LED lights, marketing vs. reality

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LED lights, marketing vs. reality

Postby zzsstt » Sun Feb 13, 2011 8:48 am

Recently I have again been looking at LED lighting. As the Labor government looks determined to reduce its debt by implementing a carbon tax, I can see the price of electricity (and everything else) rapidly escalating, so once again a reduction in power usage looks sensible.

As always, the problem lies in sorting the marketing from the reality. Looking for a nightlight for the kids bathroom, I coudn't help but notice the "85% power saving" claims on an LED plug-in unit. Now 85% is a worthwhile gain, except that 85% of almost nothing isn't actually very much, and a normal nightlight of 5W will only use about 1kwh (23c) of electricity per month. So the "85% saving" equates to about $2.50 a year.....

However, having several large sheds and commercial properties using many 1200mm fluoros, I thought I'd investigate options for LED T8 tube replacements. These are fairly common, and their prices vary a fair bit. However reading the specs indicates that the "tubes" also vary substantially. On eBay at present a company is selling 18W 1200mm T8's LEDs for $29 each. BUT, reading the small print this is for "amber white" tubes, and the warm white (or cool white) are $39. Reading the small print further, the cool white "tubes" output 1200lumen, whereas another company (not on eBay) is selling 18W T8's that output 2020lumen, 1.6 times as much light for the same power. The second company claim:

"The 22watt T8 long white tubes provide the equivalent light output of 36 to 40-watt fluorescent tubes while consuming less than a maximum of 18watts.The xxxxx T8 LED Tube delivers up to 2,112 lumens at a color temperature of 6500K (cool white) and 1,950 lumens at a color temperature of 3000K (warm white), compared to the average 810 lumens for equivalent conventional fluorescent tubes."

Which sounds very impressive, except that a conventional 1200mm 36W T8 actually outputs about 3350lumen, not 800 as stated in the "hype"!!

Then of course we have the ballast for the fluoro, which the LED hype claims is 10W. In fact an electronic ballast uses about 4W, so the 36W fluoro uses 40W.

The maths then becomes;

22W LED = 2200lumen = 100lumen/watt
40W fluoro = 3350 Lumen = 83lumen/watt

So a 17% saving. But the cost? A 1200mm T8 costs about $4. The LED costs $80.

Running 10 hours a day 5 days a week the LED will cost $13/year, the fluoro would cost $24/year.

Assuming it's full lifetime of 50,000hours the LED would cost 0.7c/hour to run.
Assuming a lifetime of 10,000 hours for the fluoro (rated between 6000-15000hours depending on brand), it would cost 0.96c/hour to run.

However, the story does not end there. In fact to maintain light levels I potentially need >1.5 LEDs to replace a fluoro (3350lumen vs. 2020lumen). So the LED now costs almost exactly the same to run as the fluoro. And takes a massive capital investment to do it, money which could be invested earning more money. And it relies entirely on the LED actually going the distance, and many people have found that after their initial delight, the LED's don't last more than a year or two - and we're talking 19 years to makes the maths work!The warranty offered is only 2 years, nowehere near long enough to cover the risk, and again many people have found the retailers no longer exist a year later, making the "warranty" worthless.

Of course the price of electricity will increase, but the cash in the bank will still be making money.....

Because of the other issues like reflector cleanliness and heat, there is of course the potential that the LED may have other real world benefits. But it still doesn't look good when the maths is done and the hype is discarded!!

Once again, I think I'll keep my money in my pocket!!
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Re: LED lights, marketing vs. reality

Postby Think Wise » Thu Mar 10, 2011 4:04 pm

I will try to help out if possible.

Currently I have just had one of our tubes Nata tested. The 19w came out at 1600lumens (89lm/w) which admitedly was one of the higher lm/w he had tested :)

although a 36w Fluro is 3350 lumens not all of that light reaches the ground usually a luminaire will have a factor associated with it.

