When placed in a conventional table lamp most LED light bulbs, including this LG bulb, have a tendency to illuminate upwards. This is because of the horizontal placement of the LED emitters inside. The Philips bulbs use three vertically oriented LED panels to alleviate this concern. However, in an over the shoulder reading lamp or a task lamp, the bulb illuminates uniformly and does not throw any heat on the illuminated target.
The LG light bulb illuminates mostly upwards because of the horizontal
placement of the LED panel inside the bulb (click on image to enlarge).
The design of table lamps is meant to accommodate the Edison light bulb, which emits light in all directions. The spindle allows the electrical cord to reach the bulb and the lamp shade serves as a diffuser. The shade, being open top and bottom, allows the natural convection to take away the unwanted heat. It also enables easy replacement of the short-lived bulb. The electric table lamp has evolved over more than a century to accommodate the light bulb and is very different from its precursor luminaire, the oil lamp.
The very first electric lamps were not necessarily very effective or very popular, yet their advantages prevailed and the use of oil lamps waned. Over time, and probably rather rapidly, lamps will evolve to adapt to the peculiarities of the LED sources. When LED light sources achieve lifetimes in decades, replacing them will no longer be a concern and luminaires will take on various forms and shapes. Meanwhile, forcing LEDs to assume the Edison format is akin to forcing a square peg into a round hole.
Nevertheless, Strategies Unlimited predicts that "the global market for replacements for legacy lighting sources will grow from $2.2 billion in 2011 to $3.7 billion in 2016." Indeed, LED light bulbs provide very pleasant illumination, much more agreeable than compact fluorescent bulbs, and they will be adopted eagerly. They outlast CFLs, contain no mercury, and are instant-on. One annoying trait of CFLs is that they take a relatively long time to reach their maximum level of illumination.
LED light bulbs are complex electronic devices. The LEDs themselves are semiconductor diodes, wanting a low voltage DC supply, typically around 3 volts. Common household supply is 110V or 220V AC depending on geographic location. The LG bulb is not dimmable. More expensive models are dimmable, although newer types of dimmers may be needed. Like CFL bulbs, LED bulbs have a small circuit board stuffed inside the neck.
Dude, a good heat pump is 300% efficient (it doesn't create heat, it just moves it around, and thus). Even if your lightbulb is 100% efficient (heat + light), which it isn't, you're way behind the competition.
LEDs are far too expensive considering all the things that could go wrong over an expected multi-year life. How often do incandescents break due to accidents, problems with fixture etc???
Expect a very conservative ramp in these products - i.e., only new construction where builder puts them in and subsequent home owner pays the price without much consultation.
The savings of LEDs are very real. I recently bought several 4W GU10 100lumen/W SMD LEDs to replace 40W downlights. They cost just £6 per bulb including postage...
That means after just 833 hours they will have paid themselves back at £0.20 per kWh (yes, UK prices...). At 3 hours a day that's just over 9 months. So who cares if they last only a few years? They will have paid themselves back many times over by then.
@chanj: you are correct, the power electronics components will be the ones to die first, in particular the driver.
In the LED's, there may be an accelerated decay in the chromaticity / CCT of the white light depending on the ambient temperature and the hours of use. Without these mitigating factors, it is safe assume that LED's can last 10 to 15 years!
Incandescent bulbs have gotten a bad rap. OK, they're not especially efficient in making visible light. BUT there's is more to the problem set than producing lumens. In North America the vast majority of the population lives north of 30 degrees north latitude which means there is a significant seasonal change in hours of daylight. ALso, obviously there is a strong correlation between shorter days and lower temperatures - meaning that a residence requiring both heat and light simultaneously is to be expected. When I turned on the 100W incandescent on my nightstand this morning not only did I receive illumination but heat - as it was 9F outside any heat produced by the incandescent bulb was a welcome addition - and heat that my furnace then did not have to produce. While this little "space heater" may not be quite as efficient as my natural gas furnace in heating my house NOT A SINGLE JOULE WAS WASTED! Now the same can be said for the lesser amount of heat produced by any other electrically powered lamp - like LED. However, incandescent bulbs are cheap to make and are easily and safely recycled. OK so what happens on a warm July morning or evening? Well unless I'm getting up before 5am or VERY cloudy there will be ample natural light - and even at night, it's usually well past 8pm before I need to turn on interior lighting. Sure, the heat generated by my incandescent will indeed be wasted then, but only during this fairly limited span of the calendar. My back-of-the-envelope calculation shows that when you include the visible and infra-red light given off by an incandescent 100W bulb it's only at a ~15% disadvantage in total system efficiency compared to a similar amount of lumens produced by a MUCH more expensive LED bulb. BTW - I design LED lamps (commercial T-8s, etc) so I am no novice to solid state illumination.
About that Philips LED bulb, its quality issues, and issues over how
it won the US Govmt prize...
The poor quality of the bulb on testing and how competition rules were skirted - as referenced with competition rules, patents, lobbying
finance records, the prize committee's own lab test review document
and publicly less known designated lab test reports released on Freedom of Information requests.
All lighting has advantages.
No lighting technology can "replace" another.
LEDs are ideal in sheet or panel form,
Fluorescents in long tube form.
As with this warm fixed color temp incandescent copying Philips LED bulb,
they are compromised as politically pushed replacements for simple incandescent bulbs
- with particular difficulties to achieve omnidirectional and broad spectrum and, not least, bright 100W+ equivalent lighting in the small bulb format.
The Deception behind the Light Bulb Switchover
13 points, referenced
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