What is LonWorks?
LonWorks is a building automation networking protocol that was widely adopted in commercial buildings during the 1990s and early 2000s.
It was commonly used to control HVAC systems, plant equipment, lighting, and other building services before modern open protocols such as BACnet became dominant.
What LonWorks was used for
- HVAC and plant control
- Terminal unit and controller networks
- Lighting and shading systems
- Energy monitoring
- Early Smart Building automation
How LonWorks works
LonWorks uses a decentralised architecture where intelligent devices communicate peer-to-peer across a network using a proprietary protocol.
Devices were programmed using specialised tools and often relied on manufacturer-specific implementations, which limited interoperability over time.
LonWorks vs modern BMS protocols
While LonWorks was innovative for its time, it has largely been replaced by more open, flexible standards.
- LonWorks – legacy, proprietary tooling, limited openness
- BACnet – open standard, widely adopted in modern BMS
- KNX – decentralised control, strong in lighting and room automation
- Modbus – simple, reliable field protocol for plant and meters
Where LonWorks is still found
Although no longer the preferred choice for new installations, LonWorks is still present in many operational buildings.
- Older commercial office buildings
- Hospitals and healthcare estates
- Education campuses
- Large estates with long asset lifecycles
Integrating LonWorks today
Modern Smart Buildings often integrate legacy LonWorks systems into newer platforms rather than replacing them immediately.
Integration is commonly achieved using gateways into platforms such as Tridium Niagara or modern BMS front ends.
Roles that still work with LonWorks
- Legacy BMS Engineers
- BMS Service Engineers
- System Integrators
- BMS Project Managers
Why LonWorks still matters
Understanding LonWorks is essential for maintaining, upgrading, and migrating legacy BMS estates. Many live buildings still depend on it for core control functionality.
For engineers and employers alike, LonWorks knowledge often signals deep, practical experience rather than greenfield-only exposure.