Goodbye to halogen bulbs, truths and lies of LEDs

Goodbye to halogen bulbs, truths and lies of LEDs

On September 1, 2018, it will go down in history because the ban on the sale of incandescent halogen bulbs began. In 2012, traditional ones were already banned in the European Union, and from that date halogen ones cannot be sold either. It has been almost 140 years of existence since the first patent in 1879, in the time of Thomas Edison. The current LED bulbs advertise much lower consumption and longer duration, but… how much truth is there in that? Traditional bulbs were very simple and LEDs hide surprises.

A radiant thread

When almost a century and a half ago, several types of light bulbs emerged, well Edison was not the only one, they all used the same principle. When an electric current passes through a filament, it heats up so much that it becomes incandescent and emits light. The bad thing is that it gets hot, a lot, and a good part of the electrical energy goes that way. It is estimated that 85 percent of what an incandescent light bulb consumes is evacuated as heat .

In its early years, the effort was focused on improving its life as the filaments melted. In the end, doing it in Wolfram gave the best results: at a reasonable cost, it lasted about 1,000 hours . There is a myth that a light bulb capable of lasting 200,000 hours was patented. Well, it is not a myth, it exists, but it was very expensive to manufacture and it was rejected for that reason ... perhaps one day there will be a place for something like that.

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The next major development of incandescent bulbs came with halogen bulbs. They work at a higher temperature and achieve better performance (more light and whiter). They also last much longer, between 2,000 to 4,000 hours normally. Instead of glass they are wrapped in quartz and contain a gas (halogen hence the name) that keeps the filament longer. When traditional incandescents were banned in 2012, halogens were “pardoned” thanks to their longer life and performance. Until September 2018, yes.

Low consumption

Both traditional and halogen bulbs require consuming enough electricity to illuminate well. The normal thing was to use bulbs of 40 to 60 watts, and sometimes up to 100 or more ... when not more than one bulb, of course. A normal house could be consuming about 500 watts any night with just the lights. When we are concerned about the planet, that is too much, too much, remember that more than 80 percent of that energy is heat . Except in winter and with a table lamp or nearby, that is lost.

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The first advance was the "energy saving" light bulbs. These were really miniaturized fluorescent tubes , as is evident when you look at them. The ballast needed to turn them on, and the tube itself, has been reduced so that they can be used instead of the traditional ones. The change was very remarkable: the light of a 60 W bulb, which a halogen gives about 50 W, was achieved with just 15 W. After its appearance there were not a few campaigns in favor of its use, even some sounded by the Government.

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But those bulbs already had some drawbacks. The first: they were much more expensive, five to ten times more than the traditional ones. It made up for that also supposedly lasted much longer, up to 8,000 hours or more. The second downside is that, as waste, they are much more polluting. They carry mercury inside as well as electronic components that degrade badly. And another downside, which is not on paper but which we know exists: its internal complexity gives rise to very different qualities. And the cheapest ones don't last nearly as long as the good ones . This still happens today, and surely it will have happened to you: some old bulbs continue to give light while the “new” ones fall one after another.


The next and final step in the evolution of light bulbs came with LEDs. Diodes that emit light by conducting current (LEDs) have been around for a long time. But until blue light was achieved (which earned its inventors the Nobel) they could not be applied to illuminate. Now we see them every day ... The performance jump is less great than with respect to fluorescent lamps, but notable. The light from that original 60 W bulb that could give us a low consumption 15 W bulb, the LED gives us 8 W.

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And the difference in duration is abysmal ... LEDs were quickly used in vehicles because they are practically eternal and very resistant to vibrations. Filament bulbs, obviously, end up melting with use and kilometers. An LED diode can last more than 100,000 hours (yes, one hundred thousand). The definitive solution? Yes and no.

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LEDs work with direct current and low voltage: they are ideal for use with batteries for example. LED flashlights have flooded the market, and it is a very good application of the technology. Now you can go hiking and have (lots of) light all night, something unthinkable a few years ago. That is why they also work very well in cars or motorcycles (low voltage and direct current or DC).

What they do not tell to you

But at home we have alternating current (50 Hz) and a lot of voltage (230 V). This is because it is much cheaper (even possible) to transport and distribute them. For an LED bulb to work plugged in at home, it needs to have a power source, an adapter. It is what reduces the voltage to the necessary level and also modifies or rectifies the frequency, so that the light does not flicker. And there is a key. A power supply consists of various electronic components, which can be better or worse, and their design can also be more or less elaborate .

I don't have to tell you that very low-priced LED bulbs don't use the same as well-known brands . Even in many cases, they already "warn": within the same brand there are usually low-priced bulbs advertised for 10,000 hours, and other more expensive ones in which it puts 20,000 hours. A good understanding ... And the worst thing is that, when real tests of duration have been done, these figures are rarely reached. We had one of the first LED bulbs animated by technological advantage, and we no longer have any. Many will not have lasted even the 1,000 hours of a traditional light bulb ... deception? You will say.

They don't last that long, nor do they spend so little

But there is more: neither the advertised consumption is usually true or real. That internal power supply is not perfect - they give 80 to 85 percent performance. That means that an “8 W” LED, one of two, is either actually consuming about 10 watts, or it does not give us the light of those 8 W but one or two less. Where does the rest go? Well obviously, in heat: LED bulbs get quite hot as you will have noticed if you have one. In addition, depending on the design of the source, this reactive consumption with current meters can be recorded as higher when invoiced.

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And that is another possible saving point: the need for heatsinks, which are made of metal (aluminum) and it is not cheap. You already have another reason why cheap LEDs last less, because they carry less metal and dissipate less heat. Apart from what they have invested in "ingenuity" (design), that is a key factor, the cost when millions are made.

As you can see, traditional bulbs had their drawbacks, but also their advantages. They were very simple and could be manufactured at low cost, and if in addition to light you needed heat, great. They have been banned from us , so it is not a bad idea to buy some while they remain ... Because LEDs spend very little, but it is not “so” little. And they last a long time, but they don't last "that long."