I have a 2*t5 troffer report also and total lumens emitted for the 60w was 2941 (48lm/w)

This really only clears up the lumen difference but it might help your payback solution as well.
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Re: LED lights, marketing vs. reality

Postby Think Wise » Sat Mar 12, 2011 5:53 pm

lumen output of the tube and lumen output of the fixture are two different things.

a t8 ceiling troffer does not output 6000lumens+ probably closer to the region of 3000-3500

That said a LED tube does not put out 100lm/w either!

I have seen cases where 2x20w LED tubes out perform 2 x36w t8 but you are correct in saying the cost variance is hard to justify without certain circumstances 24hr operation, food areas, high ceilings etc.
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Re: LED lights, marketing vs. reality

Postby zzsstt » Sun Mar 13, 2011 4:36 pm

The average troffer efficiency according to the manufacturers is about 74%. So the fluoro troffer would be expected to output about 4900lumen.

Further research indicates that I'm not the only one who has concluded that these LED devices are nowhere near as good as they are claimed to be. A report prepared for the US Department of energy in 2009 (http://apps1.eere.energy.gov/buildings/publications/pdfs/ssl/troffer_benchmark_01-09.pdf) makes the following statements. An "executive summary" of the report would be that the replacement LED's are nowhere near as good as the fluoro's, and that the marketing and advertising for the replacement LED's borders on outright lies!

"CALiPER testing of currently available LED replacements for 4-ft T12 and T8 fluorescent lamps indicates that although LED linear replacement lamps are marketed as one-for-one drop-in retrofits for general fluorescent applications, their comparatively low light output could result in unacceptably low illumination levels in retrofit applications. Although there may be some niche applications in which the lower light output, superior cold-temperature operation, and potentially longer life of LED linear replacements are indicated, CALiPER testing at this time shows that LED technology is not yet ready to displace linear fluorescent lamps as replacement light sources in recessed troffers for general interior lighting."

And in answer to your specific comments about directionality and troffer efficiency:

"Manufacturer literature for some LED linear replacement products argues or implies that—by virtue of their directionality—the LED products achieve equal or greater illumination levels with far less overall lumens compared to fluorescent products. Similarly, manufacturer literature for LED replacements also typically implies that they provide energy savings as compared to similar fluorescent products."

"Product literature often implies that, given their inherent directionality, LED replacement lamps can achieve equal or greater luminaire light output (and illumination levels) with far less total lumens compared to fluorescent lamps. CALiPER in situ tests of linear replacement lamps in typical troffers allow us to examine fixture efficiency, luminaire efficacy, and light distribution from troffers equipped with these LED linear replacement lamps as compared to linear fluorescent lamps.
CALiPER in situ test results for two-lamp lensed and parabolic louver troffers confirm that—independent of their light output and efficacy—LED linear replacement lamps achieve higher fixtureefficiencies than T12 and T8 fluorescent lamps in the same fixtures (Table 5). In the lensed troffer, fixture efficiency when operated with LED replacements lamps is 11% to 17% higher than when operated with linear fluorescent lamps. In the parabolic louver troffer, fixture efficiency with LED replacement lamps is 14% to 26% higher than with linear fluorescent lamps. However, even with this increased fixture efficiency, the best-performing LED replacements could not deliver even one-half the light output of the benchmarked fluorescent sources when operated in situ in troffers."

"As shown in Figure 6, CALiPER-measured light outputs for currently available LED linear replacement lamps fall far short of measured light output for benchmarked T12 and T8 fluorescent lamps. In these samples, the best performing bare lamp using LEDs produces only one-third the light output of a typical 4-ft fluorescent lamp."

"Lamp efficacy is the light output of a lamp divided by its power usage, expressed in lumens per watt. As illustrated in Figure 8, claimed efficacies for LED linear replacement lamps rival their fluorescent counterparts. However, as predicted by their relatively low light outputs, measured efficacies for the LED products were considerably lower than for the fluorescent benchmarks.
Both linear fluorescent products were found to have accurate product information regarding efficacy. All four LED linear replacement lamps were found to have inaccurate or misleading manufacturer information regarding their efficacy."
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Re: LED lights, marketing vs. reality

Postby Think Wise » Sun Mar 13, 2011 9:12 pm

Although I didn't really mean this to be an argument. I have various independent tests showing otherwise. The two references above for luminaire output. 2xt5=3000lm and 2xt8 LED=3200lm are both NATA certified which is a lot harder to argue with than a 2009 report.

