Illuminating 7/4/19

By Richard Bleil

Ugh, another new style of light bulb.

Light’s a funny thing. It seems like it should be so simple to illuminate a room. Well, we’ve come a long way from candles (which are seriously cool and very romantic but terribly inefficient), and light bulbs have become so common in our lives that they hardly seem difficult or noteworthy. But, maybe we should take a few minutes to shed some light on them.

Yes, I’m very punny.

An incandescent light bulb (the old-fashioned light bulbs with the filament) uses about 60 watts of power to produce 800 lumens (a measurement of brightness; my ex-wife, for example, had a negative lumen rating) of light. Thomas Edison did not invent the idea of the incandescent light bulb, but rather invented the first practical one. The idea is based on “blackbody radiation”, which is a fancy way of saying that metals tend to glow when heated to a high enough temperature. The concept of this light bulb is to use electricity to heat a tungsten filament (yes, just like the metal in the wedding band I flushed down the toilet after she threw me out) to a high enough temperature to give of sufficient white light. The problem is that at this temperature, the tungsten reacts with oxygen and burns. What Thomas Edison did was find a way to create a bulb with a high vacuum so there is not enough oxygen to burn the filament. Your typical incandescent bulb will last an average of 1000 hours and tend to cost about $1.25 for each bulb.

There have been many redesigns and variations of the incandescent bulbs to be sure. They created bulbs that can burn brighter, longer, better, but the next real advance in indoor illumination that I can think of is the CFL bulb. These bulbs are filled with inert gases, and pass electricity through the gas exciting the electrons in the gas which emits light when they return to the ground state. These are akin to the old-fashioned “neon” bulbs, but the great advance was to take these bulbs and make them compact so they could fit into the light sockets designed for incandescent light bulbs. These bulbs are about twice the cost of incandescent bulbs (about $2.40 per bulb), but even at this higher price are actually far less expensive than incandescent. The CFL light bulb (the one with the big base) uses about 14 watts of power for the same amount of light. This means that the CFL bulbs use only about a quarter of the power of the old-fashioned incandescent bulbs. Replacing your bulbs with these CFL won’t cut your electric bill to a quarter of what it was, but it will cost a quarter of what you were paying for each bulb replaced. More importantly, these bulbs last for about 9,900 hours, meaning that if you include bulb replacements you’ll spend about $12.38 in incandescent lights for $2.40 worth of CFL bulbs. Even at the higher price point, the CFL bulbs are only about 20% of the cost of an incandescent bulb.

Today, LED lights are all the rage. Safer than CFL bulbs, they cost about the same (LED bulbs are about $2.50/bulb). These solid-state devices are designed from materials that also have electrons jumping, but instead of in the gaseous state, they jump from a filled ground state to “holes” in the electronic structure of a different solid. I know, it’s hard to imagine, but the point is it too works with excited electrons relaxing back to the ground state and releasing light. It may be hard to justify choosing LED over CFL bulbs. The LED bulbs are about 5% more, and last for 10,000 hours which is only about one percent longer. The biggest savings is in power. Modern LED based lights use about 10 watts of power, which is about 30% less than CFL bulbs (and, as I’ve said, their safer). It’s kind of fun to note that the new LED bulbs use about 1/6th the electricity of the old incandescent bulbs. This means you save even more in electricity for about the same cost as CFL bulbs.

For a brief time, the previous president banned the old-fashioned incandescent bulbs until the current one reversed that decision. What I don’t understand is why it should be necessary to have a ban at all. Any drop in the electrical bill will probably won’t be noticed immediately, especially for people like me who replace light bulbs incrementally (that is, as they burn out), but eventually replacing all lights with LED will reduce the light component of your electrical bill by about 85%, which is pretty impressive. Add to that the money saved by longer lasting bulbs and the convenience of lights that will last for many years and the pocketbook is a strong argument for LED lights.

More than that is the ecological argument. We have destroyed our planet by reckless choices in power production, but even a switch to “green energy” is only half of the solution. If we are to survive, we also must become more frugal with how we spend our energy; that is energy conservation. The world population continues to increase, and any energy production technology will quickly become taxed beyond sustainability if we don’t couple the green energy production with conservation.

It’s one planet. We need to start acting like it.

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