This warehouse initially had 250W SONs but over the years had started to replace them with expensive 250W metal halides in the hope that the lamp life may be extended. The result combination of the two lamp types gave Lux readings of 160Lux.
Sodium and metal halide lights typically give higher Lux level readings when compared with induction lamps of lesser wattages but the human eye tells the brain the light is brighter and clearer. This is because sodium and metal halide lamps give off much of their light in the yellow green spectrum of light where most photometry is weighted. Induction lamps however, produce most of their light in the bluish green region and so a lot if it isn’t detected by the meter. The naked eye detects in both regions which is why induction looks brighter but the meter reads lower.
LSLCo retrofitted the existing housings with 150W induction lamps. The pictures clearly show improved quality of light which in this case was also supported by the Lux meter which gave a reading of 230Lux.
In summary, the project delivered over 50% energy savings with a payback of around 3 years.