Luminous flux is key
The luminous efficacy of traditional light sources like incandescent bulbs is approximately 11-12 l/W. In other words, to truly replace a 40W incandescent light bulb, the luminous flux ought to reach at least 450lm.According to the comparative survey conducted by LEDinside, some vendors’ LED light bulbs indeed reach 450lm, but some vendors’ regrettably do not. For European and American lighting manufacturers like Philips and GE, Philips’ 8W Master LEDbulb and GE’s 8W Model No. 62180 LED bulb met this requirement with luminous flux of 470 lm and 450 lm, respectively.For Japanese manufacturers, known for their diligence and meticulous work, both Toshiba’s 7.2W LDA7L and Sharp’s 7.8W DL-LA42L met the 485 lm standard, complying with Japan Electric Lamp Manufacturers Association’s guideline specifications.For LG, its 7.5W LED bulb (model no. LB08D830L0A) also met this lm standard. However, the shocker was Samsung. Its 4.4W product only had a luminosity of 270 lm and 320 lm for warm white and cool white, respectively. Such discrepancy was unexpected. Furthermore, other manufacturers like EcoSmart, LEDON, and Feit Electric have also introduced LED bulbs to replace 40W incandescent bulbs, including EcoSmart’s 8.6W LED bulb (model: ECS 19 WW 120), LEDON’s 6W products, and Feit Electric’s 6.5W LED bulb (A19/HP/LED). However, the survey showed that the luminous flux of these products did not hit the 450 lm mark, either.Finally, Osram is in an interesting position, as its cold white LED light bulb reached 450lm while its warm white only had 345lm.In light of the vast standard deviation among different manufacturer’s products, LEDinside points out that the choice of LED light bulbs for the sake of energy saving should be based on not only whether it is an adequate replacement for 40W incandescent light bulb but also its luminous flux.