U.S. Department of Energy - Energy Efficiency and Renewable Energy
Building Technologies Office – Information Resources
Text-Alternative Version: LEDs for Interior Office Applications
Below is the text-alternative version of the LEDs for Interior Office Applications webcast, held March 18, 2010.
Terry Shoemaker: Welcome, ladies and gentlemen. I'm Terry Shoemaker with the Pacific Northwest National Laboratory, and I'd like to welcome to you to today's webcast, "LEDs for Interior Office Applications." This is brought to you by the U.S. Department of Energy Solid-State Lighting Program.
Today's webcast, brought to you by the Department of Energy's Technical Information Network for Solid-State Lighting, will compare LED and florescent technologies for office lighting applications.
The webcast will be presented by Jason Tuenge and Michael Myer, both of Pacific Northwest National Laboratory. Jason Tuenge joined PNNL in 2008 and has 10 years of experience in the lighting industry. He provides lighting engineering support for DOE activities within the commercial building initiative and the market-based programs for solid-state lighting. Jason received his BS in architectural engineering, lighting emphasis from the University of Colorado at Boulder. He is lighting certified and a LEED-accredited professional. Michael Myer has been with PNNL just under three years. Prior to joining PNNL, Michael worked as an architectural lighting designer. Since joining PNNL, Michael has worked on the Solid-State Lighting Team, including GATEWAY Demonstrations, TINSSL, and CALiPER. Outside of the Solid-State Lighting Team, Michael is an active member of the Lighting Subcommittee for the Commercial Building Energy Alliances. When he's not busy with those programs, Michael spends his time working on federal lighting efficiency standards in DOE's Appliance Standards Rulemaking Program.
The webcast today will focus on performance and economic considerations in replacing either four-foot TA lamps or entire troffer-type luminaires with LED products. Manufacturer-performed claims will also be compared against test results from DOE's CALiPER Program.
Jason, please take it away.
Jason Tuenge: Many of you have seen, I'm sure, a number of performance claims, some of them very wild, some of them very sneaky. This is one file that we have come across in reviewing some solid-state luminaires and lamps for office lighting applications like T8 lamps, T8 replacement lamps that is, and recessed troffers. Here's an IES file that may seem something that's actually valid. Just being an IES file, you assume comes from a laboratory. But just in looking at the first three lines of this file, you can see that there is some question as to whether it's really valid.
This next image comes from another manufacturer from their website. We've all seen before and after shots of the—basically the aesthetic benefits of LED lighting, and this one was a little bit curious because the before shot didn't even have any lighting.
The Department of Energy, depending on who you ask, is either a cheerleader for solid-state lighting or more like a policeman trying to rein in the various suspect manufacturers out there. The Department of Energy has developed several market-based programs to help guide the industry along, so really it serves as both. It's trying to help tame the wild west that is LED and, at the same time, help guide the technology along to get it adopted responsibly where appropriate. The two programs that we'll be focusing on today are the CALiPER Program and TINSSL, this webcast being brought to you by TINSSL and the CALiPER Program having already evaluated a number of products in the way of T8 replacement lamps or recessed troffers.
In January of 2009, CALiPER released a Benchmark Report for T12 and T8 replacement lamps and basically setting baseline performance for these products and also the luminaires in which they're installed, troffers like lensed troffers or parabolic louver troffers. This incorporates data from Round 9 of CALiPER testing or, I'm sorry, Round 5 of CALiPER testing.
The Benchmark Report summarizes the predominant technologies existing out there currently. There are still T12 lamps out there, probably more than we'd like to think, and then clearly a number of T8 lamps. That's really what sets the standard currently. A number of different ballast types and also discusses items like ballast factor as distinct from power factor.
So as far the luminaire type goes, like I mentioned before, we've got lensed and parabolic representing the bulk of what's out there. There are some other styles that have been introduced more recently, and we'll discuss those a little bit later. But mostly what you see out there are 2-by-4 luminaires and you also see some 2-by-2s and 1-by-4s and distributions for these or represented distributions for these are shown over on the right. It also discusses some basic considerations for deciding which type of luminaire you want and how much output you're going to need, for instance. So some factors here are, again, output, so that you get a sense of how much light you're going to have on your workplane. You need to pay attention to the total power draw if you're going to be paying attention to energy savings. And as far as, again, luminaire selection is concerned, you want to know the distribution so that you know whether you need to really control high angle brightness in terms of glare and reflected images off your computer monitor.
For the Benchmark Report, a number of IES files were evaluated for parabolic louver troffers, and one luminaire was selected for testing. In testing this luminaire, they took the standard T8 fluorescent lamp and electronic ballast and tested it that way, also tested the lamp on its own outside of the luminaire, so bare-lamp testing, and then did the same thing using a number of LED replacement lamps, and they did the same thing for 2-by-4 lensed troffers, except using a T12 lamp. And in this case, no IES files were surveyed. It was just simply tested with the different configurations of fluorescent and LED lamps.
The results of the baseline testing, so just looking at the louver troffer with T8 lamp and the lensed troffer with T12, just to show that the—that this—these samples were representative of what's out there, tables like this were produced in their report. I encourage you to go and review the report. It's posted online. A link is provided down in the bottom right corner of this page that will steer you to all these various programs, including CALiPER, and you'll find these reports there. You can see here though quickly that the claimed efficiency for this parabolic troffer was actually quite a bit higher than what we actually found in testing. The lensed troffer also had higher rated efficiency, but the difference wasn't quite as dramatic.
In looking at just the bare-lamp testing, so the lamps outside of luminaires, the rated lumens for the fluorescent lamps was actually right on target, and the SSL lamps or the LED replacements lamps weren't wildly off target except for one of the samples which was more than double what we actually measured.
The difference becomes more dramatic when you look at system efficacy. Again, the fluorescent lamps, the ratings were right on target. But if you look at the rated system efficacy for the LED products, the lumens output divided by the watts input to the system, the claims were consistently above what we actually measured, and in some cases quite significantly off.
Then looking at all of these lamps installed in the luminaires, we found that among other things that if you've got a solid-state LED replacement lamp that actually operates off of the existing ballast as opposed to removing the existing fluorescent ballast and using just the driver for the LED replacement lamp, you're not really sure what's going to happen in terms of your power consumption. It's going to vary depending on your ballast. And this really throws off calculations and predictions, so this is something clarified in the report and basically fair warning to buyers that you really need to watch this because it is difficult to predict your actual power consumption using LED replacement lamps on existing fluorescent ballasts.
To summarize the findings, basically the—while efficiency did increase after the fluorescent lamps were replaced with LED, this was relatively a small benefit compared to the drop in overall luminaire efficacy. So the total output of the fixture now divided by the input to the fixture, this dropped by a substantial margin more than the efficiency gain and so the net effect is that this was not a beneficial retrofit. Your output decreased substantially and your input watts decreased only a little bit. Same thing went for the lensed and parabolic louver troffers.
