Breaking Down LED Output Data - Total Lumens vs Delivered Lumens

14 Aug 15

Claims, claims and more claims… LED lighting manufacturers and suppliers offer tough competition about which LED products have the best performance or deliver the greatest efficacy. It can be difficult to cut through the numbers and jargon used in the industry for a real and true comparison of LED lamps and luminaires. Previously, industry professionals compared lamps and luminaires based on their wattage, it had its pitfalls, but was used as a rule of thumb. With the industry disruption brought about by LED, professionals can no longer rely on wattage and now compare performance based on lumens. But not all lumens are the same – great care must be taken to ensure apples are being compared with apples and not oranges.

Manufacturers and suppliers of lamps and luminaires publish their lumen output figures that are used for performance comparison. However, there are two types of lumen output figures: Delivered Lumens and Total Lumens. One lumen type is useful, while the other is a theoretical figure that doesn’t accurately reflect real performance. So which lumen figure is the best to compare performance?

Total Lumens represents the total amount of light emitted from the LED module itself. This figure does not take into account any light losses from filtering light through the LED lens or luminaire cover lens, losses from distribution of light from an internal reflector or luminaire positioning for example. It is in reality only a theoretical number with no bearing on real performance.

Delivered Lumens does represent real exit lumens that are projected from a lamp or luminaire. These are the actual working lumens projected toward the horizontal or vertical plane. They are a practical measure used to state real performance.

In conclusion, delivered lumens is the metric that indicates real performance of a luminaire and should be used for comparison. Sometimes this is also called real lumens or exit lumens.


All EYE Lighting’s product information contains Delivered Lumen data to best enable real performance comparison.