Presented at MD Green Buildings Conference 2009 March 25, 2009
To LED or not to LED? Is that the question?
By Bob Gilbert
Efficient Lighting Specialist
Should we use LEDs? That seems to be the current, most commonly asked question.
Whether it is nobler and wiser to be on the ragged edge, or to be content with merely the cutting edge, that is our dilemma today.
How do we implement the best lighting project possible while taking into consideration maximum energy savings, client comfort and well being (and hence productivity) while finding the most cost effective solution?
Max Light / (Max Energy Savings + Comfort & Productivity) to = Maximum Cost Benefit
The answer is…
It’s Application Specific. One Technology fix does not fit all.
Hello. My name is Bob Gilbert, and I have been working with Hunt Consulting & JCI and other preferred partners since 1986 on approximately $100 million in installed energy efficient lighting projects.
These include in this area, Prince Georges and Baltimore County Schools, Architect of the Capitol, Andrew’s Air Force Base, NIH, the State Dept, Dept of Agriculture and the White House (during a previous Democratic administration), retail chains, casinos, warehouses and just about anything else you can think of.
After all, lighting is everywhere.
I like to say we are the Marines of Energy Efficiency. Getting it done in the trenches every day for over twenty years.
Enough power saved to run a city of 50,000 or more.
So, everyone wants LED’s. News about LED’s is everywhere.
LED’s seem to be the answer to global warming, a balanced budget, world peace, receding hairlines, and just about everything else under the sun.
Lets look at what’s great about LED’s:
1) They are very cool. Actually they operate very well in cool environments too, though they can also be very sensitive to heat.
2) They are very bright, leaning towards blue on the Kelvin scale (5000 K and above) and though they do not quite yet meet fluorescent’s efficiency or color stability they are getting closer all the time.
3) They are very tiny. Can be made to fit in all sorts of great places you just can‘t stick a light bulb.
4) They use no mercury. Though the semiconductor (LED’s are a semiconductor) manufacturing process is notoriously littered with toxins and is volatile and dangerous. The dangers are limited to their manufacturing and to the disposal of the LED boards. Yes, what are you going to do with that circuit board when it burns out?
5) They can last from 50,000 hours (White) to 100,000 hours (Red).
6) They are a UV free light source, which can be very important in museum displays for fragile or precious artifacts, as well as illumination of foods like fresh meats and fish in grocery stores, which degrade quickly under fluorescent lighting.
7) Where as LED’s started out in exit signs, graduated to stop lights, brake lights, and displays; they are now everywhere from neon replacement to high hat cans to MR 16’s and track lights to street and parking lot lights.
“Great sounds pretty good to me? So what’s the problem?”
They are notoriously difficult in other traditional lighting sources for general illumination like light bulbs. I have a good LED light bulb. It’s $30.
You see…LED’s are a DIRECTIONAL LIGHT SOURCE.
The light shoots out from the chip and is difficult to disperse. It is difficult in the manufacturing (or binning process) to get consistent color. Problems with color shift persist as different blended colors depreciate at different lengths of time. They are very sensitive to heat degradation and line voltage surges. This absolutely must be carefully designed for or they will degrade or fail extremely quickly. Buyers beware and know what to ask.
They cannot be thought of as something you just stick into a traditional lighting package. That was tried for several years and the results were hokey at best, ludicrous at worst.
So where do LED’s work well?
Because they are UV FREE they do not degrade items that are UV sensitive like cloth, paintings, fragile paper, ancient artifacts, other perishable items like meats, fish etc.
Directional applications (brake lights, exit lights, display lighting, etc.)
Very cold environments like freezers in grocery stores.
Small localized sources of light such as cell phone or display panel.
We are seeing excellent applications for high hat cans and track lights.
We are also seeing them requested for parking lot and street lighting.
. A recent project in my home town of Raleigh NC, The city in partnership with Cree LED, installed hundreds of LED Parking lot lights at the new convention center. They are quite lovely; very modern. The fixtures are rated for 50,000 hours and cost $500. They will last 6 years. They saved 40% over the original Metal Halide fixture spec
But, there are two problems with these exterior applications – Cost and replace-ability.
They are very expensive. A 90-watt LED street light Cobra head can run well over $1,000.
Compare that to Induction Lighting that has been around for over 15 years (and is actually well represented here in Maryland) and is one half to one third the cost of LED, impervious to heat or cold and lasts twice as long (100,000 hours instead of 50,000).
And the lamps and ballasts are both replaceable in induction.
Until very recently, almost all LED fixtures were disposable. Once they reached their rated life, the circuit boards were not replaceable at the end of useful life so you have to throw them away - not very ecological. Since most current LED Street and parking lot lights do not contain removable, replaceable boards you are essentially buying a throw away fixture. Hmmm….
This is an unnecessarily high fixture cost and though they are ecologically benign in the life cycle energy usage arena, as circuit boards, they are toxic and difficult to recycle. The Pentagon is buying a whole series of lay in LED fixtures. Again, if the light source and boards are integrated and not replaceable, why buy a disposable fixture and call it Green when you can get almost the same life from a $2 extended life T8 lamp?
Now let’s look at some other options:
I recently completed a series of open parking garages in NJ near the ocean - a very tough environment. We replaced thousands of 175-watt MH fixtures with two lamp and three lamp T8 vapor tight four-foot fixtures for under $100 each.
Actually, we started out with three lamp 105-watt fixtures and the client said it was too bright and we went to a two lamp T8 fixture at 70 watts and still increased the light 40% as well as cut consumption over 60%.
In some areas around the periphery we installed daylight ballasts for further savings.
This specially designed fluorescent vapor tight with an application specific interior asymmetric reflector saved more than the LED’s by 20%, and the fluorescent lamps last 42,000 hours and cost $4 to replace.
These fixtures were ONE FIFTH the cost of LED. LED fixture lasts 50,000 hours. Ours, replace the lamps at 42,000.
A closer alternative to LED is Induction lighting. INDUCTION is an excellent option for parking lot and street lighting. I recently completed a project for JFK Airport Terminal One and the exterior lights and parking garages.
We are also involved in an ongoing replacement of all the 30,000 HPS streetlights in the Town of Islip NY.
Those fixtures cost under $300, use half the energy, improve light (and safety) by 30% and will last 100,000 hours.
Induction parking lot or street lights will last 100,000 hours and can use the same design like the metal halide fixtures I saw at RDU and BWI airports on my way here today. Yes, I flew and offset too.
They use half the energy of metal halide and cost again under $300 per fixture.
The down side, if any, to Induction is they do use a very small amount of mercury in their amalgam technology, about the amount found in a can of tuna fish. But since the lamps are only changed once every 100,000 hours they use less overall than fluorescent because there are no lamp changes. NO Maintenance.
And then there’s Cold Cathode - the next generation after compact fluorescent. It’s dimmable, flashable, waterproof, very small, and lasts 25,000 hours. Induction lasts 100,000 hours.
So the answer, as in most well thought out designs or retrofit applications…
* consider the current environment
* consider the needs of the client
And the answer is APPLICATION SPECIFIC.
SOMETIMES A $100 FLOURESCENT FIXTURE IS A BETTER FIT THAN A $500 LED FIXTURE. And sometimes a client wants to spend more for the exotic technology, politics or other factors. “Look, I don’t care we WANT LED!” Go figure.
And sometimes LED is the best answer too.
As always, we try to give the best solutions to save energy, improve the lighting environment, and be educate on true life cycle costs.
In the end, you the client must decide. After all it’s your facility.
for Hunt Consulting, Laurel, MD