So some of you might be asking yourselves right now—So why… This is not consistent with what my sales person had told me and doesn't really stand to initial common sense. Basically a fluorescent lamp should have more light trapped up in the fixture because it's lighting all directions, whereas the LED lamps are automatically directional and directing their light out of the fixture. The problem is that this, again, does not overcome the losses inside the fixture. One of these things that's not be accounted for just through common sense is the thermal impact on the lamp. The lamps will operate at a higher temperature inside the fixture and so they won't be quite optimal, plus there are losses within the fixture still, and so this is not enough overcome a significant difference in output. Also, your distribution's going to be impacted because the parabolic louvers, especially in the case of the parabolic louver troffers, the parabolic louvers act as reflectors, and those reflectors clearly were not designed for this distribution coming out of an LED source.
This chart summarizes the results. Basically increasing luminaire efficacy going to the right and output going up, so basically you want to be in the top right corner of this chart. This is where you find the fluorescent products, whereas the solid-state lighting products are all on the bottom left. They do approach the T12 luminaire efficacy, but they fall well short of out—in terms of output.
Looking at the bare-lamps, a couple of them did not do well in terms of correlated color temperature. One of them would be strikingly blue in appearance, well outside of ANSI standards or ANSI NEMA standards for white lamp, and then another one also falls outside of this range, above basically the color of daylight. Power factor varied widely from being perfectly fine to being down to a 0.5 power factor.
For more information on the ANSI NEMA standard, see the standard C78.377. You can download this online from their Web site. Color Rendering Index is something that has come under fire recently for not accurately representing viewers' opinions of these sources, especially in terms of saturation or saturated colors, which can be rendered quite well by LED while still getting a low CRI rating. NIST has developed a new metric called the "Color Quality Scale." It's still under development. Again, you can find information on this on their Web site. One last item with these luminaires was discussed was workplane uniformity. Again, if your distribution is being impacted, if it's being focused, you can have reduced uniformity. One other thing to consider is that you can end up with some odd shadowing on your walls as a result of a retrofit in which you're changing your distribution, so this may be an aesthetic issue.
These diagrams illustrate this effect. Whereas on the left with a lensed troffer, the effect is not all that pronounced. There's a slight focusing of the distribution in general. On the right, we show a parabolic louver, and here you can see very clearly that the distribution has been utterly changed from a wide distribution to more of a focused distribution. This is something that many surely not expect and would likely be undesirable.
So again, we see this effect in looking at spacing criteria that are calculated for each of these luminaires, and so you can see it more clearly for the parabolic louver troffers. Again, those reflectors were not designed for this different distribution and you get some dramatic focusing.
So basically the toughest thing for LED to compete with in terms of fluorescent products is going to be a 2-by-4 lensed T8. These products are the most efficacious that you're going to find out there. When you look at a parabolic louver, you're going to have some losses internally, and the same thing it goes for 1-by-4 troffers or 2-by-4 troffers. There are some other products that we have not discussed here, white-painted louvered products can be popular as well. One that you're seeing in widespread use now is basket style indirect and another is lensed non-planar, so you don't just have a single lens covering the whole aperture. You have more of kind of an architecturally structured product with one or more luminous surfaces.
One major difference that you'll find between integrated products where you've got not a replacement lamp installed in an existing fixture, but an entire replacement of a luminaire is that these integrated products do a better job, have more room for materials to do thermal management. This helps in terms of lumen maintenance and color maintenance. You just got more space for your components. Another thing is that you don't have anything existing that's not known by the manufacturer, can't be known by the LED manufacturer in advance, interfering with your distribution.
So as mentioned before, the Benchmark Report drew on data from Round 5. Round 7 was published about the same time as the Benchmark Report, and in this another 2-by-2 troffer was tested. Then in Round 9, which came in October 2009, some more LED 2-by-2 troffers were tested. And additionally, we looked at some more 2-by-2 fluorescent benchmarks, one parabolic/one lensed, and did a number of bare-lamp tests looking at seven more LED replacement lamps installed in a parabolic troffer, as well as bare-lamp, and then looked at one more 2-by-4 fluorescent product lensed to get a sense of baseline performance.
Basically looking at the results saw that CCT was pretty good for the most part and that color-rendering was not necessarily optimal.
Also found in looking back at previous testing and these new products that the—again there are problems with LED replacement lamps that utilize the existing fluorescent ballast. Another one now is that the efficacy of the system tends to be lower when you go this route. It's better in general if you're going to go this direction to go with something with an integral driver. Again, efficacy was overstated for these products, output was overstated, and power factor ranged quite a bit from being problematic to being just fine.
So looking at the impact of replacing fluorescent lamps with LED replacement lamps in a parabolic troffer for Round 9 found that efficiency again increased slightly, but efficacy decreased substantially, basically overcoming this benefit once again, and output also again decreased; and we actually had a product where the input watts increased as a result of retrofitting to LED, which is probably not something that would be desirable.
This diagram shows again basically the efficiency for these various products, and in this case you again want to be in the top right. So at the top of the diagram, we're finding all of our fluorescent benchmarks and below we're finding all of our LED replacement lamps basically performing poorly when installed in these troffers. Looking at the integrated 2-by-2 LED luminaires as opposed to replacement lamps installed in existing troffers, we see again that the integrated products performed pretty well. We do find some overstated claims, but we find overstated claims for both fluorescent and LED, and in one case actually have LED being understated in terms of performance.
So again, output was typically overstated by a fair amount. Efficacy tended to be overstated as well, and power factor was pretty good for all these integrated products. One product did not have color fidelity within the criteria defined by NEMA.
But as we can see from this diagram as compared to the previous one for LED replacement lamps, the integrated products do a lot better in terms of efficacy. Here we're seeing that they're approaching the output of the fluorescent products and actually surpassing some of them and competing with all of them in terms of efficacy. So basically again, the integrated products do show promise for competitiveness in terms of output and efficacy, whereas the replacement lamps aren't doing so well.
Mentioned before, the impact on distribution, but so far we've really just been looking at more abstract terms and quantities. Here we've generated some pseudo color-renderings to help illustrate the point. If you've got an existing lensed troffer, your space is going to look something like this where you've got light fairly high up on the wall. Depending on your spacing, you'll have reasonable power density and good light levels with good uniformity.
Those familiar with parabolics know that they tend to produce less light higher up on the walls. This is basically the side effect of trying to reduce images produced on monitors, but notice that power density and light levels are still looking pretty good.
If you were to replace the lensed troffer with an LED replacement—or if you replace the lamps in a lensed troffer with LED, then your result would be something like this where light levels drop by a larger proportion than your power density, so your energy savings was a direct result of a reduction in light levels. You could have achieved the same result just by going with lower wattage fluorescent.
And again, if you replace the fluorescent lamps in a 2-by-4 parabolic louver troffer with LED, then you get the same result. Again, you get more light loss than you do energy savings, so not a really good option.
If you replace instead with 2-by-2 LED integrated products, then you don't get as much reduction in your output and you do get some energy savings, so this might be something to consider as being competitive with an energy savings option in terms of fluorescent. Here LED would compete with a fluorescent retrofit, but wouldn't necessarily outperform fluorescent in this case either.
And then this gives you a sense of if you were to try to go from a 2-by-4 to a 2-by-2 fluorescent for energy savings, you get a very similar effect. You don't get as much energy savings in this case, but you get slightly higher light levels versus the LED, but notice the difference in distribution and the effects on the walls.
