The conventional method of measuring light transmission under a perpendicular angle of light incidence (0°) is intended for the comparison of regular (uncoated) glass.  However, in a greenhouse the incident angle of the sunlight is perpendicular less than 1% of the daytime hours.

To determine the real benefit of any high transmission glass under real greenhouse lighting conditions Dr. Peter van Nijnatten from TNO has developed a method for measuring light transmission under all angles of incidence.  This provides a much more accurate and realistic measurement of real improvement in light transmission of any AR coating.  This measurement shows GroGlass™ AR to increase the integral light transmission by 8%.