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.
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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.
(2010, February 24). Cree's Par 38 LED Lamp a Winner (but expensive). Retrieved from https://www.buildinggreen.com/news-article/crees-par-38-led-lamp-winner-expensive
As a former manufacturer of incandescent lamps who lived through the birth of LED applications in flashlights and now general lighting, I find this to be a very worthwhile report that puts the product in the context of the efforts to improve lighting over the last 20 years, and Alex Wilson's efforts in particular. He is doing all of the right things in terms of evaluation criteria and comparison testing.
The efficacy of LED's is improving at a phenomenal rate, like any other semi-conductor product. One of the manufacturers, Cree, I believe, has nearly commercial LED's in the 200 lpw range.
When one considers efficacy and life, as well as aesthetic performance, LED's are close to becoming a viable replacement for incandescent and fluorescent lamps. And as volumes (capacity, etc) increase, the prices will be coming down significantly.
Ok, so it produces a lot of lumens per watt, but how green is it really?
Will the total energy bill for its design (all those man/woman-hours spent slaving over a hot CAD workstation, endless testing etc.), tooling, manufacture (including all the complicated (and non-recyclable) electronic gubbins, heat pipe etc. within the housing, plus the energy in use really be less than that for an incandescent lamp with a power factor of 1, near-zero manufacturing costs and designing and tooling costs which were probably amortized more than 50 years ago that sells for peanuts?
Perhaps somebody should do ALL the math.
They need to get the CR6 made into bulb form instead of the integrated trim. And at the same price Home Depot is selling the CR6 for. $50. This makes the ROI worthwhile even in an area of occasional use.
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