I am happy to pass on the reports.
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Re: LED lights, marketing vs. reality

Postby zzsstt » Mon Mar 14, 2011 6:35 am

"Independent tests" are carried out on whatever the testing agency is supplied - I have been involved with such things for many years! So if a manufacturer hand picks their samples (as most do) they can ensure the best possible result, both positive from their own product and negative from the "opposition".

As a consequence of this I tend to believe a government sponsored "round up" test of items taken from the market place is more likely to reflect the truth than a manufacturers own testing, no matter how independent the agency actually doing the measurements.

I have no doubt that the LED's tested in the report I quoted had "independent test results" included in their marketing, and yet the report stated "All four LED linear replacement lamps were found to have inaccurate or misleading manufacturer information regarding their efficacy."

However, I am perfectly willing to test the items myself. I would propose that I measure the light intensity at workbench height in one of my (windowless) workshops, illuminated by an exisiting fluoro light fitting (an inexpensive standard fitting that has been in place for about 4 years). I would then replace the tubes with LED's, making no other changes (except removal of the ballast/starter if required) or attempts to clean anything, and then re-measure the light intensity. Measurements would be taken at preset points to gain an idea of the relative spreads of light. For both tests the power consumption of the units would be recorded.

Of course such testing would not answer any questions about the products longevity, nor (if carried out on supplier selected samples) would it avoid the issues of above average "gold sample" testing. However if the results were as good as advertised I would repeat the tests on an anonymously purchased (and therefore "market sample") set of LED's.

I have a group of small retailers who are very interested in reducing their energy costs, which is why I have been looking at such products. If they tested well, I am quite sure that these people would be interested. Additionally the results posted on this site may well convince others!
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Re: LED lights, marketing vs. reality

Postby mikelowe » Tue Mar 22, 2011 4:45 pm

I'd be happy to supply you with a couple of LED tubes to test on a loan basis. I have looked into a lot of different suppliers over the last year, and there is certainly a lot of variation. Most tubes have a nominal 120 degree beam angle, which can lead to dark areas in between light fittings when replacing fluorescent tubes. To get around this, some tubes how have rotating end-caps so that when they are in pairs they can be angled to point in slightly different directions. I have also found some tubes which have a 150 degree beam angle. Send me an message on mike [at] powerupgreen dot com dot au if you are interested. (I don't want to attract spam by writing the address normally)
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Re: LED lights, marketing vs. reality

Postby Think Wise » Tue Mar 22, 2011 5:29 pm

What independent testing do you have? NATA, lighting council etc.
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Re: LED lights, marketing vs. reality

Postby mikelowe » Tue Mar 22, 2011 6:33 pm

No independent testing, just our own empirical observations comparing various LED tubes and fluorescent tubes in standardised conditions using a light meter at various distances and angles.
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Re: LED lights, marketing vs. reality

Postby karlajensen » Wed Mar 30, 2011 4:54 pm

I've just finished swapping out 50W 12V halogens for GU10 fittings and 5W LED's.
90% reduction in power use for 10% reduction in light output -est

The light output for the room is AOK -when they were probably too bright before.
Cost was $90 including the GU10 pigtails.

I'm tempted to do more now, the instant startup is great
Kids rooms have CFL lamps that take eons to warm up :|
and hallway would be nice to throw the two 5W CFL from either end and replace with downlights
as I think they will be sufficient light and the existing fittings are crap.
8E + 8W + 8Nth Garage CMS2000-1 with ~4500W in 3 strings of 8.
Fronius Galvo 3.0 inverter with ~6.6kW panels
12x ZNShine + 12x 180W Solarfuns both NW + ZNShine 12x190 facing SE.
Edwards Solar Hot water


Luck Favours the well prepared.
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