An LED lighting revolution is underway. LED light bulbs are rapidly increasing in performance capability and decreasing in price. Last year, A19 format LED light bulbs, the common household format, sold in the range of $20 to $60. There was a strong correlation between price and quality. This year, top-of-the-line bulbs, such as the LG bulb, can be purchased for $10.
LED light bulbs have about the same efficacy as compact fluorescent light bulbs (CFLs), 50 to 60 lumens/watt. However, LEDs keep getting better while CFL technology has plateaued. The 7.5W LG bulb emits 485 lumens. This corresponds to 65 lm/W. It’s a 40W equivalent. At the same 485 lumens, the old fashioned 40 W light bulb would offer only 12 lm/W, five times less.
The LG 7.5W LED A19 Light Bulb LB08D830L0A.E50JWU0 in and out of its
packaging (click on image to enlarge).
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
David Patterson, known for his pioneering research that led to RAID, clusters and more, is part of a team at UC Berkeley that recently made its RISC-V processor architecture an open source hardware offering. We talk with Patterson and one of his colleagues behind the effort about the opportunities they see, what new kinds of designs they hope to enable and what it means for today’s commercial processor giants such as Intel, ARM and Imagination Technologies.