Cree 60w warm white LED review and comparision

Background

We've been using CFL bulbs for a number of years.  The good new about CFLs is that they use less electricity than incandescent light bulbs - typically about 1/4 as much.  Their pricing is less than LEDs today, but still more than incandescents.  But they have a number of disadvantages, too:

• The quality varies greatly from brand to brand.  The off-brands may be cheaper, but typically exhibit most of the bad points listed below.  And even the top-tier brands exhibit some.
• They're slow to reach full brightness - often taking a minute to more than 10 minutes(!) to get close to full brightness.
• They get dimmer with age.  The cheap brands in particular seem to lose about 1/3 of their brightness after a couple of years.
• Their lifetime is significantly shortened by repeated on/off cycles.  Yes, they may last 25,000 hours if left on all the time, but in a room where they're turned on & off a lot (a bathroom, for example), they might last half as long, if that.
• They contain mercury, which makes them a hazardous material and thus they require special procedures for disposal.
• Early CFLs were very "cool" - they had a color temperature in 5,000° Kelvin range, so their light had a distinctive bluish cast, unlike incandescents, which are typically much "warmer" (3,000° Kelvin or so) and cast a more yellowish light.  Current CFLs are available with a "warmer" tone to them, but you have to look for them.
• Early CFLs were not usable in dimmers.  In fact, they would typically be destroyed by such use. There are special "dimmable" CFLs available now, but they're typically more expensive than the non-dimmable units and are often not "full range dimmable", meaning that if you try to dim them all the way, they'll typically turn off at around 40% brightness.

So with all of that in mind, I've been looking at alternatives.  LEDs are a better technology, IMHO - hazardous material-free, even more energy conservative than CFLs and most are dimmable.  But they've typically been pretty expensive ($30-$40 for 60 watt equivalents, $50+ for 100 watt equivalents).  Because they typically need heatsinks to cool their electronics, they've often been designed in unusual shapes, many of which are either aesthetically displeasing, or won't fit in many places where A-type incandescents do - table lamps with harps or lampshades which clip onto the bulb, for example.  Early CFLs had similar issues, but most are now packaged to be closer in size to traditional A bulbs.

Cree 60 watt equivalent LED

Cree just introduced a line of inexpensive 40- and 60-watt equivalent LED A-style light light bulbs about a month ago.  What makes them relatively unique in the market is their price.  Home Depot is selling them for $9.97 for the 40-watt and $12.97 for the 60-watt.  They've been getting good reviews elsewhere on the 'net, so I rode down to my local Home Depot and picked one up to try.  I pulled a couple of CFLs out of lamps (one 60-watt equivalent, one 100-watt equivalent) as well as a 60-watt incandescent to serve as the "standard candle".

The bulbs used in this comparison - L-R:
GE 26w dimmable CFL, Generic 20w CFL,
Cree 9.5w LED, GE Long Life 60w incandescent

Statistical comparison

Lighting technology comparison

Type of bulb	Equivalent Incandescent watts	Measured Watts	Measured VA	Measured Power Factor
GE Long Life White 60 watt incandescent	60	57	57	.99
GE 26w Dimmable CFL	100	25	36	.67
Generic 20w CFL	60	20	40	.50
Cree 9.5w Dimmable LED	60	8	10	.74

As you can see, the energy consumption of the LED is less than half of either CFL and only 1/7 of the incandescent!  You can also see by the Power Factor rating that the generic CFL is of inferior quality to the brand-name unit.  It's basically less efficient.

Now on to what you want to see - the pictures.  What about light quality?  Color?  Intensity?  All of the shots below were taken with a Canon EOS T3i set to manual exposure, 1/125 at F4.5 to ensure that they are as comparable as possible.

Pictures

Floor lamp

GE Long Life White 60 watt incandescent

GE 26 watt dimmable CFL
(100 watt equivalent)

Cree 9.5 watt dimmable LED
(60 watt equivalent)

You can probably see that the 100-watt equivalent CFL is somewhat brighter than either 60-watt lamp, but the color of the LED more closely matches that of the incandescent.  All were roughly similar in color temp - I'd call it "warm white", probably in the 2,800°-3,200° K range.

Table lamp

Cree 9.5 watt dimmable LED
(60 watt equivalent)

Generic 20 watt CFL
(60 watt equivalent)

In a table lamp (sans shade), the light color and intensity is very close between the two 60-watt equivalent energy saving lights.  But I found it easier to replace the harp with the LED bulb due to its more conventional shape.

LED light dispersal

By stopping down the camera lens, I was able to get a better idea of the light dispersal characteristics of the Cree LED.  As you can see, there's considerably less output from the top (and bottom), making it a less-suitable candidate for spot or downlight applications.  It's ideal for table lamps, where most of the light should come out of the side of the bulb.  

Light dispersal of Cree LED
Note band of light in center, dropoff at top and bottom

Dimmability

I tested the Cree LED against the GE dimmable CFL in a wall sconce controlled by a Lutron wall dimmer switch.  The CFL dimmed about 40% before going completely dark when the dimmer slider was at about the 30% mark.  The LED kept getting dimmer throughout the range of the dimmer slider.  In addition, with the dimmer at its lowest level, I was able to turn off the LED and then turn it back on, while the CFL stayed dark when the switch was toggled.

Summary

I've only had the LED for a couple of hours now - not really enough to make a good comparison, but the combination of energy efficiency, dimmability, relatively low cost and lack of hazardous materials make the Cree seem like a winner.  I'll probably pick up a six-pack on my next run to Home Depot.

One More Thing...

I have nothing to do with any company mentioned other than as an interested consumer.  And in that vein, there's another technology on the horizon that may also prove a lighting game-changer.  It's called ESL (Electron-Stimulated LuminescenceTM) and the company closest to commercialization is VU1 with their 65-watt floodlight replacement.  They hope to have product in the marketplace later this year.  I have an application, so I'll likely pick up one as soon as I can.  If you know of other good lighting products, feel free to leave a comment!