When a retailer, hotel operator, or facilities manager decides to retrofit existing lighting with LED, one problem consistently derails projects: conflicting photometric data from different labs, different test conditions, and different measurement standards. The incumbent supplier's data shows one number. The replacement LED supplier shows another. Nobody can agree on whether the retrofit will actually deliver the promised energy savings and maintained light levels.
YNDLUX solves this with a straightforward process: bring us your existing fixture, we test it and the replacement LED on the same goniophotometer, under the same conditions, in the same laboratory. One lab, one dataset, zero ambiguity.
The Problem With Standard Retrofit Comparisons
Retrofit projects typically fail to deliver their promised savings for one of three reasons:
- Mismatched beam angles: The replacement LED has a different beam spread. Light levels in the work zone drop even though total lumens are similar.
- Inconsistent test conditions: The existing fixture was tested at 25°C ambient, the new LED was tested at 35°C or under different drive conditions. The resulting lm/W figures are not directly comparable.
- Different photometric standards: European projects use LDT (EULUMDAT) format for DIALux and Relux simulations. If the replacement supplier only provides IES files measured to North American LM-63 standards, the optical data may not align with what European design software expects.
These discrepancies are not always deliberate. They arise from using different testing equipment, different labs, and different interpretations of IEC standards. But for a facilities manager who has committed to a specific lux level and energy target, the gap between expectation and reality is a serious problem.
The YNDLUX Same-Lab Methodology
Our approach is simple: before specifying a replacement LED, we test the existing fixture in our facility using an EVERFINE goniophotometer — the same instrument used to certify all YNDLUX products.
The process works as follows:
- You ship us your existing fixture (or a representative sample — typically 1–3 units is sufficient for a reliable baseline).
- We run a full goniophotometric test on the existing fixture: luminous flux (lm), luminous efficacy (lm/W), beam angle distribution, and we generate both IES and LDT (EULUMDAT) photometric files.
- We match to the correct YNDLUX replacement — selecting a model that replicates the beam angle distribution of the existing fixture as closely as possible, while delivering higher lm/W efficiency.
- We test the replacement YNDLUX fixture on the same goniophotometer under identical conditions. You receive side-by-side IES and LDT files for both fixtures.
- We provide a written comparison report showing the verified lm/W difference, lumen output, beam angle overlay, and calculated energy saving — all from the same instrument, same conditions, same lab.
Because both datasets come from the same EVERFINE goniophotometer under identical test conditions, there is no room for dispute. The data speaks for itself.
What the Test Report Includes
Every YNDLUX same-lab comparison report covers:
- Luminous efficacy (lm/W) — the fundamental energy efficiency metric, measured identically for both fixtures
- Total luminous flux (lm) — actual light output under controlled conditions
- Beam angle distribution — polar curve and candela distribution, confirming the replacement maintains the correct spread for the application
- Colour temperature (CCT) and Colour Rendering Index (CRI/Ra) — measured by integrating sphere, confirming visual quality is maintained or improved
- IES file (.ies) — compatible with North American and international lighting design software
- LDT file (.ldt, EULUMDAT format) — required for DIALux and Relux simulations used across Europe
- Calculated annual energy saving — based on verified wattage difference, not datasheet estimates
A Practical Example: Retail Track Light Retrofit
A retail client was running 50W halogen MR16 track spotlights across a 300 m² store — 60 fixtures operating 12 hours per day. They had received conflicting proposals: one LED supplier quoted 15W fixtures at "equivalent output", another quoted 20W at "brighter than halogen". Neither could produce comparable photometric data.
Using the same-lab methodology:
- Goniophotometer test of the existing 50W halogen: 820 lm, 16.4 lm/W, beam angle 38°
- YNDLUX selected replacement: 30W LED, 4,950 lm, 165 lm/W, beam angle 36° — measured on the same instrument
- Verified wattage reduction: 50W → 30W per fixture = 40% power reduction
- Annual energy saving for 60 fixtures at €0.19/kWh: approximately €1,000/year
- Both IES and LDT files delivered for DIALux verification before purchase commitment
The client approved the retrofit based on data, not promises. No disputes after installation.
Why Beam Angle Matching Matters as Much as Lm/W
A common mistake in LED retrofit projects is optimising only for lm/W while neglecting beam angle distribution. A 30° beam LED replacing a 38° halogen will produce noticeably darker edges in the lit zone — even if total lumens are identical or higher. In retail, this affects how merchandise looks on shelving and how customers perceive store brightness.
The goniophotometer candela distribution chart shows exactly how light is distributed across the full angular range. By overlaying the polar curves of the existing fixture and the YNDLUX replacement, we can confirm that the beam spread is matched before any product is ordered.
YNDLUX offers beam angle options from 15° (accent/narrow spot) to 60° (wide flood) across our magnetic DC48V and AC track ranges, with custom optics available for volume OEM projects.
Who This Service Is For
The same-lab retrofit methodology is designed for:
- Retail chains and shopping centres planning a multi-site LED retrofit programme
- Hotels and hospitality operators where consistent light quality across properties is critical
- Lighting designers and electrical contractors who need defensible photometric data to present to end clients
- Facility managers who have been burned by underperforming LED retrofits before and need verified data before committing budget
- OEM and distribution partners who want to offer clients a technically credible retrofit service
Getting Started
Send us your existing fixture — or the datasheet with the original photometric file if available — and describe your application (retail, warehouse, hospitality, office). We will confirm whether a same-lab comparison is the right approach and provide a timeline for the test report.
All photometric testing is conducted on EVERFINE goniophotometer equipment. IES and LDT (EULUMDAT) files are included as standard. Reports are provided in English; other languages available on request.