So still really fluorescent is probably your best option for replacements of this sort. Here we're showing benchmark troffer, high performance giving us energy savings and maintaining output.
We went ahead outside of CALiPER reporting to date and did another survey, this time for LED replacement lamps to get a sense of where the claims are currently versus what's been tested, and you can see here that basically while there are a couple of claims that were singled out by CALiPER and proven not to perform on par with T8, everything else is low in terms of efficacy and output.
And then looking at integrated troffers, we find that they're doing much better. That they don't necessarily outperform fluorescent, but they are competitive.
One thing to note is that all the data discussed thus far has been for initial performance. One big question mark for LED right now is maintaining performance. CALiPER did perform some testing to see what we might be up against in terms of early premature degradation of performance and found that while some products do quite well and basically do not degrade at all, others dive immediately in terms of output and fail after a thousand hours of operation or slightly more. Unfortunately, this covers a broad range of product types, including MR16 products, replacement lamps, PAR replacement lamps, and other fixture types or and then other luminaire types I should say. Unfortunately, the only product out of our set that we're looking at now, T8 replacement lamps and integrated troffers, only one was tested, and I've indicated it here to show that this product would actually drop to 70% of initial output after just 6,000 hours of operation, well short of what might've been claimed more in the neighborhood of 50,000 hours.
So again, performance varies widely. Some of these will likely do fine, but others may be problematic.
So basically make sure to check RP-1 to make sure that you're considering all the factors we've discussed thus far and some additional issues. One thing I touched on earlier was color maintenance. There has been a lot of attention to lumen maintenance, not as much on color maintenance, but this is also an issue. You don't want too much color shift happening over time either. This may be addressed by the TM-21 Committee working on lumen maintenance. There is a document that may be of interest to discuss basically compatibility with dimming controls. This is more… This is intended for incandescent replacement products, but will cover many issues of interest. This is available online. The link is given here. IEEE has released a draft standard addressing flicker. This is probably also going to be of interest. And again, the draft document's available online. And last, make sure that when you are considering these retrofits, that you're watching safety. That you're making sure, for example, that any UL listing is maintained after the work is done.
When you're looking at the economics for the project, make sure to look at the cost to purchase and install, the cost to operate, and the cost to replace and dispose, in other words the complete lifecycle of the product, of the retrofit. So for purchasing and installing, make sure to talk to a contractor to get a good estimate of the labor involved and make sure that the contractor understands what exactly is going to be involved in this retrofit. So other factors include the total load, the operating schedule of the luminaires, electricity rates, how often are these things going to be maintained. They will likely need to be cleaned and they might need a driver replacement somewhere along the line, and again there are issues with rated life. Make sure that you've got something covering lumen maintenance in terms of performance.
With that, I will hand it over to Michael.
Michael Myer: Thanks, Jason. So I'm going to focus on more of the actual integrated luminaires rather than the replacement lamps. The first slide you're now seeing on my portion is just a step back into looking at lamp lumen depreciation. We know that as sources operate, they diminish over time in how much light they put out. This is an expediential graph with an expediential function. So on the X-axis, it's from a thousand hours to roughly about 80,000 hours; and on the Y-axis, you're seeing initial light output normalized to 100%. Because it's looking at a log rhythmic base in the X-axis it's very truncated. We're seeing a lot of information in the first thousand hours and then the later mini thousand hours, 10 to 20,000 hours, it's truncated very quickly, mainly to show how the LED will perform when purchase L70. This is a comparison of there are fluorescent technologies out there that can last 24,000 hours or 36,000 hours or even 42,000 hours depending on the switching combination and the type of ballast, and so what we're seeing for the most part is that over time that fluorescent technology is going to diminish from about 100% to worse case about 90% and then have to be replaced. That's a quick jump up back to 100%, and then the downgrade back again. Whereas the LED product was going to slowly degrade, keep degrading, and then kind of fall off to this L70, this 70% of rated life. So it's something to think about as we start moving forward in design whether it's a dedicated LED or a luminaire or a fluorescent, the lumen maintenance is a very important issue that needs to be factored in, not just the initial, but the long-term values.
This is a slide I came across of some information of a dedicated 2-by-4 product. It is advertised as being an equivalent or can replace a three-lamp T8 fixture. And as I went through it, it's only producing about 3,000—3,400 roughly lumens from the entire luminaire. It cost almost $800, which is very different from most fluorescent luminaires that I'm used to; and so when I did the math, just divided by the number of lumens divided by the cost, it comes out to about $4 per lumen.
And so I also looked on the site for what a fluorescent product costs just to get a sense of what the market was like and I found this slide where the—this is just again a standard fluorescent product. Its three-lamps, just run of the mill, it cost less than a hundred dollars; and it produces about almost 7,000 lumens, which is what we'd expect. And if you again just do the simple math of the number of lumens divided by the price, you see that it's about 77 lumens per dollar, much better than the four lumens per dollar that we saw in the previous slide. So cost is still such a major issue and also the number of lumens you're getting for the price is something to be factored in when we start looking at dedicated luminaires.
Another product I found, this is a replacement kit. It's slightly different than the products Jason was describing of LED tubes that are meant to mimic the fluorescent lamp, this is essentially a housing kit where you pull out the gut of the existing product and you install this in its place. The manufacturer claims about a 10/20-minute installation process and the kit itself has LEDs in it, so you're getting your dedicated optical system. So it's different than what Jason is describing, but it is not entirely a whole new luminaire. Again, it's about $600; and when I did the math from the number of lumens provided from it for the price, it was about 6.5 lumens per dollar. Again, the fluorescent system is much cheaper, as well as energy efficient, so it's interesting just to see the cost out there and the amount of products that are coming out.
In addition to looking at 2-by-4s, we've done a very extensive examination of 2-by-2s. As Jason mentioned in previous slides, that the 2-by-2 performance is very interesting is actually approaching… I'm sorry, the dedicated LED 2-by-2 performance is actually approaching the fluorescent 2-by-2. So in the process of developing some of that data for CALiPER, we actually looked at: Well what are the conventional—what's some of the data about conventional 2-by-2s? So the following slides are going to be comparison of those products. So for a lensed 2-by-2, the efficiency ranged from about 64 to 89%. It's pretty hard to get much above 89% just from the sheer physics of light passing through a lens, you have to have a really high performance lens to really eke out any few more percents, percentiles of efficiency. Typical lamps in a 2-by-2 lens are the two-feet T5, either the normal T5 or the high output T5. Two-feet T8, which is the F17T8, or the linear biax, which is the F40 or the F55, or possibly the T8 bent lamp, which is the F32, it's also a 31 watt lamp, we're all familiar with that one as well, the lens diffuses the lamp image. K12 is a typical-type diffuser. Finding data on 2-by-2 distribution of sales was not relatively and easy, but from my previous years in design, as well as speaking with other people, we kind of felt that lensed 2-by-2s represents a portion of installed 2-by-2s, but not a major portion.
