TOP EFFICACY PERFORMERS: THE QUALITY TRADEOFFS IN LED LUMINAIRES

In 2017, several luminaires in the LED Lighting Facts database claimed efficacies between 144 and 210 lm/W. Samples were procured for testing and visual evaluation. Seven luminaire models were ordered, all but one having directly visible LED packages. They underwent photometric testing for comparison to manufacturer-claimed values. All but one performed between 150 and 200 lm/W. Pairs of each type were mocked-up in a lighting laboratory. Direct measurements of the exposed LEDs revealed luminances ranging from 626.000 to 1.150.000 cd/m, with one employing diffusers at 41.500 cd/m. 23 lighting-experienced observers evaluated the luminaires, providing comments and an overall perceived dollar value. Only two luminaires received positive ratings of visual comfort and overall quality, those with either diffusers or reflector optics to reduce direct view of bare LEDs. The three rated highest for monetary value received positive comments in light distribu tion, colour, and visual comfort; the three lowest rated received the most negative glare comments. The highest rated luminaire exhibited the lowest efficacy of 136 lm/W, suggesting that visual comfort, light distribution, and colour quality may be of equal or greater importance to an installation.