Saturday, February 23, 2013

Light Emitting Diodes
Published in the Sun February 23, 2013

Kelly and Pam Kimbrel displaying some of their LEDs at Texas Bright Ideas

Thomas Edison did not really invent the light bulb.  Scientists had been tinkering with incandescent electric light for 70 years before Edison devised a proper filament.  But Edison made the light bulb practical for regular people to use and, here’s the real genius that revolutionized the world, he figured out how to sell electricity so his customers could use their new light bulbs.


In 1882 the Pearl Street Station of the Edison Illuminating Company in lower Manhattan fired up for the first time.  Edison had 85 customers with a total of 400 light bulbs.  When the power plant turned on at dusk each evening, it might have cranked out enough to power the gadgets and air conditioner of one good-sized house.


Edison is reported to have said that “after the electric light goes into general use, none but the extravagant will burn tallow candles.”  At that time, of course, a person had to be extravagant to use the new-fangled light bulbs.  Edison was charging 24 cents per kilowatt-hour.  Adjusted for inflation over 130 years, that is about 50 times more expensive than electricity today.  Even so within two years the Pearl Street Station had over 500 customers lighting their homes with electricity and generating stations began springing up across the nation.


Other than a few updates to the filament, the incandescent light bulbs available today are virtually identical to the ones Thomas Edison sold 120 years ago.  Modernization has been slow in the lighting industry.  The biggest problem with incandescent bulbs is that they are not really very efficient at making light.  Ninety percent of the energy they consume is wasted in the form of heat.  In a Texas home why would anybody want to generate heat off the light bulbs?  That just requires more air conditioning to combat the heat, wasting even more electricity.


You may have heard that the federal government is trying to ban incandescent light bulbs.  Not exactly.  New efficiency standards for light bulbs require more light to be produced per watt of energy consumed, and some of the old-timey bulbs are not able to meet those requirements.  A few people are upset about losing the inefficient bulbs because they prefer the “warm” quality of incandescent light.  I imagine that in Edison’s time there were people who preferred to stick with romantic candlelight.  Can’t you just hear them: “Turn that danged contraption off, Mabel.  It’s nighttime; it’s supposed to be dark!”


I went over to Texas Bright Ideas, a lighting store in Wolf Ranch, to ask owner Kelly Kimbrel about LED lights.  LED stands for light-emitting diode, and they generate light by the movement of electrons in a semi-conductor.  An LED has more in common with your computer than it does with Edison’s bulbs.  Not only can a 10.5 watt LED produce as much light as a 60 watt incandescent bulb, but it will last about 25 times longer, so it is a great choice in a location where it is difficult to change a bulb, like a high ceiling or a streetlight.  When an LED finally does wear out, disposal is not a problem because, unlike compact fluorescent bulbs, LEDs do not contain mercury.  Also in contrast with compact fluorescents, LEDs come on instantly with full brightness, and can be turned off and on frequently without shortening the lifespan of the bulb.


At present, LED fixtures make up less than 5% of Mr. Kimbrel’s business, but he believes they are the wave of the future.  When he and his wife built their own home, they installed a wide variety of lights, including both compact fluorescent and LED fixtures to compare for themselves.  They have since replaced all the compact fluorescents with LEDs.


One feature of the Kimbrel’s new lights is especially appealing.  LEDs emit very little ultraviolet light so insects are not attracted.  The Kimbrel’s outdoor kitchen has an LED over the barbecue grill and a ceiling fan with an incandescent light over the sitting area.  The bugs swarm around the incandescent and ignore the LED completely.


After visiting with Mr. Kimbrel I headed over to Home Depot to see what kind of LEDs are available to a person who just wants to change a light bulb.  Since an LED is shaped like a computer chip, it can be put into almost any size or shape of device.  It doesn’t have to look like a light bulb, but many of them are made to look bulb-ish so we consumers will recognize them and put them into our lamps.  I found a 60 watt equivalent bulb-shaped LED for $15.  That sounds like a lot, but burning 3 hours a day it will last 18 years, compared to 11 months for an incandescent.  And while the incandescent uses over $7 of electricity a year, the LED gets by on $1.26.  Within two and a half years the LED will have paid for itself.  If it lasts the entire 18 years I will have saved over a hundred dollars in energy costs, which is a pretty bright investment.


  1. Haha, yes LEDs are better than incandescents in every measurable way, and that was already the case six years ago when I first discovered them. So why aren't they everywhere now?

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