Efficacy Guide for Commercial Lighting
lm/W benchmarks, DLC tiers and rebate implications.
1. Why it matters
Luminaire efficacy — delivered lumens per watt (lm/W) — is the number that drives energy cost, rebate eligibility and, increasingly, whether a product is even legal to sell. The trap is comparing the wrong efficacy: the bare LED chip, the light engine, and the finished luminaire are three different numbers, and only the last one reflects what you actually install.
2. Three efficacies, one that counts
| Level | What it excludes | Buyer relevance |
|---|---|---|
| LED chip (package) | Driver loss, optics, thermal derating | Marketing only — ignore |
| Light engine / module | Fixture optics and housing loss | Partial |
| Luminaire (LM-79) | Nothing — as installed | The number to compare |
3. Benchmarks and where to spend
Efficacy targets rise every year, but realistic 2020s luminaire efficacy for mainstream commercial LED sits in these bands. Chasing the very top costs money and often trades away CRI; aim at the band your energy code and rebate require, plus a margin.
- High bay / low bay: 140-180 lm/W achievable.
- Panels / troffers: 120-150 lm/W.
- Downlights: 90-120 lm/W (optics cost light).
- Outdoor / street: 130-170 lm/W.
4. Regulation and rebate gates
Efficacy is now a pass/fail gate, not just a cost lever. Rebate programmes (DLC in North America) and energy labels (EU ErP/energy classes) set minimum luminaire efficacy and quality thresholds by product type; a fixture below the line is ineligible for the rebate or, under some rules, cannot be placed on the market. Confirm the exact model appears on the qualified-products list, because the listing is model- and often SKU-specific — a similar model does not inherit it.
5. Checklist
- Compare luminaire (LM-79) lm/W, never chip lm/W
- Set the efficacy band your energy code + rebate require
- Confirm the exact model is on the DLC / energy-label list
- Balance efficacy against the CRI the space needs
- Check efficacy at the real drive current, not a low-current best case