Anyone try the new Cree Bulbs yet?

http://www.homedepot.com/p/Cree-9-5.../203991774


They are a game changer at this price point.  The lumens looks good, but I see the CRI is only about 80.  I was wondering how they make objects look in the home.  Do they give a hollow cast or do they look warm and inviting?  How do reds look?  How good is the color when dimmed, etc.

I am only interested in feedback for the warm white 60 Watt version.

These looks like the beginning that will start the march of the masses to LED.  Might be the goodbye for slow starting CFL's.

I have a bunch of the 6" Cree's in my recessed can fixtures and they are just awesome for color and dimming.  They have a better CRI, so I was curious how these new A19's stacked up.

Thanks.

Over its entire lifetime, it will save about $6 over a CFL in energy $. But it costs $8 more. Buy these if you value the other differences (eg. dimmability, fewer replacements). Or you have high electricity costs and it will be on for quite a few hours/year.

Yes, i would buy them for instant on(very important) and dimming. I'm looking for feedback on light quality, not ROI and comparison to CFL. There are plenty of those posts already. I am aware of the costs over the lifespan between the two types of lights. Thanks.

Note: a few of CFL's I have bought have died way before there rated life, so the value in those cases is lost. The CFL is great where the light is always on, you don't dim, you don't see the bulb itself. I think CREE is a company that is all in, so to speak, and is making a quality product that can be trusted.

Looking for any real life users out there.

The Home Depot forum has lots of real life user comments. Evidently there have been failures "the first bulb stopped lighting today (the 10th): a little more than two days after I bought it." and the color changes as you dim it (gets bluer). But overall - good reviews.

Yes, some good comments over there and I also see and they come with a 10yr warranty if they fail.

Looking for some comments from this crowd that tend to be more decerning than the Home Depot reviewers on the light quality.

There's a perception with with most LED and dimmable fluorescent technology that they all grow bluer or "colder" as you dim them, but that's primarily an artifact of eye response with intensity, not a true shift in color balance. (I haven't seen the new Cree though, it may really color-temp with dimmed output, but that would be unusual.) There's also some built in expectation of the red shift that occurs with dimmed incandescent technology.

Multi-element LED assemblies could arguably be designed to compensate for the eye response issues and/or generate a "warming" red shift to a lower color temp at lower light levels, but it probably come at a cost in color-rendering or unit-to-unit color temp differences at different dimming levels.

Cree and Philips are both dedicated to an LED future, as is Sylvania. It's a competitive marketplace, and the prices WILL come down, as both quality and efficiency climb. At the $13 market-entry point of the 9.5W 800 lumen Cree we're already at 50% price reduction and a ~50%+ boost in efficiency over what was available in LED A-bulbs just 3 years ago. It's not a stretch to think we'll be seeing efficiencies north of 100lm/W in A-bulbs at that price point or even lower in fairly short years. It's a competitive race to see who gets to own your sockets for10-20 years at a time, but the days of high-volume production short-lifecycle incandescents are numbered.

Temperature and CRI aren't great indicators of light quality and incandescent will always be most accurate. If you happen to have your walls painted a color that the bulb is missing - they will look darker. You might have to buy one and try it....

The spectral lines of most of the better LED assemblies are greater in number and much broader in width than the typical single-phosphor + mercury-argon fluorescent technology that typically has with three, sometimes four peaks in the visible region. With LEDs the sprectrum is smeary, not spiky, and with only modest help from phophors to fill in where needed, multi-LED assemblies have remarkably smooth specrtal output.

Most mid to high CRI LED assemblies use two or three fundamental LED types (blue, red, and amber), with phosphors generating multiple additional lines in addition to the smeared-spectrum of the fundamentals. Ever popped open a Cree downlight for a peek?

http://img.photobucket.com/albums/v653/LEDmodMan/light_stuff/IMG_5202.jpg

The resulting spectrum, while not a perfect simulation of blackbody radiation, is a much smoother curve in the middle-portion of the visible spectrum (usually with a fat spike on the red end of a "warm white"), but NO missing lines:

http://www.creeledrevolution.com/bl...bution.jpg

Not sure how many die types or phophors are used in the new Cree A-bulbs, but I'd expect it to do way better at color rendering any paint colors than any single or 2-phosphor fluorescent, if not as well as the very best (and fairly expensive) 90+ CRI linear fluorescents (that run comparatively lower efficiency due to the raw amount of phosphor paints of different types coating the interior of the tube. Typical 1-phosphor fluorescents have spectra along the lines of this:

http://www.intelab.com/klite/spec_disc.jpg

Which has a lot of potential for color distortion on select paint colors.

