Definition
DALI and TRIAC represent the two fundamentally different approaches to LED dimming: digital addressable control vs analog phase-cut power reduction. DALI (Digital Addressable Lighting Interface, IEC 62386) sends digital commands over a dedicated 2-wire bus — each luminaire has a unique address, receives precise digital dimming instructions, and reports its status back to the controller. TRIAC dimming physically chops the AC voltage waveform (phase-cut), reducing the power delivered to the driver — it's a 'dumb' power reduction that the LED driver must interpret. DALI is the modern, feature-rich protocol. TRIAC is the legacy, retrofit-friendly approach. The choice depends entirely on project scale and whether new control wiring is possible.
Key Data
| Parameter | Value / Explanation |
|---|---|
| Communication | DALI: digital two-way | TRIAC: analog one-way (power cut only) |
| Addressability | DALI: 64-128 individual addresses per bus | TRIAC: one dimmer controls all fixtures on circuit |
| Wiring | DALI: 2 additional bus wires (polarity-free) | TRIAC: uses existing 2-wire (no new wiring) |
| Feedback | DALI: reports lamp failure, energy, runtime | TRIAC: none — no feedback |
| Cost per fixture | DALI: $15-40 premium | TRIAC: $2-5 premium | DALI 3-8× more expensive upfront |
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Application Guide
New office (200+ fixtures)
DALI-2/D4i — individual control, energy reporting, workspace flexibility
DALI pays back through energy savings and reduced re-commissioning costs
Residential retrofit (8 fixtures)
TRIAC — uses existing 2-wire wiring, simple wall dimmer
DALI is massive overkill for small residential projects
Hotel guest room
TRIAC or wireless (BLE Mesh) — simple bedside dimming
Individual addressability not needed in single-room context
Conclusion & Procurement Recommendation
DALI for commercial projects over 50 fixtures, new construction, or anywhere energy monitoring and individual control are required. TRIAC for retrofit projects where running new control wires is impractical, or for projects under 20 fixtures. The cost crossover point is around 30-50 fixtures — below this, TRIAC's simplicity wins; above this, DALI's features and operational savings justify the premium.