“Shedding some light on Bulbgate” (Gail Collins, New York Times)
This recent article in my local newspaper reminded me that media people do not necessarily have the scientific background to understand an issue.
Ever since the announcement that Incandescent light bulbs will be banned in 2012 I have wondered how to get this issue into the right perspective. I am all for energy efficiency when the facts are clearly presented but in this case we have people that passed math but slept through science. What should it tell us when the world’s oldest Incandescent light bulb has been burning for 109 years? Context, please.
A statement that needs to be questioned, because of the lack of scientific context, is: “Fluorescent and LED lamps will save more energy when we use them to replace Incandescent lamps”. The scientific fact is that if you put 100 Watts into an Incandescent lamp, you get 100 Watts out, part of it light and part of it heat. This is called in Physics as “Conservation of Energy”. The same is true for CFL’s and LED’s, the only difference is the proportion of heat to light. So then the question should be if we get heat as part of the output from a device that is intended to produce light, is that a bad thing. I say Yes and No. No, if the heat energy from the lamp offsets the energy being used to heat the surrounding air where the lamp is being used; Yes if the heat is undesirably adding to the surrounding environment. In the latter case, the question might be how often is the lamp turned on in a bright, hot environment compared to the dark and cool of the night? Does the heat from an Incandescent lamp impact the surrounding area noticeably more than the Fluorescent or the LED? My experience is that I have never been able to tell the difference.
What should be a bigger part of the conversation is this:”which technology is more reliable and which is less expensive?” I say, when not abused, the Incandescent lamp wins hands down. Statements from Proponents for eliminating the Incandescent bulb make out of context claims like “LED’s will last 25,000 hours (less than 3 years) instead of 1,500 hours (2 months) for the Incandescent bulb”. The absurdity of the statement is shocking. A LED chip alone may quite well last 25,000 hours but since an LED lamp includes numerous additional components, including multiple LED chips, collectively it will have a much lower life expectancy, and is very expensive. The Incandescent consists of ONE component and if treated right will survive well beyond the 25,000 hours. Let’s talk about the mistreatment of the device, what is the cause and how to avoid it.
The Incandescent lamp is an inexpensive and environmentally friendly device because it consists of a thin metal wire with a positive temperature coefficient (so it won’t run away and self destruct). Its’ Achilles heel is the fact that due to the positive temperature coefficient, it has a lower resistance when cold and if the rated voltage is abruptly applied the initial current is much larger than when the metal wire (filament) finally reaches operating temperature. This inrush of current causes a sudden heating of the filament which causes a wrenching change of dimension. In addition, since the filament is extruded and will have slight variances in cross section, it will have points along the filament that will be higher resistance and will become exceptionally hot. In time it will degrade and fail. The solution to this is to NOT apply the voltage abruptly; don’t flip the switch. Low cost dimmer controls (e.g. Lutron Corp) not only allow you to adjust the light output to the level you need and/or want (saving energy), it also applies and removes the voltage slowly, giving the filament time to heat (expand) and cool (shrink). Therefore all of my Incandescent devices are operated by a dimmer control. The time to turn a knob or slide the control versus flipping a switch is negligible, it becomes such a habit that I don’t even think about it. One caveat is that the control must NOT be a push on-push off variety because that will still makes an abrupt application of the voltage. Incidentally I have never had to replace a dimmer control because of the simplicity of the design whereas dimmable CFL’s and LED’s require you to throw out the dimmer part of the device when it fails because it is integral to the device. One last note here, since a 100Watt incandescent can be dimmed and will consume less energy, why is that not a good thing? Only dimmable CFL and LED lamps can do that but with a much higher cost and, due to the complexity of the controls, have lower reliability collectively. Why would you pay more for something that will fail more often?
Lastly, the way to save energy while getting the illumination that you want is to use it wisely. I sometimes get the impression that the drive to go to more efficient, expensive lighting sources is so that we can have more of them burning brightly in our house and not feel guilty. When young I did not really understand when my father berated me for not turning off the light when I left a room, but over the years I now do.
Last thought: How come they are not outlawing Candles? Geez, I hope not.