LED Lights, a Perspective

Okay, hopefully that will create some interest in what otherwise would be the mundane subject of a light bulb. But as Lee Corso says on ESPN, "Not so fast my friend." First, the basics: an LED light bulb is the implementation of Light Emitting Diodes to replace the traditional incandescent bulb that's been with us since the days of Thomas Edison. The incandescent, as we know, uses a  thin strand of tungsten wire that is delicately strung between two little supports and gets extremely hot when the light is turned on. It's in a vacuum, so it doesn't literally burn itself to a crisp immediately. Over the years, the design and implementation have evolved, but it still doesn't last very long, uses a lot of energy (a 75 Watt bulb uses 75 Watts of electricity), and gets really hot since the wire inside acts like a resistor that glows white hot. Most of the energy comes off as heat, but there is light as well. This design has lasted many years. It's inexpensive to manufacture, and has become ubiquitous the world over.

But its life is coming to an end. Here's why. The LED lights use semiconductor technololgy, but first must get the usual house voltage (110 Volts in most of North America and a few other places, and 220 Volts most other places on the planet) down to about 1 Volt, and convert that to DC voltage to operate. The design and implementation still is new and expensive compared to the tried-and-true incandescent bulb technology. But the advantages are so impressive and overwhelming, it's only a matter of time until the LEDs take over much of the market.

Here is a summary of some key data,  including the Compact Fluorescent Lightbulbs, which essently, are small fluorescent bulbs designed to fit into the form factor of a "screw in" bulb to mate with the traditional sockets. Remember that the CFLs include mercury, and must be disposed carefully. These data are for regular 60 Watt equivalent bulbs:

Incandescent     CFL       LED

Purchase Price                     $0.41           $4.00       15.00

Electricity Usage                   60W             13W         9W

Lumens (Light Intensity)        860               660          900

Lumens/Watt of Energy        14.3               51           100

Lifespan (Hours)                    2,000           8,000        25,000

Bulb cost over 10 years         $4.40          $10.95       $17.52  Assumes 6 hours/day

Energy cost over 10 years     $198             $43           $30

Total Cost over 10 years        $202             $54           $47

In our house, we just replaced all three 75 Watt spotlights in the kitchen with three "75 Watt Equivalent" LED spots, which are are  specified to use 14 Watts of energy for the same brightness, and last for 25,000 hours. The LED "spots" cost $28 each at Home Depot, and replaced $8.00 spotlights, so they now are down to four times the cost. The light in the kitchen is fantastic, much more balanced and full, and ... this is the best of all, the kitchen no longer gets hot when my wife and I work under the spotlights preparing food. It's cool, and brighter, and much, much more pleasant. In fact, I tried one of the new lights when one of the incandescent floodlights burned out, to see how we liked it. The difference in the quality of the light coupled with the coolness sold us, and I went back the next day and bought two more to convert all three to LEDs. We'll never go back.

Now let me comment on one additional thing. It's fascinating and underlies nearly all of the new developments including digital phones that replaced analog phones, smart phones (read iPhone) that replaced digital phones, high density TVs that replaced analog TVs, semiconductors that replaced vacuum tubes, and radial tires that replaced bias-ply tires. In all these cases, the "new thing" was more expensive at first, but eventually offered better features and more value, and now its predecessors are obsolete and found only in isolated pockets and in the history books.

The phenomenon is called the Experience Curve and is well understood. It was first documented by the Boston Consulting Group in their book "Perspectives on Experience," published in 1968. The over-riding rule is that a new technology's costs will decline by 20% to 30% every time the cumulative volume doubles. The cumulative volume is the overall total number of units produced by all the suppliers. So when those first very expensive high density digital televisions came out several years ago, they represented such a step forward in the viewing experience, plus offered other options, that leading-edge adopters paid the high prices, and then the word got around about the super new thing, and now the price was lower, and yet more people went for it, and so on and so on until the costs versus the features and benefits were unbeatable. it was only a matter of time until the previous technology was dead. This will happen to the incandescent light bulbs. This conversion will be aided by governments and utility companies that want to conserve electricity and not have to build additional power plants.

I happened to stumble on a Sean Hannity program a year or so ago, and he was mocking the new technology, since it was so expensive and "who in their right mind would want this stupid new thing," and "how dare the government edict what I buy." It was mocking and condescending, and above all illustrated that he had no understanding of the market forces as well as technology development momentum. Ask him about it in several years when no one in their right mind will want the old incandescent bulbs.



2 Responses

  1. Hi Jim - There is one number all-too-ignored. Not even sure how it is standard-measured, but maybe switching mtbf ? Frankly, I have not been terribly thrilled by CFL on this and would LOVE to know how LED stands up to switching off and on. I am not big on leaving lights running when not needed, but switch mtbf sure seems to enter into the equation- especially when looking at the price on LED lighting. I know you cited Sen Coburn in a prev post, I wonder if he (& Hannity) will ever acknowledge the existence of something called 'science' ? 73, Howie N4AF
  2. Bill Haddon
    In comparing 10-year total cost of operating the 60 watt incandescent bulb vs. the LED Jim appears not to have used an inflation factor for the cost of electricity. If that's included at 5% per year then the 10-yr cost of operating the incandescent bulb increases from $198 to $252 while the op cost for the LED increases from $30 to just $38.

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