Before we rush to get rid of incandescent bulbs, we should honestly acknowledge their virtues, as well as the shortcomings of electronic alternatives
There's no doubt that that the venerable incandescent light bulb is on the way out. Legislation and energy concerns are discouraging or eliminating its use.
Certainly, the energy efficiency (lumens output per watts input) of such bulbs is far lower than "electronic" alternatives such as standard fluorescent bulbs, compact fluorescent lights (CFLs), and the up-and-coming LED-based area illumination.
Yet, there's both an esthetic backlash and maybe a practical one to consider. A recent article in The New York Times talked about a trend in eateries and other chi-chi places towards exposed-filament bulbs, "Vintage Light Bulbs Are Hot, but Ignite a Debate". Like most such trend-focused articles, this one was short on data and facts (let's call it "anecdata"), and long on speculation–and even hedged its bets by saying that maybe the trend has already peaked.
I'll put the esthetic arguments aside, since that is largely a matter of personal taste and hard to quantify. But the argument against incandescents has some technical weaknesses:
- In many situations, the so-called waste heat of the incandescent is not actually wasted, but serves to help keep a cool area warm. It's a form of electrically sourced heat.
- What about the use of incandescent bulbs in extremely hot or cool consumer applications, such as freezers, ovens, and dryers? You can get a temperature-ruggedized incandescent bulb for just a little more than a standard bulb, but I don't see electronic blubs (neither fluorescents nor LED) being viable for those situations coming soon.
- The disposal and recycling of incandescents is pretty straightforward; that's not so for electronic bulbs.
- Electronic bulbs are non-resistive loads, and thus have power factor correction (PFC) issues that must be addressed. And they are difficult to dim, compared to the standard TRIAC-based dimmer used for incandescents.
- Finally, electronic bulbs–especially fluorescents–require a lot of resources to manufacture, and have a long and complex bill of materials (BOM): ICs, passive components, PCB, packaging, and more. It's easy but misleading to ignore that reality or pretend it is not a factor to consider in total environmental cost.
I am not saying that the electronic bulbs are a bad idea, only that they are not a solution in every application, When we decree that a new technology is the only way to go, we are saying one priority is so overwhelmingly important that we can ignore the other factors that go into making a design and selection decision. And that's a bad road to go down, whether in a PCB design or a consumer-product situation. After all, sometimes that road to you-know-what is paved with good intentions, and unintended consequences.♦