Here's a response from Kessil...................
There are many individuals, organizations, etc who try to use PAR readings for our lights.
We do not use PAR for measurements/comparison for the following reasons:
(1) PAR does not capture all the wavelengths needed for livestock growth, and coloration. PAR also does not distinguish the effectiveness of wavelengths. Higher PAR values does not necessarily translate to be more efficient. Eg. 50 PAR of green vs 50 PAR of blue. Theoretically, the blue is far more valuable but a PAR meter does not distinguish between the two. Worse still, it has less sensitivity in the blue/UV range.
(2) PAR also does not value wavelength combination. Kessil spent many years before launching any products to fine tune and test spectrum to balance the wavelength combinations. Kessil’s initial theories were based on an established successful practices and the most current biological research, all of which was verified independently. Through years of testing and experience, Kessil has refined lighting formulas that have proven to be effective.
Same as for CRI because it only tells how close it is visually comparing to natural light, but it does not tell us the efficiency of wavelengths and spectrum combinations.
For Kessil lights, they feature Kessil Logic, which maintains a very similar wavelength combination across different colors. This allows users to choose colors they like to see and not worry about balancing the wavelengths. It also maintains maximum output across each color, allowing the highest output possible.
Best,
Lai
510-620-5250