Moving on to another type of luminaire, this is the conventional parabolic 2-by-2. Again, we found that a general range for these products was about 51 to 72% efficiency, so best case about 30% of the light is not leaving the fixture, worst case 50% of the light is not leaving the fixture, so that's an impediment to this technology. Jason kind of did a good job or describing the benefits of the louver and what it's doing, so we understand why we're taking the efficiency losses, but that's just the matter of fact it is. Again, the lamps here are very similar to the previous lamps I mentioned. The idea is that you put a lamp in the center of the cell over the cell, not always, but that's the idea. It's slightly different for U-shaped lamps. The cell combination comes and can vary. It could be as few as four cells to up to as many as 64 cells. Again based the data from my experience and others, we felt that this was the majority of installed 2-by-2s. Again, we had no hard data, it was more subjective beliefs.
Moving on to a newer type of luminaire that was designed and gained more traction in the late '90s, this is the indirect/direct 2-by-2, also referred to as the basket. The bottom image here really kind of emphasizes why it's called a basket fixture. These vary widely in performance from as a little as efficiency of 33% to as wide or as great as 79%. That's a very large range. The lamping here of course because of the design and your smaller optical places for lamps, you can't use the U-lamps in these type fixtures. Typically they use either the linear T5 or T8 or the 1540 watt Biax. In the top image above, you'd have one lamp under each basket. In the center, in the bottom image, you'd have just one or possibly two in the center as well. There are… They're typically made of perforated metal. They can be side mounted or they can be center mounted. Sometimes they drop below the ceiling plane or sometimes they're in the ceiling plane. This represents a small portion of the installed. We believe this represents a small portion of the installed 2-by-2 market.
And the final type of 2-by-2 we came across, and this is a much newer type of fixture, is what Jason mentioned earlier was this non-planar-lensed fixture. It's important to differentiate between the planar-lensed fixtures and the non-planar-lensed fixtures in that the manufacturers are designing these fixtures to do more. They're actually designing the optics in the lens around the lamp rather than just being very flat, you're getting more benefit by having it angled or a curved lens designed around the lamp. That's reflected in efficiency ranging from 67 to 90%. Here the lamping is primarily T5, but—and you can have some linear T8. Because of the optical design of the lens here, you wouldn't want a large source like the Biax and definitely couldn't use the U-lamp. The lamp is obviously in the center of the chamber, center of the lens essentially. You could have one to two lamps and lenses per fixture. It varies. This is a rather relatively new type of luminaire, that's why it's a very small portion of the installed 2-by-2 market.
So Jason touched on some CALiPER data, and this is a comparison of LED dedicated 2-by-2s, which is the five columns—or excuse me, five rows and then two fluorescent luminaires as well, and the CALiPER numbers are there in case you want to go back and look at CALiPER Report and read more information about the products. Their input powers varied from as few watts as 36 to up 75 watts. Light output also varied. Luminaire efficacy is very interesting. Of course this is initial efficacy, but you'll notice for the fluorescent, they were both in the mid—mid to high 40s. If you look at most of the LED products, the efficacy approached and in some cases surpassed. There is one standout efficacy product of 79 lumens per watt there, which was vastly better than the fluorescent products. We'll discuss more of these luminaires in the following slides.
As I mentioned in those previous slides about the conventional products, we surveyed roughly 200 IES files and manufacturers' data about the efficiency of their products, and that's how we generated some of that information. We put together an Excel spreadsheet where it multiplied the efficiency of the fixture by the lamp ballast efficacy to generate some of this information, so this is information about CALiPER 09-81. On the right, you see the image of what the fixture looks like. On the bottom, you see the distribution. It's pretty much cosigned distribution. It produced about 2,600 lumens. And as I mentioned, we surveyed 200 products, mostly through mathematical calculation, but we found that based on those calculations, this product produced more light than 121 of those. In terms of luminaire efficacy, it was about 41 lumens per watt, and of those 200 products that we surveyed, only 45 had higher efficacy. So that's trying to put an idea of where this ranges—ranks compared to some of the conventional products.
Again staying with the format, this is for CALiPER 08-29, you have the image in the upper right-hand, very similar distribution to the previous slide. You'll see most of the distributions for the LED products are very similar in that they vary cosigned distribution. This product produced, again, a fair amount of lumens, about 3,500 lumens, and efficacy was around 46 lumens per watt and only 45 products were more efficacious than this.
Continuing into 09-71, again you have the image. Notice how they're very similar looking in images as well. Just because the way the LEDs are designed, I think most manufacturers are finding it easier to do a piece of optical material to diffuse the image, and that's also why we're getting some of these cosigned distributions. Again, pretty efficient product producing a fair amount of light. We'll see in a couple of slides how these graphically relate to each other as well.
Moving on to again this is another CALiPER report, 08-134. It only produced 2,100 lumens. That's kind of at a low point, and there was only 36 products that actually produced less lumens than this, but its efficacy was pretty good, so it's a trade-off type of thing, and so that it was 50 lumens per watt and only 33 conventional products had a higher efficacy. Notice how the distribution here is slightly different than the previous distributions, but not too different.
Moving into our final LED 2-by-2 that we reviewed from CALiPER 09-41, the image on the top again. Notice the distribution here is again mostly cosigned in distribution, but is very narrow. It's very shaped, and we'll talk about what distribution, how the distribution compare in a little bit as well, produced about 3,200 lumens, which is in the middle in terms of middle to high in terms of overall light output. Efficacy though, as I mentioned earlier, very efficacious and only two products had higher efficacy than this luminaire.
As I mentioned just briefly, there—we see graphically how we compared all this data. So here's a comparison of initial luminaire output and initial efficacy. So on the X-axis, its initial luminaire output in lumens from zero to 10,000 lumens. On the Y-axis, we're looking at luminaire efficacy or luminaire efficacy rating, which is what LER stands for, expressed in lumens per watt ranging from zero up to 120. The square… I'm sorry, they're diamonds and they're the darker colored, that's the conventional catalog data. And essentially, as I mentioned earlier, we created an Excel spreadsheet of the efficiency of the conventional fixture times the applicable lamp ballast combination and that's how we got both the output as well as the efficacy. It's based on catalog data only. The lighter colored squares is the LED catalog data, and the triangles are the CALiPER tested LED data. So you'll notice how in some cases the triangle doesn't actually differ too much sometimes from the square, but you'll see right now, as I mentioned in the previous slides, where all these compare. So in terms of efficacy, most of the products are high compared to the conventional. And in terms of initial light output, they rank in the med.
Moving on to what's going to happen over time, this next slide is looking at mean output to luminaire efficacy. So again on the X-axis, we're looking at luminaire output. In this case, we tried to look at mean luminaire output. For mean lumens for the conventional technology, we just took the catalog data with the mean lumen value they presented, which for us and for most manufacturers tends to be at about 40% of rated life. For the LEDs, we picked L85, meaning we assumed the halfway point between L—between full light out—or initial light output and L70 and called it—and said LED, which is the L85 or 85% of initial light output. And again, on the Y-axis, you have the luminaire efficacy. Notice how the data has somewhat clustered and notice how the LED data is moving into the cluster and it is less standout compared to the fluorescent data.
