# New Design of Cree Bulbs-Now Ventilated



## velvetfoot (Jan 2, 2015)

I was in HD today and noticed the design of the 40 and 60 watt equivalent Cree bulbs has changed.  They are now ventilated.  They seem lighter.  Any users/opinions?


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## Former Farmer (Jan 2, 2015)

Comparing the old style to the new style :

Old     9.5w   800 lumen   2700K   10 year warranty
New  11.0w   815 lumen   2700K     3 year warranty

I would stick with the old style.  Cost $2.00 more per bulb, longer warranty and lower power consumption.  Would probably never recoup the additional cost in energy savings, but may use the extra warranty.


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## vinny11950 (Jan 2, 2015)

I got one of those, 1600 lumens, daylight spectrum.  $20.  I wanted something to really light up the room in the cold, gray winter days to help cheer me up.  It is bright, but the spectrum is not as close to daylight as I wanted it to be.  I get much more happy when I go to the local hydroponic store and walk around their grow lights.

Overall, though, not bad for the price.


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## Former Farmer (Jan 3, 2015)

Also noticed that they are approved for use in enclosed fixtures.  Not many led bulbs are approved for enclosed fixtures.  The ventilation openings in the bulb must allow more air to circulate around the bulb to help keep it cool.


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## velvetfoot (Jan 3, 2015)

I wonder how they work in an exterior fixture.


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## Former Farmer (Jan 3, 2015)

I don't know if snow could get into the bulb itself?  Would not be good when you turned the light on and poof - magic smoke.  Electricity and water don't play well with each other.


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## dznam (Jan 3, 2015)

velvetfoot said:


> I was in HD today and noticed the design of the 40 and 60 watt equivalent Cree bulbs has changed.  They are now ventilated.  They seem lighter.  Any users/opinions?



IIRC, the CRI of the newer cree bulbs is much better (provide a truer rendering of color which was/is an issue with LED bulbs). I believe this is accomplished by a coating on the bulb which filters part of the LED light's color spectrum, which is quite different from that of sunlight (the basis for CRI comparison). Thus, it requires a little more power to produce a similar light output (lumens) because some of the light is being produced is being filtered (reduced) by the coating.

Having seen and used both bulbs, I would choose the newer one every time, it is a much more pleasant light and closer to an incandescent. What's $2 over the 10,000 - 25,000 hour lives of these bulbs?


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## velvetfoot (Jan 3, 2015)

It looks crappier.


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## Where2 (Jan 3, 2015)

Unfortunately, my most demanding use enclosed fixtures have a lid on them.  I nearly bought some of the old style Cree 40W TW bulbs today on clearance for $6.50 each. 10 year warranty, ok for enclosed fixtures, CRI=93. 450 lumens for 8.5W was the kicker. I'm spoiled to my 9W 800 lumen 60W equivalent units.


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## woodgeek (Jan 4, 2015)

dznam said:


> IIRC, the CRI of the newer cree bulbs is much better (provide a truer rendering of color which was/is an issue with LED bulbs). I believe this is accomplished by a coating on the bulb which filters part of the LED light's color spectrum, which is quite different from that of sunlight (the basis for CRI comparison). Thus, it requires a little more power to produce a similar light output (lumens) because some of the light is being produced is being filtered (reduced) by the coating.
> 
> Having seen and used both bulbs, I would choose the newer one every time, it is a much more pleasant light and closer to an incandescent. What's $2 over the 10,000 - 25,000 hour lives of these bulbs?



Nice.  I bought some high-CRI LEDs a while back (the L-prize from phillips), and a bunch of cree for undemanding applications, but I have been waiting for the CRI to come up before I really replace everything.  I poked around last week, and it seems the high CRI Crees all have the blue coating, right?


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## Former Farmer (Jan 4, 2015)

woodgeek said:


> it seems the high CRI Crees all have the blue coating, right?


Yes.  They are the TW ones.


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## woodgeek (Jan 4, 2015)

TW?  Anybody care to provide a URL for the new bulbs so I can have a look, rather than guessing?


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## Former Farmer (Jan 4, 2015)

http://www.cree.com/Lighting/Landing-Page/Cree-Bulb

***Why is it blue?* The rare earth element neodymium is added to the glass of our Cree TW Series LED bulbs to augment the LED light. This creates a “spectural notch,” allowing the LED light passing through the glass to show colors that are *true and natural*.


