Back in 1990, when I built a new garage and office space at my home in Dummerston, Vermont (where BuildingGreen started out), I installed two sections of Lightolier lighting track with dual switching for use of whatever screw-in lamps I wanted to use in can-type fixtures as well as exposed sockets. During the twenty years since, this has been my little testing laboratory for state-of-the-art energy-saving lamps. I've installed the latest compact fluorescent lamps (CFLs), cold-cathode CFLs, and, more recently, LED lamps. Because I've tried to be out there on the cutting edge (some would say "bleeding edge"), trying out first-generation products as they're introduced, it's a kind-of odd-looking assemblage of lights, some of which are now flickering into a premature demise, others of which have totally failed, and a few that have been working flawlessly for nearly 20 years. (I also had some unfortunate experiences with two generations of early dimming electronic ballasts for a linear-fluorescent fixture in the center of the main space--but that's another story.)

In my anecdotal testing, I was perhaps most disappointed that a warm-white, reflector-style R-30 LED lamp from Lighting Sciences Group that I installed in early 2007 (when we reviewed that product in EBN) has failed. That LSG product used 11 watts to produce 400 lumens (36 lumens per watt) and had a color rendering index (CRI) of 80.

Well, I've just installed Cree's LRP-38 screw-in LED Par 38 lamp in one of those track fixtures, and I love it. The light quality and color are tremendous.

Here are the specifications of the LRP-38:

• 12 watts,
• 500 lumens,
• 4,000 center-beam candlepower,
• 20° beam angle,
• 2700K color temperature,
• 92 CRI,
• and a rated life of 50,000 hours.

The efficacy of 42 lumens per watt is reasonable but far below what some Cree prototypes are providing. In October 2009, Cree announced a prototype screw-in (A-19) LED lamp that produces 969 lumens using 9.5 watts (102 lumens per watt) at a similar color temperature and CRI as the LRP-38. This prototype lamp uses an LED made by Cree that is in commercial production (the XLamp XP-G LED) with the same TrueWhite technology used in the LRP-38.

Cree makes both the actual LED light source used in the product and the lamp (light bulb) itself. It mixes light from red and yellow LEDs to produce the warm-white light, and that light is reflected outward with a many-faceted reflector. The lamp is self-ballasted and has a sophisticated thermal management system (needed with LEDs, because heat has to be conducted away from the actual LEDs). It relies on both a heat-pipe system and aluminum fins to dissipate that heat. With all these components, the LRP-38 is quite heavy--nearly 1 lb, 5 oz, from my measurement.

I used my Kill-a-Watt meter to confirm the LRP-38 power consumption. I found somewhat lower wattage: 10 or 11 watts, vs. 12 (though the difference may be within the accuracy range of the meter). I measured the power factor to be 0.85, which is somewhat lower than Cree literature reports--over 0.9--though, again, inaccuracies of my meter may account for the difference. Power factor, between 0 and 1, is the ratio of the real power flowing to the load (that the utility company sees) to the apparent power of the load (the wattage of the device); the higher the power factor the better.

Introduced in May, 2009, the LRP-38 lamp is finding its way into restaurants and retail stores, where it is replacing halogen and ceramic metal halide lamps. According to a November, 2009 press release from Cree, this lamp will be replacing 70-watt ceramic metal halide in the produce and electronics departments of 650 Wal-mart stores during 2010. (Note that 70-watt PAR30 flood lamps from Philips produce about 3,000 lumens, so in terms of light output, it's not a one-for-one substitution.)

Now the bad news: price. The LRP-38 lists for $199 (that's right--for each one), though I found online prices as low as $140. That's a lot of money to spend for a lamp, even a really nice one! As sales volumes grow and manufacturing efficiencies improve, costs should come down--and, of course, new and even better products will be introduced.

For more information:

CREE LED Lighting

Morrisville, North Carolina

919-991-0700

www.creeledlighting.com

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See more on this product in the GreenSpec Guide