Moving to the end-of-life efficacy, this is using L70 and a slightly extrapolated value for the conventional catalog data. As I mentioned earlier that for most of the fluorescent technology, the lumen depreciation is really going to go from a hundred to about 0.9, so that data hasn't moved that much. But for the LEDs, it's going to go from a hundred to 0.7, so it moves a fair amount. So while these LED products were somewhat standout in the beginning, they've moved much more into the center of the cluster of the conventional data.
I mentioned earlier we were going to discuss distribution. So this is just a sample distribution—photometric icon associated with each of the different luminaire types and their spacing criteria and then their efficacy. It's just really an overall idea slide. It's just representative. There's definitely products that are outliers in each of these categories, but it's meant just to show a sample. So for a lensed fixture, the spacing criterion is helped use the layout fixtures for uniformity, and we'll discuss that a little more later as well. The range is 1.18 to 1.26. I don't really want to focus too much on the range, but just going to show a sample, and the efficacy is about 65 lumens per watt for the lens. For the parabolic, because of the optical losses from the louver, you really are taking a hit, so you're at about 51 lumens per watt. Because of the perforated metal really being inefficient for the basket fixtures, you're really down there at 46 lumens per watt. But again, the non-planar tends to use a specialized optical system and so their efficacy is back up near the lens—the planar lens efficacy at about 62 lumens per watt. Notice how the distributions for the four fixtures varied. The lensed and the non-planar are similar, but they're slightly different.
Moving on into the next slide, this is comparison of the conventional products on the top and the LED products on the bottom. Again, as I mentioned earlier, the LED products all had relatively similar, and I said they were pretty much cosigned distributions, so if you look down the bottom, we were able to collapse 09-81/08-29. Really the distributions were very similar. The outputs were different, but we're not really looking at this in terms of intensity. We're just trying to get a sense of distribution. So notice how the LED distributions were all very down, as I keep saying cosigned. Now compared to the distributions on the top, parabolic is very different. The basket is very different. So these distributions are very similar to either the lens or the non-planar-lensed for the LEDs versus the conventional distributions.
Continuing on, as I mentioned, we'll discuss spacing criteria in a little more. So again, spacing criterion helps you lay out fixtures for uniformity and coverage, and you multiple the number by the mounting height. So if you're putting this on a nine-foot ceiling, you would multiple, your spacing roughly would be nine times 1.3 and you'd get somewhere around 11.7. You could round up to 12, and that would tell you—help you layout some of your spacing. What's interesting to look at the distributions here is notice how a number of the LED products had similar spacing criterion, but 09-41, that was the one with the more shaped somewhat narrow distribution, how the spacing criterion is much lower here and it's how it's lower than both of the fluorescent products. So that's just a sample to show how the spacing criterions for the different products compare to each other.
So moving beyond spacing criterion into glarish [sic] metric, and I say "glarish" because there's many different glare metrics, but RP-1, which is the IES document, the recommended practice for office lighting was published in 2004 with new metrics. They recommend that a luminaire have limits on the intensity at certain vertical angles for VDT, and VDT is the visual display terminal, dates back from a term from the '80s, but it really just means computers. So if your very computer intensive work, it's called VDTI; and it's VDTN, it's just normal. I think most of us fall within normal range now. Years ago, this was a very big issue and there was the cathode ray tubes where we had the big monitors, the black screens, and you could get the reflection from the fixture above causing glare. Now that we have much better performing monitors, this has become less of an issue. However as high def has come out, has become a new technology and people are moving towards it, it's now an issue again. So it's just funny how this all comes in cycles. It's also… It's a way of trying to limit glare without having to do with a lot of the geometry issues. So RP-1 just says at 55 degrees, at 65 degrees, at 75 degrees, and 85 degrees, the fixture should not produce more intensity than the specific values presented in the top two rows. So for VDT Normal, I'm just going to walk quickly through those values, at 65 degrees vertical, it shouldn't produce more than 300 candelas. At 75 degrees, it shouldn't produce no more than 185 degrees. And at 85 degrees, should produce no more than candelas. I took a little bit of a liberal interpretation. Notice at the bottom, you'll see an asterisk. It says VDT compliance. I kind of led in anything that was within 10% of the limit if it only occurred in one vertical angle. For instance… And we'll walk through that in a second. These are also based on the average across all the different horizontal angles measured, so when we do photometry, we might measure in the zero plane and the 45 plane and the 90 plane, and there's actually even more planes, but those are pretty typical for a troffer plane. I didn't want to come up with a huge spreadsheet of looking at every one, so I just averaged the—all the different horizontal planes into one value, and that's what we're seeing here. So I as I mentioned, so we're just kind of walk through it. So if you look at, let's pick one, the top one is an easy example, 09-81, the first, at 55 degrees, it's well over 300 candelas, so 09-81 would not be an VDT intensive product. So then looks at it for VDT Normal, well we see that it's output is 332 candelas and VDT Normal sets it at 300 candelas. That's pretty much 10% over, and I kind of said, "OK, it kind of works." At 75 degrees, it's pretty much there; and at 85 degrees, it's just below. So this kind of walks through in terms of the LED products, 09-81 qualified as VDT Normal. 08-29, 09-71, neither of them would've meet either VDT requirements. 09—or I'm sorry, 08-134 actually meets both on VDT Intensive and VDT Normal when you use the 10% adder. 09-41 this is that distribution that's been narrow, neither of them—it wouldn't qualify in VDT—either definition of VDT. For the fluorescent, which is 09-72 and 09-73, 09-72 did for both VDTs and 09-73 did not for VTD Intensive. It's just a good way to see because we need to talk about other things besides efficacy and light output. Because if it's installed in the space and it's very glary or the uniformity's an issue, that's something that's going to be a design issue later on, and efficacy is just a start to good design. Glare and color and all those other metrics are very important and we should talk about them when possible.
Moving onto, as I said, a design, so I took the photometry of the IES files and I used the AGi room estimator. Mostly I just want to get a sense of how these would do in terms of an overall layout. I made up an imaginary room that was 120 feet by 45 feet with a nine-foot ceiling. This is all pretty standard formation. I asked for a 40 foot target—I'm sorry, 40 foot candle target illuminance, and then I picked light loss factors. I kind of said, "OK, they're all going to have a little depreciation, which is the LDD value." For the luminaire—the lumen depreciation value for fluorescent, I picked 0.92; and for LED, I picked 0.7, and then I'm going to step through what the data or summarized is in the next slide.
