Choosing the right dimming technology is one of the most impactful decisions in a lighting design project. The two most common options in professional KNX installations are phase-cut dimming and DALI-2. Here is how they compare.
Phase-Cut Dimming (Leading Edge / Trailing Edge)
Phase-cut dimmers work by chopping part of the AC sine wave to reduce the power delivered to the lamp. They are simple, cost-effective, and widely compatible with retrofit LED bulbs.
Pros: Lower cost per channel, simple wiring, works with standard LED bulbs.
Cons: Can cause flicker at low dim levels, minimum load requirements, limited to one circuit per KNX dimmer channel.
DALI-2 (Digital Addressable Lighting Interface)
DALI is a protocol specifically designed for digital lighting control. A DALI gateway bridges the KNX bus with a dedicated DALI bus. Each LED driver on the DALI bus has its own unique address and can be controlled individually.
Pros: Smooth, flicker-free 0.1%–100% dimming; individual addressing of each fixture; tunable white and RGBW color control; two-way feedback (the driver reports its status back to ETS).
Cons: Higher upfront cost; requires DALI-compatible LED drivers; more complex commissioning.
Our Recommendation
Use phase-cut dimming for residential retrofits with standard LED bulbs where budget is a priority. Choose DALI-2 for architectural spaces, commercial projects, or anywhere you need smooth, high-quality dimming, tunable white, or color control.