Cheap incandescent's have a real dearth of blue in the spectrum, but even smoother spectral output. Better incandescents have long since added phosphors on the inside of the bulb to pump more into the blue end, sometimes robbing quite a notch out of the red end:

http://www.lrc.rpi.edu/programs/nlpip/lightinganswers/fullspectrum/img/figure1-r.gif

The high CRI high lm/w Philips L-prize winner has a small deficit in blue and a big spike in the red at the edge of human eye response, but a very nice, smooth curve overall:

http://www.molalla.net/members/leeper/L%20Prize%20Bulb/L-Prize%20vs.%20Incandescent.png

You might have an issue with it if you painted your walls midnight-blue (making them look darker-than-already-dark ;-) ) but you'd be hard pressed to see much distortion in other colors of wall paint.

Spectrum is yet another reason why LEDs are destined to overwhelm fluorescent technology going forward.

(edited to fix links)

I bought six of the new 2700K, 60 Watt equiv Cree A19's, the day that they officially went on sale. So far I'm pretty happy with them. They've seen a few hours of use each day; no problems so far. I like them better than the Phillips 60 Watt 2700K bulbs (not the L-prize bulb -- these are the ones that are 13.5 watt, I think?) The phillips bulbs take about 1/2 a second to turn on, and they buzz a bit. The Crees turn on instantly and do not buzz.

The color rendering of the Cree A19's isn't quite as nice as the EcoSmart/Cree downlights, but it's still pretty good.

I don't have any dimmers on the downlights or A19's, so I have nothing to say about dimming.

Jeff

I'll make a somewhat educated guess that if you dim these bulbs down a little bit, efficiency will go up a little and the life will increase significantly.

Expect some extra orange color with these bulbs.

jonr,

Will the bulbs use less electricity when they are dimmed?

Certainly, as will any dimmable bulb. But even more interesting is that I believe that they will also produce more lumens per watt when dimmed (unlike an incandescent bulb).

Posted By jonr on 19 Apr 2013 10:32 AM
Certainly, as will any bulb. But even more interesting, is that I believe that they will also produce more lumens per watt when dimmed (unlike an incandescent bulb).

I agree, or at least seem to see that on my recent LED retrofit

I just did undercab kitchen LED lighting using high CRI 2700K flexible strips.  I used a Lutron 120V dimmer feeding a magnetic transformer, then to the 12V DC light strips.  I paid a nice premium on the high CRI strip vs std, but the result is just awesome (Passed the wife-o-meter test with very high marks).  Meat, tomatoes, and vegies look correct.  I tried the cheaper, not high CRI strips, and the food looked gastly when we tested.  I ended up putting those stips in a hutch and they look pretty good there.

Anyway, I have a TED 5000 energy monitor so I can see power use real time.  If I set the dimmer at full power, they complete undercab set consumes about 40 watts total and are nice and bright.  If I set the dimmer slightly lower to yield about 70% of the percieved full brightness, the energy use drops to about 18 watts.  Quite a drop.  I did not test lumens, just percieved intensity in real use.  Thet is where we keep it set most of the time.  The color is slightly less warm at this setting, but still very nice.

I seems when you push these LED's to the design limit on power, more energy goes to heat and slightly more into the yellow/red spectrum.  Or, at least apprears that way in my case.

Iteresting charts Dana posted.  Flourescent is more spikey that I thought...

And thanks for the feedback on the Cree A19 60W.  They seem promising on all measures.  My wife and I are just very picky on the rendition of the colors, so any feedback on that is greatly appreciated.

Posted By jonr on 19 Apr 2013 10:32 AM
Certainly, as will any bulb. But even more interesting, is that I believe that they will also produce more lumens per watt when dimmed (unlike an incandescent bulb).

Not necessarily- there are multiple factors going on, including the rectification losses on the power supply as well as in the SCRs junction in the cheap dimmers themselves, and the non-linear luminous response with current of the LED elements themselves.  Most LEDs go up in lm/watt with increased current as long as they maintain a constant temperature, but they also heat up, and there's an optimal temp for luminous efficiency too.  In general luminous efficiency degrades with increased temperatures over 25C, but not too rapidly. Whether the lowered temp from dimming is sufficient to overcome the inherent rectifcation losses and the non-linear efficiency numbers of the constant-current DC supply feeding them is unlikely.  Most of those constant current supplies hit their peak efficiencies toward the high-end of their output (the highest current, brightest output).  It's not a simple model.

The fact that the eye's response is logarithmic means that it takes fairly drastic reduction in luminance before visual efficacy is degraded, so dimming does in fact reduce total power use by quite a bit, even if the lumens per watt goes up when dimmed back.

IMO, dimmable LEDs or CFLs are a valid energy savings technique. The light level that you need most of the time is far below the level that you occasionally need.

Most LEDs go up in lm/watt with increased current as long as they maintain a constant temperature

The net change is that lumens/watt go down significantly with increasing watts while power supplies tend to have little change in efficiency over a fairly wide band around their maximum efficiency. Ie, something like a 2% drop in power supply efficiency vs a 20% increase in light efficiency is a great trade-off.

But it would be interesting to see actual data for these bulbs.

http://www.candlepowerforums.com/vb/showthread.php?343702-LED-measuring-lumens-efficiency-and-spectral-characteristics