So on the left-hand column here, we have the different CALiPER Report associated with the IES file. The next column we have the number of luminaires. So the way the room estimator works is you put in your room, you put in your target illuminance; and based on the photometry of the file, it says, "OK, you need this many fixtures." So in this case, for the different fixtures, we need as few as 80 and as many as 160. It definitely shows how both efficacy and light output are factored in there. The next column just shows efficacy, kind of showing how it all works. The next column over shows what the illuminance was based on the number of fixtures. So the first one we needed 80 fixtures and it gave us 40 foot candles. The bottom one, we need 160 fixtures and we got roughly 40 foot candles, 39.6. The next column over is the LPD or the lighting power density. Mostly this is just showing that you if installed 80 of the first fixture, you'd have a power density of 0.95 watts per square foot. In the next slide, I'll show you how that relates to Standard 90.1, which also is shown over on the right-hand—the end column where whether or not it's Standard 90.1 compliant, which is an overarching energy code based on power density. And then the column in between that I just mentioned was dollars per square foot. I looked at the prices that was paid by—for the CALiPER Program, which are not representative prices, they're just the prices they paid. The prices are going to vary for every sight, both by location, quantity. There's so many factors in price. This is mostly meant to get a sense of magnitude of how price relates. So for the fluorescent systems, if you had designed this room accordingly, you would spend maybe as low as $5 a square foot to as high as $11 a square foot. In contrast if you designed the system, the space using the room estimator for the LED system, you could've spent as little as about almost $8 a square foot to as high as $18 a square foot just because for that one that's $18 square foot, you need 150 of those fixtures, and just that sheer number adds up after awhile.
Moving on to another summary slide. So this is kind of overall some of the ideas we talked about thus far on the different LED fixtures as well as the fluorescent fixtures. The first column, again, shows CALiPER Report. The second column is whether or not the design in the previous slide met the Standard 90.1 requirements. The next slide over shows what the power density was in relation to 90.1. I used a value of 1.1 watts a square foot. Depending on where you are located, your state may have adopted a different version of Standard 90 and you could possibly have more power density. This is just picking into relation to the current value. So for some of these designs, they were as low as 35% below Standard 90 to as high as 18% above the allowed power density in Standard 90. And efficacy factors into that and so in some of these cases, if you're marginally efficacious product, such as 46 lumens per watt, if you're not producing light, that's why your over in terms of your power density. So efficacy is an issue, but also overall light output is an issue. They're related to each other. But not just efficacy and light output are issues, we also, as I mentioned, player and this RP-1 compliance is something to be concerned about. So of those products, this is a repeat of what we saw earlier of some of those products do meet RP-1 and some of those products don't meet RP-1. And then the final slide is a dollar per kilolumen. That's a very different type of metric, but the LED world likes to think in the dollar per kilolumen metric. This not at the LED level. This at the overall luminaire level and so this just gives you a range of the idea of cost related to the different systems.
And then moving to kind of the future, the CALiPER and the TINSSL programs have new things coming out. Specifically there's going to be more benchmark reports and more—and CALiPER is continuing to test new products. They have a pretty three to four-month publication cycle, I believe, so there should be a new Round 10 coming out very shortly with new products. And they try to get the replacement lamps in there, not just the linear fluorescent, but also other types every round just because that's a growing market. They also look at other type of products, so that's always a great place. There's also upcoming fact sheets and a fact sheet is a dedicated number of pages, a few as two, as many as six, about a given topic. In this case, there's actual T8 replacement fact sheet coming out that will be of an aid as well.
And at that point, Jason and I are going to turn it over for questions.
Jeff McCullough: Good day, everyone. This is Jeff McCullough with the Pacific Northwest National Laboratory, and I will actually be administering the questions.
Before I do that, I'd like to make a couple of comments, and then we'll go to questions and answers. One thing that I'd like to report to everyone is that as a result of CALiPER testing, a major online lamp retailer has made the following statement: "After reviewing the CALiPER 9—I'm sorry, CALiPER Round 9 test results referenced in the following Postings," the Postings are from Jim Brodrick's online newsletter that's provided to members almost on a weekly basis, "the retailer has decided to discontinue our offering of LED replacement—T8 replacement lamps at this time." And the date is 1/7 of '10, so it's since January 7th of this year. "We will continue to monitor LED technology developments and revise our offerings at a later time if and when appropriate." The reason we bring this to your attention, as it's clear based on CALiPER testing, the information you now heard from both Michael and Jason, that we need to exercise due diligence with this technology, especially in this particular application. So I share that with you just to kind of make you aware that there's a lot of concern out there in the industry about the performance of these products and hence the reason why we're all gathered together here today.
So with that said, here's how we'd like to proceed. First of all, thank Jason and Michael for their time in presenting the material today. Thus far, we have received an excess of 60 questions, so there's certainly no way we can get through all of them. So what I will do, and I have all the questions in front of me, I will assign Jason and Michael various questions. And the way that I'll do this is I will read the question and then ask Jason and Michael to come and go ahead and respond to them. So please be patient. It's somewhat of an interesting process as the flood of questions come in to be able to decide which ones are most appropriate to the talk given today.
So with that said, the first questions will be directed towards Jason, and let me read them here first, and it goes back to one of his early slides. Why are the IES files suspect, and can you tell us how to evaluate the first three lines of the IES files? And so go ahead and take it away, Jason.
Jason Tuenge: All right, thanks, Jeff. Yeah, sorry for the mystery. That was… It wasn't deliberate. I didn't want to give away basically the secret to those manufacturers online and looking for quick fixes to problems as we find them. Basically the answer is to look at IES LM63. This describes the proper format of an IES file, and you can be sure that if you get an IES file from a test—from a qualified test laboratory, you're going to get a properly formatted file. So when you don't see a properly formatted file, it's kind of a hint that it's been either created from scratch or modified and improperly, so basically a warning flag should go up.
Jeff McCullough: Thank you, Jason. Let's do another question for Jason, and the question is relating to some of the test reports that were completed. If you didn't survey IES reports for T12 lensed troffers, how did you get their rated efficiency?
Jason Tuenge: Basically I would direct you to the—back to the CALiPER reports. It does give some more of this information there. As far as the T12 goes, basically one product was tested and one product, the cut sheet was evaluated and actually an IES file was obtained for that product. So it's an older product. You probably can't find that information online anymore, but they do have it still back at the factory. So you can go—basically you can go back to the detailed CALiPER reports and get more information.
Jeff McCullough: OK, thank you, Jason. One more question for Jason, and then I'll give Michael a couple. This question came at least two or three times with people asking: Please explain the difference between power factor and ballast factor.
Jason Tuenge: So this one is pretty tricky. Power factor, there's lots of discussion ongoing over power factor and how critical it is, and there are definitely various camps arguing whether it's really that important or not. We definitely pay attention to it. We believe power quality is important. Utilities will tend to agree. Basically power factor does apply to both LED and fluorescent, whereas ballast factor really only applies to fluorescent. The basic difference being that with power factor, you've got a difference—if you've got bad power factor, a low power factor, then you're going to have a difference between your watts and your VA. So basically you're going to be pulling more current than you think you're pulling and this can cause problems for the system, for the utility, and can influence your power quality in the system in general. Whereas ballast factor is really—the way to look at ballast factor, it's kind of a fixed dimming of a fluorescent lamp. And so if you go with the 0.88 ballast factor, then you're basically dimming your lamp to 88% of full output and you're doing so efficiently, so it's just kind of way you can also boost the output by going with like a 1.18 ballast factor. So it's something to pay attention to when you replacing fluorescent with LED because it's going to impact your output and your power consumed.
Jeff McCullough: Thank you, Jason. Let's give a Michael a chance to answer some questions. And so with that said, Michael, one question we'd like to ask you is: Where do we go to view the CALiPER Reports?
