Again, welcome to 2015. And a happy 2015 it is, at least in energy. Not only have LED lamps fallen in price drastically from just a few years ago, but they continue to improve, in multiple respects. Cree, one of the bigger names in LEDs, didn’t just release their groundbreaking lamp about a year ago. They’re now on their generation-2 product, and yes, competition has improved the breed.
I’ve just installed Cree’s “4flow” LED lamp. I bought this standard Edison base (“A19”) in 40-Watt equivalent. Actual consumption is 6W, saving 34 nega-watts, or 85% less than an incandescent bulb of the same light output. That’s also a savings over a compact fluorescent, though far less. The big trick is getting rid of incandescents, which have only a few percent light efficacy. The other ~97% of the electricity you put in is wasted as heat. Basically, incandescents are little heaters that, oh by the way, make some light too. But unlike fluorescents, LEDs turn on instantly. They’re vibration, cold, and cycling resistant. Their lives aren’t shortened by on-off cycles, such as bathroom and hallway installations. Nor do they contain any mercury, though the mercury level of CFLs has been exaggerated.
The issue with LEDs has been heat- LEDs contain materials that get fried by high temperature. This wasn’t a problem in tiny sizes, like the indicator LEDs on the front of gadgets. There simply isn’t enough power going through to generate much heat. However, for lighting a room, an LED must now be a bigger size, with a greater power throughput. This is the point at which they can cook themselves with their own heat. Every prior room-sized LED implementation has had to deal with this; typically, a large heat sink was visible on the lamp exterior.
The latest LEDs have apparently solved this, and handily. Philips’ LED is made of a plastic with radiator properties, and has a lacrosse/ice-cream scooper shape. The actual LEDs inside were distributed around the “hoop” or rim, and the perimeter then sheds their heat. In the case of this new Cree, the exterior “bulb” is just a shell, to scatter light away but also keep fingers away. This is still possible with vents in the shell, and vents there are.
Philips and Cree have now eliminated the large metal heat sink. Not only did this make the lamps heavier, but cost was increased too. Metal costs more than other materials, both in raw materials and in processing (both cost and energy). A manufacturer that can produce the same results in non-metallic materials will generally do so, saving money and even more energy.
It’s also possible that Cree has developed LED emitters that can tolerate heat better, reducing the need for a heat sink. As the company makes their own LED dies, this would be some sort of competitive secret. It is visible, however, that the emitter dies in this lamp are fewer in number, and further apart than on Cree’s last design. Spacing the emitter dies, like Philips did, helps the heat issue, by keeping each die from being cooked by its neighbors.
The new design and spacing also helps one of the more genuine complaints with the last Cree. That lamp placed its LED emitters in a cylinder, facing outward. This resulted in a ring of light, with possible “dead spots” along the ring axis. One of the dead spots is in the direction of the screw base, which is a dead spot for all screw base designs. But the other spot is then “end-fire,” making the Cree less desirable for a reading or task lamp. Whether or not the dead spot was an issue, or even visible to most people, was a matter of judgement. In any case, the layout of the new Cree eliminates the issue. There isn’t even a dead spot toward the base any more.
There is a genuine downside now. The warranty on this Cree has gone down to three years, from an even decade offered on the prior design. Competition has tightened; I’ve seen no-name LEDs approach Cree prices. I’ll speculate that Cree wants to stay ahead of the game, but in doing so, has had to run faster and farther than they’d like. Yeah, competition’s a bear.
Warranty decrease or not, this lamp is still a money saver compared to incandescents. Let’s assume the electricity rate is 12 cents per kilowatt-hour, the national average. This bulb saves 34 Watts compared to an incandescent. With no direct subsidies, I paid about eight dollars for this LED. To make back, let’s say, seven dollars, this lamp would have to run for 1,720 hours. Assuming four hours a day of light needed, that’s 430 days of operation, or well within its three year warranty. In other words, Cree guarantees you will save money versus an incandescent.
And that’s in electricity costs alone- incandescents don’t last three years of daily use. We might account for the additional incandescents you’d have to buy… and the cost of your labor. For hard-to-reach light fixtures, the projected life of this LED (22 years- that’s right, years- at three hours per day) is easily worth it. For schools and business applications such as storefronts or factories, the duty cycle is much more than three or four hours per day. Replacement will be somewhat sooner, but the energy breakeven point will also be sooner. After breakeven, the LED is now effectively making money versus an incandescent.
Utility or government subsidies may sweeten the deal. The previous Cree and Philips LEDs got a few bucks off, courtesy of my electric utility. Having people install efficient lamps is easier than them building more generation, and upgrading the transmission network. So it makes sense for utilities to steer people toward better bulbs. So far, this Cree shows no visible subsidy in my area; apparently it takes time for someone at the utiity to approve each new product before they grant the discount.
LEDs should be a no-brainer. Should, that is- most people won’t (or can’t) do Total Cost of Ownership analyses like I did above. All they see at first is “eight bucks,” which sounds a bit ridiculous for “a light bulb.” Maybe they see 22 years’ lifetime, and maybe then they get it. Or maybe not. The utilities certainly get it, which is why they’re doing something about that eight bucks.
Efficient lights: get it.