building systems. The recent work aligning the KNX protocol with BACnet in order to establish a European building standard is proof that KNX is the foremost building automation solution that can ensure the interoperability of all connected devices. This standard allows users to break free of proprietary protocols that lockout non-proprietary components and make it difficult to optimise these building installations. Here at Wattsense, we share these values and work hard to establish KNX as the gold standard for building automation.