BACnet vs Modbus vs LonWorks
A clear guide to pick the right protocol for building and industrial automation.

In automation, the communication protocol defines how devices exchange data. The most common options are BACnet, Modbus and LonWorks. Each has different focus, cost and interoperability.

Quick overview

  • BACnet: building automation, open standard.
  • Modbus: industrial automation, simple and robust.
  • LonWorks: proprietary and declining in new projects.

BACnet

Designed for building automation with strong multi-vendor interoperability. Common in HVAC, monitoring and building management systems.

  • Media: BACnet/IP, MS/TP (RS-485).
  • Pros: open standard, strong integration.
  • Cons: more complex initial setup.

Modbus

Widely used in industry due to simplicity. Great for register-based data and basic control.

  • Media: Modbus TCP/IP, Modbus RTU/ASCII.
  • Pros: simple, low cost, widely supported.
  • Cons: limited advanced features and security.

LonWorks

A proprietary protocol with historical adoption in building and residential automation. It is less common in new deployments.

  • Media: TP/FT, PowerLine, RF depending on implementation.
  • Pros: legacy ecosystem in some markets.
  • Cons: higher cost, vendor lock-in, declining support.

Direct comparison

  • Interoperability: BACnet > Modbus > LonWorks
  • Focus: BACnet (buildings), Modbus (industry), LonWorks (legacy)
  • Cost: Modbus is typically the lowest
  • Future: BACnet and Modbus remain strong

When to use each

  • BACnet: multi-vendor building integrations.
  • Modbus: simple control and industrial monitoring.
  • LonWorks: existing legacy systems.

Conclusion

There is no universal best protocol. BACnet is a safe choice for modern buildings, Modbus is efficient for industrial needs, and LonWorks is best kept for legacy environments.