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## velvetfoot (Jan 4, 2015)

This is the 2700k bulb I was looking at:  http://www.homedepot.com/p/Cree-60W...9-08027OMF-12DE26-3U100/205597078?N=5yc1vZbol


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## Former Farmer (Jan 4, 2015)

velvetfoot said:


> I wonder how they work in an exterior fixture.



Certifications: UL Damp Rated


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## woodgeek (Jan 4, 2015)

Thanks guys.  Drilling down on those the CRIs are not that great.  They say  '>80', about the same as a cheap CFL.

I found these Blue Cree Edison bulbs: http://www.earthled.com/products/cr...-13-5-watts-60-watt-equal-93-cri#.VKk6W4BUNBs

that have a CRI of 93.  FF's link shows that the blue tech has shown up in the reflector bulbs, but not in the edisons in HomeDespot, yet.

Aaah, now I get it, the 'TW' series.  Looks like the lum/W are lousy though....maybe 60 or so.  My L-prize bulbs got the CRI by adding in red emitters IIRC, and got a much higher lum/W at the same high CRI, before they were discontinued....


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## velvetfoot (Jan 4, 2015)

Those high-CRI bulbs are high K as well, no?  Personally, I hate the 'brightness' and go with the 2700.
edit:  I take that back and actually clicked on the link, lol.


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## woodgeek (Jan 4, 2015)

Nope.....The TW series are 2700K


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## velvetfoot (Jan 4, 2015)

$9 per is hard to take.  $20?  Wow.


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## woodgeek (Jan 4, 2015)

Yar.  I think I'll be waiting a little longer for something that has both CRI>90 and lum/W>90.


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## velvetfoot (Jan 4, 2015)

Why is the high CRI so important to you?  I find the ones I'm using, 80?, to be not obviously strange.


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## woodgeek (Jan 4, 2015)

In the kitchen and dining room, high CRI keeps your food from looking weird.  I **imagine** that the spectral features of the color molecules in food can exaggerate color effects.
I also notice that my clothes look different in low CRI lighting relative to outdoor lighting or daylighting, and often have subtle discolorations or stains that are 'plain' in daylight and invisible when I got dressed.  This might be a WW Kelvin effect.

Bottom line: if I am shopping for a bulb to use for *20 years* in my dining room or dressing area.....I want something that shows true colors.  Garage, porch or living room, not so much.


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## jebatty (Jan 4, 2015)

My brain does a pretty good job of color correction all on its own. Once the brain gets used to different color rendering, everything returns to "normal." What are colors, anyway? Just our eye-brain rendering to something with which we are familiar. Animals see "color" much differently. Personally, I like the 3000K much better than the 2700K which are much too red for me. And for outdoor lighting, basement, and any other areas that need "bright" light, the 5000K are my choice. I think it is a mistake to imitate incandescent, which is a technology of the dark ages.


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## woodgeek (Jan 4, 2015)

I agree with you completely regarding color temp.  Your eyes adjust.   Midday sunlight is actually v blue 5000K light, but looks warm to the eye.  This makes sense since the effective color temp of natural light varies significantly with time of day and weather conditions.

We disagree about CRI though.  Your eyes don't adjust to it because low-CRI lighting just presents less color information to the eye, so there is nothing to adjust.  I can stand in a sodium light forever, and I will never start to see colors normally, everything will just keep looking gray. 

The folks that care about this, and are CFL-haters are not making it up...they can see a difference they don't like.


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## dznam (Jan 5, 2015)

jebatty said:


> My brain does a pretty good job of color correction all on its own. Once the brain gets used to different color rendering, everything returns to "normal." What are colors, anyway? Just our eye-brain rendering to something with which we are familiar. Animals see "color" much differently. Personally, I like the 3000K much better than the 2700K which are much too red for me. And for outdoor lighting, basement, and any other areas that need "bright" light, the 5000K are my choice. I think it is a mistake to imitate incandescent, which is a technology of the dark ages.



The CRI scale is based on the color of sunlight... the most natural of light. It just so happens that incandescent lights apparently provide color rendition that is very close to sunlight (albeit at a different K). I'm with Woodgeek on CRI - you don't "adjust" to an unnatural CRI - it's always noticeable. Probably because we're provided with a constant reference source for light color: sunlight. There's another index for the color red, specifically, which is very important for retailers and food stores and allows the natural and attractive attributes of the color red to be displayed. Most all commonly available LEDs are pretty mediocre at this.


