Photometric assessment of warm and cool white LED bulbs

The usage of white LED has increased at a rapid rate in India for residential applications because of its various advantageous properties such as energy efficiency, low power consumption, high brightness, reliability and long lifetime compared to other conventional lamps. In this paper, photometric parameters such as CCT, CRI and luminous flux for warm white and cool white LEDs are explored. Integrating sphere was used for examining the LEDs for their performance characteristics in terms of photometric parameters. The results show that warm white LEDs have a relatively low correlated colour temperature, colour rendering index and luminous flux (lumens) compared to cool white LED bulbs. With an increase in power consumption, the efficacy, lumen output and power factor increase. In terms of high brightness, cool white LED bulbs are brighter than warm white LED bulbs, whereas in terms of power quality issues such as harmonics and power consumption, warm white LEDs are better than cool white LEDs.