Cree continues to hammer away at the consumer LED lighting market for 60W and 40W replacement bulbs, this time focusing on color quality. Today it introduced its TW (TrueWhite) series of 60W-and 40W-equivalent LED bulbs that have a CRI (color rendering index) of 93 and an R9 value of over 70. (As a reference, an incandescent bulb has a CRI value of 100, while Cree’s standard LED replacement bulb introduced last March has a CRI of 80.) The new 60W and 40W-equivalent versions produce 800lm and 450lm, respectively, and carry Cree’s 10-year warranty.
The California Energy Commission (CEC) recently announced the Voluntary California Quality LED Lamp Specification (PDF), a newer, more stringent voluntary regulation for LED lights than the federal government’s Energy Star lighting program. The CEC regulations set the CRI for LED replacement bulbs at least 90, and the R9 value (which is a measurement of how closely a bulb renders reds) at an R9 of at least 7. Calling LED lamps which meet the standard “California Quality,” the report specifies six areas where LED lamps should exceed the Energy Star guidelines: Color temperature, color consistency, color rendering, dimmability, rated life/warranty, and light distribution.
What good is a voluntary regulation, and at merely a state level? After all, a state commission saying something is voluntary seems to put it in the realm of “nice to have” rather than something that the industry will strive to achieve.
It turns out that the voluntary regulations are pretty potent, because they also say that to be eligible for public utility rebates, the LED lamps must meet these regulations, and rebates are a powerful driver of consumer acceptance. The Sacramento Municipal Utility District (SMUD), one of the largest utilities in the state, has announced that it will be offering a significant rebate for the TW-series Cree bulbs.
The Cree TW series is the first LED replacement bulb to meet the CEC regulations.
What’s the technology behind the TW series? Cree is using a neodymium-glass bulb that acts like an optical notch filter, removing much of the yellow light and giving the light a rosier hue.
Cree is not the first company to turn to neodymium glass to improve color quality: GE’s Reveal line of incandescent bulbs also uses neodymium glass. However, because the neodymium glass blocks so much of the light, the Reveal bulb produces significantly less light than a regular 60W incandescent bulb: Less than 600 lumens vs the 800 lumen baseline output of an incandescent bulb.
The Cree TW series LED bulb faces the same drop in lighting efficiency due to the filtering since the neodymium glass effectively discards some of the yellow part of the light spectrum. Cree’s solution is to increase the lumen output of the bulb before filtering by increasing the power consumed by the bulb from 9.5W in the standard version up to 13.5W in the TW series: You’re trading off Watts for a higher CRI.
Consumers now have the option to purchase a less efficacious bulb and burn the extra 4 W while getting a higher color-quality light, or go for the standard 9.5W bulb and save the power at a lesser light quality. LED lights are efficient enough that consumers can throw a small amount of power away to achieve higher-quality light.
As you’d expect with the higher power rating, the new TW series bulbs have larger heat sinks than the standard Cree bulbs to get rid of those extra 4W. The new TW-series Cree bulb is on the right below. In addition to the larger heat sink, note the faint blue color in the glass bulb, a hallmark of neodymium glass.
The new TW series lights are more expensive than the standard Cree bulbs. The 60W equivalent 800 lumen TW series bulb costs $19.97 vs the standard 9.5W version at $12.97; the 40W-equivalent, 450-lm TW-series bulb costs $17.97 vs the 6W standard version at $9.97. Like the earlier version, they are available exclusively at Home Depot. They will be available online starting
today tomorrow (9/11/13), with the bulbs for sale in the stores on October 1.
SMUD has not yet said what the rebates are for the Cree 60W and 40W equivalent bulbs, but they are probably significant enough to pull the price back down to the close to the original Cree LED bulbs. Look for the SMUD rebates to go into effect on October 1 also.