Navigating the Choice Between DALI-2 and DALI+ in the Era of Sustainable Smart Buildings
The landscape of architectural lighting has undergone a radical transformation. No longer is lighting merely a utility for illumination; it has become the “nervous system” of the modern smart building. As of 2026, the industry has reached a pivotal juncture in how these systems are controlled, primarily through the evolution of protocols such as IEC 62386, more commonly known as DALI.
When choosing a smart lighting control system today, the central debate lies between the established reliability of DALI-2 (wired) and the agile flexibility of DALI+ (wireless). Making the right choice requires an understanding of how these technologies intersect with global standards, sustainability targets, and the long-term operational goals of a commercial space.
The foundation: Understanding the standards
At the heart of any professional lighting project is the DALI standard. Before the widespread adoption of DALI-2, the original DALI (Digital Addressable Lighting Interface) suffered from interoperability issues where devices from different manufacturers often failed to communicate effectively. Self-certification didn’t work, so validation of compliance and interoperability were only achieved through DALI-2 and third-party testing.
The DALI-2 revolution
DALI-2, launched by the Digital Illumination Interface Alliance (DiiA), introduced a rigorous certification process. This ensures that a sensor from Manufacturer A will work seamlessly with a driver from Manufacturer B and a controller from Manufacturer C.
- Part 101/102/103: These sections define the system, control gear (drivers), and control devices (sensors and switches), ensuring a unified digital language.
- Interoperability: This is the most critical decision-making factor. Choosing a DALI-2 system protects against vendor lock-in, allowing building owners to source the best-in-class components throughout the building’s lifecycle.
The arrival of DALI+
DALI+ represents the logical evolution of the standard into the wireless and IP-based domain. Based on IEC 62386 Part 104, DALI+ allows the same DALI commands — including sophisticated dimming curves, diagnostic data, and grouping logic — to be carried over wireless carriers like Thread or Ethernet.
The decision matrix: Wired (DALI-2) vs. wireless (DALI+)
When deciding between these two, the choice often hinges on the specific constraints of the building and the desired level of future-proofing.
DALI-2: The wired gold standard
DALI-2 remains the preferred choice for new-build projects where the ceiling infrastructure is accessible.
- Physical robustness: Wired systems are immune to RF (radio frequency) interference. In environments with a high density of wireless traffic or thick structural shielding (such as medical facilities or high-security government buildings), the physical two-wire bus offers unparalleled stability.
- Power over bus: A significant advantage of wired DALI-2 is that the control bus can often provide power to control devices (sensors and switches), eliminating the need for batteries or separate power supplies.
DALI+: The wireless frontier
DALI+ is transformative for retrofits and flexible workspaces.
- Ease of installation: By removing the need for a dedicated control cable, DALI+ significantly reduces labour costs and material usage.
- Scalability: In a DALI+ over Thread mesh network, every luminaire acts as a node, strengthening the network as more devices are added. This is ideal for Cat B office fit-outs where layouts change frequently.
The role of sustainability in the decision
In 2026, sustainability is no longer a “nice-to-have” feature; it is a regulatory and ethical mandate. Lighting controls are the primary driver for achieving BREEAM (UK), NABERS, and LEED (International) certifications.
Energy Performance of Buildings Directive (EPBD)
Recent updates to the EPBD mandate that by May 2026, non-residential buildings must be capable of continuous monitoring and logging of energy use. Both DALI-2 and DALI+ systems, when equipped with D4i or compliant DALI drivers, support:
- Real-time energy monitoring (Part 252): Accurate reporting of active energy and power consumption.
- Diagnostics and maintenance (Part 253): Identifying lamp failures or driver issues before they become critical, reducing site visits and associated carbon emissions.
- Luminaire data (Part 251): Storing asset information (wattage, colour temperature, manufacture date) directly in the driver to facilitate a circular economy.
Reducing material footprint
Choosing DALI+ wireless directly impacts the embodied carbon of a building. By eliminating kilometres of copper cabling and plastic conduit required for a wired bus, the cradle-to-gate environmental impact of the lighting installation is drastically reduced.
Key decision criteria: A comparison table
| Feature | DALI-2 (Wired) | DALI+ (Wireless/IP) |
|---|---|---|
| Physical medium | 2-core cable (DALI bus) | Wireless (Thread) or IP |
| Best for | New builds, high-security sites | Retrofits, flexible/agile offices |
| Installation | Higher labour, more copper | Lower labour, less cabling |
| Interoperability | High (via DALI-2 certification) | High (via DALI+ certification) |
| Maintenance | Low (wired reliability) | Low (predictive via IP data) |
| Cybersecurity | Physical security of the bus | Robust (Thread/IP encryption) |
Network security and IP integration
As lighting becomes part of the IT infrastructure, cybersecurity is a paramount concern.
- DALI-2: Inherently air-gapped from the wider world, providing security through isolation.
- DALI+: Leverages the security protocols of its carrier. For example, DALI+ over Thread uses AES-128 encryption. This enables lighting to reside safely on a building’s IP network and share data with HVAC and security systems for a truly integrated smart building.
Circularity and lifecycle
The standardisation aspect of IEC 62386 is perhaps its greatest contribution to sustainability. In a proprietary system, if a manufacturer goes out of business or discontinues a product line, the entire system may need to be replaced.
With DALI-2 and DALI+, the building owner invests in an open ecosystem. If a DALI+ sensor fails ten years from now, it can be replaced with a certified sensor from another manufacturer. This prevents premature obsolescence and ensures the building remains functional for decades, significantly reducing electronic waste.
Conclusion: Making the choice
The decision between DALI-2 and DALI+ is rarely an either/or scenario in 2026. Most modern large-scale developments utilise a hybrid approach:
- DALI-2 for core infrastructure and critical areas where wiring is easily integrated.
- DALI+ for flexible open-plan areas, meeting rooms, and heritage retrofits where pulling new cables is prohibited or cost-prohibitive.
Ultimately, the key is to specify certified products. By adhering to the IEC 62386 standard, you ensure the system is not only smart, but also sustainable, secure, and interoperable. This strategic alignment with international standards safeguards the building’s value and contributes to the broader goal of a net-zero built environment.
Recommendations for the specifier
- Audit the building type: For listed heritage buildings, DALI+ is almost certainly the better choice. For new-build high-rises, a wired DALI-2 backbone with wireless clusters is the gold standard.
- Focus on data: Ensure all drivers are DALI Data compliant to meet 2026 EPBD energy logging requirements.
- Verify certification: Always check the DALI Alliance database to confirm the DALI-2 or DALI+ logo is officially granted, not merely “compatible.”
Author: Stewart Langdown FSLL (Fellow of the Society of Light & Lighting)