Back-to-back announcements from Green Ray LED and Philips suggest that there is now clear water between LED and fluorescent lights when it comes to energy efficiency. The proverbial glow of commercially available lights boasting better than 200 lumens per watt efficacy can now clearly be seen radiating over the horizon.
US start-up Green Ray LED claims to have the world's most efficient LED lighting product, a replacement for a T8-type fluorescent tube which emits a remarkable 173 lumens per watt.
This performance is verified by the Department of Energy's Lighting Facts website, a database of lighting products which site visitors can search according to chosen criteria. Sure enough, adjusting the "lumens per watt" slider to search for products with efficacy between 170 and 200 lm/W (which is the maximum the site allows), reveals only one product: a Green Ray RED "replacement lamp" with an efficacy of 173 lm/W.
The 15 W lamp is 4 ft (120 cm) long and emits 2,600 lumens. The pay-off, if there is one, is the lamp's color appearance which, at 5,000 K is distinctly cool.
However, according to Philips, it seems the DoE may soon have to raise the upper limit on that efficacy slider. It has announced a prototype LED lamp at 200 lm/W. The prototype is also tube-shaped (which Philips calls TLED), and though no precise color temperature has been announced, the company claims this is a warm white product. However, Philips says the prototype won't be ready for a commercial launch until 2015.
Combined, these developments are clear signs that LED technology is now pulling away from fluorescent lighting in the race for energy efficiency. Though fluorescent tubes can achieve over 100 lm/W, still excellent by today's standards, compact fluorescent lamps – the kind used as energy-saving fluorescent light bulbs in the home – typically hover around the 60–70 lm/W mark. With manufacturers pouring their R&D budgets into solid state technology, it seems unlikely that fluorescent lighting will fight back. Philips claims that if all fluorescent lights in the US were replaced with its prototype, 100 TWh less energy (presumably per year).
Before too long, it seems 200 lm/W will become the benchmark of excellence that 100 lm/W is today. While throwing these sorts of figures around, it's interesting to note that GE recently launched its best ever "energy-efficient" incandescent halogen light. At 18 and 20 lm/W (according to the figures on the box), the product illustrates the apparent elasticity of terms like energy efficiency, and illustrate the need to promote the lumen and the lumen/watt as the key performance metrics of light fittings. Resources like the Lighting Facts website will hopefully do just that.
Update, 04.13.2013: Philips has been in touch to tell us that its TLED lamp will have a color temperature between 3,000 and 4,000 K, with color-rendering index of above 80. It will initially be offered as a replacement for both T5 and T8-type fluorescent tubes.
Update, 04.19.2013: This article previously stated that a switch to the LED lamps would save 100 TW of power, rather than 100 TWh of energy. Because Philips did not specify a timeframe for that energy saving, this was incorrectly assumed to be an error. Apologies for any confusion caused.
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