Michael Myer: Thanks, Jeff. I apologize we didn't provide that link. It's real easy, and this is where you'll find a lot of the Department of Energy Solid-State programs. First the URL is: www.ssl.energy.gov. That'll bring you to the main home page of the commercial programs for the Department of Energy, and you can find CALiPER there. Or if you want to bypass that, you just put a slash after the dot-gov and put CALiPER, C-A-L-I-P-E-R.html.
Jason Tuenge: And the main link was given at the bottom right corner of each of these slides.
Jeff McCullough: Thank you, Michael and Jason. Let's do another one with Michael. And, Michael, this question comes from your presentation where the numbers aren't matching, so the question is: The efficacy numbers he, meaning you, are quoting don't match the slides.
Michael Myer: Yes, I apologize for that as well. It's one of those things of writing a script and then after you wrote it, correcting the numbers in the slide and then not going back to correct the script when you gave it today. So the numbers in the slide are more accurate than what I read. As I mentioned, as I was writing the—reading the script, I caught the numbers and I corrected it, but I forgot to update my script for today, so I apologize. So these numbers, as I flash to the screen right now on your screens, are the more correct numbers.
Jeff McCullough: OK. Thank you, Michael. Let's give one more to Michael and then we'll go back to Jason. This one to you, Michael. When you say you tested 200 2-by-2s, does that include both conventional and LED products?
Michael Myer: Let me pull up that slide to what that's referring to. So first, I hope I didn't say the word tested. I meant to say what we did is we calculated and it was not conventional, so this graph is what that slide—that question is referring to. You're seeing… We took catalog data for the efficiency of a lamp fixture and put it into a spreadsheet—efficiency of a fixture, put into a spreadsheet, and then we came up with a lamp ballast combination for its efficacy. And if the manufacturer made a product that could use a two-foot T8, we used a representative two-foot T8 efficacy and multiplied it by the efficiency of the light fixture and that's how we got these efficacy numbers. So the 200 number—the 200 values were based on catalog data for conventional fixtures, and then any LED fixtures that we had were based on either the LED catalog data, which is the square in this slide, or the actual tested CALiPER data, which is somewhat slightly different usually than the catalog data, for the triangles, so that's the comparison. The bulk of the 200 data points are only conventional.
Jeff McCullough: OK, thank you. Let me put a question that I'll put back to Jason, but Michael welcome—is welcome to chime in as well. There's been a number of questions basically with folks asking: Where do I go to find good products and to learn what products perform well? So the question to Jason is: What resources are out there for lighting designers to be able to use to know what are good performing products and where do I get that information?
Jason Tuenge: Well the skilt [sic] of most of the work by DOE is really to just provide guidance in terms of evaluating products, not really for the most part providing a list of good manufacturers. You can just go and find the stuff that you want really quickly. So, for example, the Lighting Facts label, that's not necessarily giving you good products. That's just communicating clearly what these products should be producing for you when you buy them. ENERGY STAR, on the other hand, does have a threshold which you have to pass, but Energy Star categories don't exist for all products that are out there. So unfortunately, you're not going to be able to look to our resources from our main website and really find a complete listing across the board of quality products. It's really more geared to helping you differentiate between the good, the bad, and the ugly.
Jeff McCullough: OK, thank you, Jason. I'm going to follow-up with another question to Jason. This is a question where the respondent asked: In seeing actual installed LED tubes, obviously linear replacement tubes, in an office environment, we found a savings in watts of about 50 watts per four-tube fixture. The actual light output in some private offices was too bright and the LED tubes had to be reduced to two tubes per fixture. This does not appear to be consistent to what I think I'm hearing. Can you explain why we might see that?
Jason Tuenge: Unfortunately some of these questions are going to be coming from manufacturers most likely, so that's one thing to bear in mind as we answer some of these questions. They may not actually be from a customer. Basically there are two parts here. One is that CALiPER will lag products that are out there by a certain amount, timeframe. We cannot test products that are hitting the floor like the day they come out, so, yes, there will be a lag, and potentially there are some products out there that will perform at a level higher than what you're seeing tested in these reports. That said, basically what we're finding consistently is that the claims that you're seeing out there aren't holding water and that basically you'll continue to see claims of stellar performance and what's happening unfortunately is—and you may even see test reports showing really great performance. Unfortunately what can happen with some of these companies is they will basically submit a product that's on steroids frankly to make it look like all their products will be performing well, and then what you actually get is not what was actually tested. CALiPER basically is designed to catch this sort of thing. So even for products that have been independently tested and tested well, CALiPER will randomly select those without the knowledge of the manufacturer and then find that sure enough they're not performing as previously tested and claimed. So it's just something to keep in mind. It's impossible to truly capture exactly what's going on out there, but CALiPER is doing its best.
Jeff McCullough: Thank you, Jason. Let's shift back over to Michael for a few questions, and, Michael, these are some questions regarding your slides. Cost per square foot, is that for luminaires only or does it include design, installation, and controls?
Michael Myer: Thanks, Jeff. I'm going to try to advance to that slide. No, the costs were just—it was meant to be a representative cost to get a sense of where they were going. It does not include installation. But these are all individual units, so I would think that cost of labor would be relatively similar between a 2-by-2 LED and 2-by-2 fluorescent the amount of time that it would take. For safety reasons, you're going to have to tie-off to the same structure for both types of luminaires. It's not like converting from a 2-by-2 to linear fluorescent or linear unit where you have different installation costs. I would think that for single 2-by-2 units, the installation cost should be similar. It does not factor in controls either. It was meant to be a jumping off point.
Jeff McCullough: OK. Let's follow that one up with: Did you include installation costs in the final cost analysis presented?
Michael Myer: Yeah, I apologize for not providing all the caveats to the prices. No, it was just, again, the initial cost that CALiPER paid.
Jeff McCullough: OK. And one for Michael. You mentioned the CALiPER prices are CALiPER price. Are products tested by CALiPER commercially available only—commercially available product only? Also, 2-by-2 integrated luminaires tested higher in efficacy than—and they're referencing a specific test report of 09-41, at CCT were those luminaires?
Michael Myer: OK. Well the CALiPER prices, CALiPER is a program, so it's funny to refer to things as CALiPER prices. So CALiPER anonymously buys, and that's why we can't allow manufacturers to submit product directly to us. As Jason said, we're sometimes worried about hero products or products that may be performing slightly better than they could be or they're next generation products being dropped out early to make it—because of the time lag. So the way CALiPER buys products is that we have a pretty sophisticated network across the country buying products under different names and they actually buy—they go through distributors and they buy products. Sometimes, they buy them in large quantities and one comes to us and the other quantities are going somewhere else, but that's how it works. It's meant to represent stuff that anybody in the market could be getting right now. So that's why our prices are different; and most people in lighting know that the prices vary by region, by quantity and manufacturer in relationship to those people. So if you bought a fixture for New York City versus a fixture for Topeka, Kansas, it could be the exact same piece of equipment, price varies. So I just say, the CALiPER prices are point in time. Regarding any specific CALiPER data and efficacy in color temperature, I would refer—I would direct any comments to refer back to the specific CALiPER report.