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## dznam (Jan 5, 2015)

jebatty said:


> My brain does a pretty good job of color correction all on its own. Once the brain gets used to different color rendering, everything returns to "normal." What are colors, anyway? Just our eye-brain rendering to something with which we are familiar. Animals see "color" much differently. Personally, I like the 3000K much better than the 2700K which are much too red for me. And for outdoor lighting, basement, and any other areas that need "bright" light, the 5000K are my choice. I think it is a mistake to imitate incandescent, which is a technology of the dark ages.



Interesting reading from:

http://www.energy.ca.gov/2012publications/CEC-400-2012-016/CEC-400-2012-016-SF.pdf:

Color Rendering

Color rendering is a measure of how true the colors of objects look under a light source, as compared to how they look under a reference light source of the same (or similar) color temperature. The two most common reference sources are an incandescent lamp at 2700K and a typical spectrum of daylight at 6500K (known as “D65”).

The most common metric of color rendering is the Color Rendering Index (CRI). A CRI of 100 indicates that a light source renders a particular palette of eight colors in exactly the same way as the reference light source to which it is being compared. A light source with a CRI significantly less than 100 typically makes one or more of the eight standard palette colors appear more gray (less saturated) than the reference source, although a low CRI can also arise because a light source renders certain colors as being too saturated. An incandescent lamp is considered the ”reference” light source for all lamps with color temperatures less than 4000K, so by definition incandescent lamps achieve a CRI of 100 because they are being compared to themselves.

It is important to realize that color rendering is not necessarily a measure of “naturalness” or “saturation” or “quality”. The CRI metric was developed for industrial purposes, when color checking was carried out by human observers, to prevent observers confusing one color with
another (“metamerism”). The CRI metric was not optimized to describe viewers’ subjective preferences for color balance or saturation. Other metrics have been and continue to be explored to quantify viewers’ subjective preferences for different light sources and for the colors of rendered objects, though none has replaced CRI as the primary metric. In particular, the National Institute of Standards and Technology (NIST) is continuing work on the Color Quality Scale (CQS), though at the time of writing there is no specific schedule for development of a new metric.

Despite the various minor shortcomings of the CRI metric that have been noted by researchers, it is a reliable and meaningful scale toward the top end (that is, at values approaching 100 CRI). This is because the only way to achieve such high values is by using a nearly continuous spectrum, by using multiple phosphors or LED chips to give almost‐equal weighting to all spectral colors. Natural daylight also has a continuous spectrum. Therefore, a light source that approaches 100 CRI will be perceived by consumers as being colorful and natural, as well as rendering colors accurately.

The images in Figure 4 demonstrate the difference between low CRI and high CRI. In the picture on the left, which represents a 50 CRI light source, the pink, red, and orange pencils are hard to distinguish from one another. In the image on the right, representative of a 90 CRI light source, the colors are much more easily distinguished. (These images are for illustration only and should not be taken to accurately represent the actual appearance of objects.)

Figure 4: Comparison of Color Rendering Index of Different Light Sources

Source: Lighting Matters’ LED Blog, lightingmatters.com.au/blog/ledlight-quality-cri/

In addition to quoting CRI, LED manufacturers have begun to quote the performance of their products in terms of how they render a ninth color (“R9”—a saturated red color). This is, in part, because a high R9 value indicates improved rendition of important common materials (skin tones, earth tones, woods and vibrant red colors). It is also because manufacturers wish to distinguish “good” LEDs from “bad” LEDs, and from typical triphosphor T8 lamps, which do not render the R9 color well. R9 performance is defined on the same scale as the CRI, although values are often much lower, or even negative, because manufacturers have historically not optimized their lamps for R9 performance. Typically the R9 value for T8 lamps is 10‐20, whereas LEDs are currently available that achieve over 50.

Because CFL program evaluations did not identify color as a key factor, improved color performance was not demanded or encouraged and was therefore abandoned in favor of lower cost. Innovation and new investment in color were hard to justify and largely not pursued by mainstream manufacturers.

However, color rendering has become a more widely discussed lamp attribute, and some manufacturers in the blossoming LED lamp industry are already striving for improved CRI in their products. As of May 30, 2012, the U. S. Department of Energy’s SSL Lighting Facts product database contained 123 replacement lamp products with a CRI of 90 or better. Because the LED market already includes a large number of products with high CRI, and because color quality has been identified as a key opportunity for improvement, the specification includes a minimum requirement for color rendering index.


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## jebatty (Jan 6, 2015)

A quick search on the eye and color/brightness/contrast perception and the discussion on K, CCT and CRI shows all of this is more complicated that "first meets the eye." Lighting


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