Jeff McCullough: OK, thank you, Michael. Let's give a couple to Jason, and this is a pretty important topic. I'll give it to Jason, but, Michael, feel free to chime in as appropriate. Here's the question: How are LEDs sustainable for functional architectural light when the light level decreases below that needed after only five years? So basically talking about the lumen maintenance associated with solid-state lighting and how do you factor that into your designs. So go ahead, Jason.
Jason Tuenge: Yeah, and this is definitely a tricky one. Basically you have to look at it big picture, make sure that the lifetimes are being compared apples-to-apples. Unfortunately the way fluorescent lamps are rated is different from the way LED is rated. LED does not just simply fail. It just doesn't stop putting out light, at least not typically. Instead it just diminishes an output over time and it can take awhile to diminish an output and it can happen very quickly. It depends again on the quality of the product. Compare with fluorescent and you get ratings of something of comparable nature, but then you're going to have a certain number of those—of your lamps fail before they reach that rated life. Some will then also build beyond that rated life. So it does make comparison difficult, but the L70 point was selected as being something that is generally considered acceptable in terms of diminished output over time. The key is just to make sure that you're designing your system accordingly so you just don't design for initial output. You design for maintained output and then do your full analysis. Do your proper due diligence and demonstrate that over time these things will save energy. DOE is definitely not simply stating that by going to LED, you're being sustainable. We're actually doing quite the opposite. We're trying to explain to people: You really need to do your math and there are certain applications where now LED makes sense, but there are a number of applications where it simply does not.
Jeff McCullough: Thank you, Jason. Let me follow that question up, Jason, with a similar one and what the questioner is asking is: What is your basis for determining LLD factors for fluorescents and LEDs? So I think you answered part of it, but maybe you can specifically answer the LLD factors and how those are applied.
Jason Tuenge: Well I think, yes, I've already touched on this a bit. I think what this is getting at is driving home the point of making sure you're comparing these things apples-to-apples when you're doing your analysis. So it's really been the habit of industry to simply look at mean lumen ratings for other technologies, i.e., other than LED. And this may or may not be appropriate for your application. Again, I've been at this for ten years and this has been a pet peeve for me just to see that this is consistently done. And especially when you look at outdoor applications, it's really not appropriate to look at mean lumens. The way things are maintained is typically not group re-lamping, but just simply spot replacement of things as they burn out. And so you want to make sure that your looking in many cases at end-of-life performance, not the mean lumen output over the things life, and you need to make sure that you do—apply the same evaluation to both LED and whatever technology you're looking at. So if you're going to look at mean lumens, also look at mean lumens for LED and therefore look at something in the neighborhood of 0.85, not 0.7. But again, in many cases, you probably want to be looking at end-of-life. So just make sure you're being consistent in your treatment, whatever technology.
Jeff McCullough: OK, thank you. One more for Jason. This is somewhat of an open-ended question, but I think you'll do fine in filling in the blank so-to-speak. It sounds like LED is not a good replacement, and in parentheses, (at least at this time for linear fluorescent). What applications do you suggest as being a good application for LEDs or solid-state lighting?
Jason Tuenge: Oh, yeah, that's a good question. That one's been around since DOE has really gotten involved in LED, and that's—that question really drove the creation of Energy Star categories that exist. Basically the things to watch for, generally speaking, are—the first thing to look at is if a fixture type that has low optical efficiency. So we're all familiar with efficiency and we're getting more familiar now with efficacy now that we're looking at LEDs. So basically if you look at efficiency for existing products and it's low, then that's probably going to be a good candidate for LED. So examples would include downlights, like recessed downlights, the round ones (although, square has become more popular recently), those can have pretty low efficiencies. Even though the lamp efficacy is quite high, you're trapping a lot of light inside. So that's one application that can make sense. More dramatic examples can be found in like exterior bollards that are louvered. If you look at the efficiency on some of those products, even though again you have good lamp efficacy or lamp ballast efficacy, the efficiency on those things can be awful, like down around 10% or lower, so that's a great—that basically has great potential for LED replacement, and so the same thing applies to step lights that are louvered. So that's kind of one of the guiding principles is to look for fixtures that just aren't very efficient and that requires some control of their distribution. So if you're focusing the beam at all, that usually drops your efficiency, so that's another good application for LED because they're already directional and not difficult to focus. So hopefully that helps.
Jeff McCullough: Thank you, Jason. Let's give Michael a chance to answer. We have about two minutes left for today's presentation, so we've got time for maybe one to two more questions. I apologize that, again, we have a great number of questions to go through and so we're trying to pick the ones that are asked multiple times and are most appropriate to the discussion. So a couple of questions for Michael and then we'll give it back to Terry to wrap things up. Michael, this is a question where the respondent or the questioner is asking: What are the dimming capabilities of solid-state lighting, and maybe you can relate that to what are the dimming properties of solid-state lighting relative to fluorescent?
Michael Myer: OK. Dimming any light source is always an interesting experience. Dimming is still being developed—making dimmer capability is definitely the number one issue right now when you're trying to dim LEDs. There are different methodologies of how the driver works and what type of dimmer is compatible with it. NEMA just released a white paper, LSD 49. LSD is their abbreviation for Lighting Documents, and it's—theirs is about dimming replacement lamps for incandescent. It's got kind of an awkward title because it uses replacement and incandescent in the title, but it's about—essentially that's focusing on capabilities of dimming replacement lamps. There's another dimming standard document actually DOE is supporting for ANSI and other bodies to write an actual dimming document, and that's coming out right now. And I can tell you that in the meantime, other programs are using such as Energy Star. Energy Star asks that manufacturers say upfront how the dimmer manufacturer is, who the—what product actually is compatible and not just listing and then an updated—rather than—and an updated URL rather than just saying, "Works with Brand X." You actually have to be specific with who it is. In the end, I would say, like everything right now, and actually this isn't just with LEDs, if I was dimming conventional technologies, get one, test it with the actual product you're trying to do, look for flicker and other factors because some products can dim, but then they have a flicker side effect or other side effect that you want to see. In terms of dimming fluorescent, fluorescent dims pretty well. Typically when you get down to the low light output, the energy savings are not the same. It is not as a one-to-one relationship. So for instance, some dimming ballasts, when they're dimming to 10% light output are actually drawing 25% power still, and that's just the nature of how fluorescent technology works so—but—so you're not always saving energy when you're dimming fluorescent at the low end. But at the high end, you can be dimming if you're [inaudible] dimming to about 40% or 60%, for instance. Again, dimmer technology and ballast need to all be paired with the right technology of whether it's two wire, zero to ten, dolly. Again, really the problems that we have with dimming conventional technology are similar problems we have with dimming LEDs, you really need to make sure the power supply and the dimmer can work together and make sure that you don't have any awkward light source problem such as color change or flicker.
Jeff McCullough: Thank you, Michael; and also, thank you, Jason, for your participation today. At this point, I will end the question-and-answer section and turn it back over to Terry to close out the day please.
Terry Shoemaker: Thank you to Michael, Jason, and Jeff, and thank you to all of you for participating in today's webcast brought to you by the U.S. Department of Energy. You may all now disconnect. Have a great day.