LEDs have failed to take over the way CFLs have because of the narrow light spectrum they emit. It's too monotone, and fails to replicate the "natural" light spectrum we've become so accustomed to in incandescent lighting.
Any attempts to solve the problem have resulted in a trade-off in efficiency.
Good news! Appears they have figured out a solution and now they can have their efficiency cake and eat a broad-spectrum glow too. (yes, i am groaning at my own ridiculous use of metaphor...) The solution involves some soft of nano-crystalline coating that retains the efficiency.
The upfront cost of LEDs continues to be the real problem. Their lengthy lifespan makes lifecycle cost pleasingly low, but upfront costs of 5-6x CFLs and incandescents irk potential buyers. Still, ironing out some of these other difficulties should help us make headway towards adoption.
Then there's the lifespan myth. CFLs only really work longer than incandescents if they are kept on continuously. Unfortunately, flipping them off and on frequently reduces their lifespan to about the range of the incandescents.
And then there's what to do if a bulb breaks. Myself, I'm not as worried about the mercury issue as some people seem to be, having grown up with mercury thermometers around and playing with mercury in school. So long as you don't ingest it, you should be okay. But I can certainly see why people who have small children or dogs would be worried.
Regardless, I look forward to when we can all buy LEDs and get it over with... Just don't remind me that some of the minerals used in LED construction are running out...
dining room fixture. They claimed they were equivalent to 40w bulbs. They were more like 20w equivalents.
Five of them didn't light the table enough to read by. I had bought them at Sam's club for about $6 apiece
and saved the receipt. They were all burned out in two months!!! I returned them and got my money back.
It was an interesting experiment. Lies, overstatements, and bloated promises at a high price tag.
My advice? Save your receipts.
The biggest concern is the blue-gray light. I figure with the right color tinted film, I would be able to live with that. (experiment pending)
The CFLs, again, the blue-gay light, the delay getting started, the noise, the mercury issue.
MJ Solaro wrote:The upfront cost of LEDs continues to be the real problem.
Unfortunately this is totally false. I have bought a LOT of LEDs for domestic lighting and they have a very high failure rate. It isn't the "LED" that usually fails but rather the inverters, switches and other elements the prove to be the weak link. But the result is the same, the product fails. This means that the claimed 100,000 hour lives of LEDs are false because the product as a whole is not delivering that life-span. This would be like claiming that a light bulb will last 100 years because the metal base will last that long. Problem is, when the filament burns out it's dead.
I'm not sure where you got the idea that LEDs have filaments
No, I did not say LEDs had filaments. The incandescent bulbs have filaments. When I said "Light Bulbs" in that last bit I was referring to conventional filament based light bulbs - thus the reference to a filament.
Saying an LED lasts for 100,000 hours, which is what is advertised, is like saying an incandescent bulb lasts for 100,000 hours. Neither do. In the incandescent bulb the filaments burns out. In my extensive experience with commercial LED light fixtures it is the switch, solder joints, voltage controllers, etc that are burning out. In both cases the weakest link in the chain is the limiting factor. On average the LED fixtures I've bought have lasted less than one year of normal household use. That is far less than the promised 100,000 hours.
I've been using the commercial domestic LED light fixtures now for over four years. I had great hopes for them but they're very disappointing. The good news is the ones I built myself work much better because I use better quality components. It isn't the LEDs that fail but if anything in the LED fixture fails then the system fails and that means it is useless. You can't claim 50,000 hours if your system doesn't run that long.
Walk wrote:but just to be clear, LEDs are semiconductors.
I know. I'm an engineer and have been working with LEDs, LCD and all sorts of other fun things since the 1970's.
Walk wrote:Failure time is now over 50,000 hours
That's what they claim but my real world results with dozens of LED lamps is that the failure time is measured in dozens of hours of useage. Most failed in the first month. Sure the manufacturer replaced them but it was a PAIN.
Walk wrote:They now have warranties of up to 2 years (find that in any other electronics?).
I have lots of electronic devices with two, three and even five year warranties. In fact, I even have some with lifetime warranties. Warrantee length is a strong indicator of manufacturer confidence, provided they're going to be around in that amount of time. e.g., a 10 year warrantee from an unknown maker is worth little but a 3 year warrantee from Apple is worth a lot.
If the LED companies are going to claim 50,000 or 100,000 hours then they should warrantee it for that amount of time. Running full time that would be 5.7 to 11.4 years of warrantee. Since the bulb's aren't being run full time.
In addition to the unreliability there is the problem of poor color quality. LEDs are making advances but they're not ready for prime time yet.
Working as a videographer for many years I never came across any equipment with over a 2-year warranty that I didn't have to pay an extra bundle for. Meanwhile, some of the LED bulbs I bought 2 years ago are doing just fine, still in daily use, and the video equipment is all obsolete (like incandescents and CFLs, I guess). Some of the bulbs I tried buying online came from firms who obviously converse better in Mandarin. Their bulbs were fairly cheap but non-functional immediately or shortly after purchase, they cheerfully and quickly replaced them, and then even the replacements were faulty!
The rule of thumb with electronics that I used to hear all the time was something like, "If it runs right for 100 hours it'll last forever". Sounds like "pubwvj" are I are about the same vintage in terms of how long we've worked with circuits. I don't know where anybody managed to find a 100,000-hour lifetime for led lights. Digi-Key, among several other companies, offering the Cree, Edison, or Phillips Luxeon "light-engine" diodes as components for bulb manufacturers, use the more conservative 50,000 hours with a slight fading of output near the end of their life. The power supply issues really only apply to the 85-265-volt voltage conversion and stabilization circuitry in AC bulbs, not the simple wiring of the 12-volt or 24-volt DC models. I prefer to use low-voltage lighting just because I don't need to run an inverter all the time in our PV-powered home. Fewer voltage conversions makes for more efficiency, less EMF, and fewer worries about eventual inverter failure (14 years on our Exeltech so far, but only a year's warranty; hmmmm......).
A 2pack of nightlight size... one didn't work out of the package, the other (cheap walmart 5 white LED) seems to be fine and keeps our dark hallway safe. Only 4 or 5 months old, so it will be a while to see. The one that didn't work, is a cold solder... hold it right and it works... I will scavenge parts.
2 or 3 plugin LED night lights. They have been working for 3 plus years, but because of their low output/power, they do not get hot and will probably last "forever".
1 "flame" shaped white LED bundle (cheap walmart) to replace yet another failed CFL. It is one of a group of three and lights the bathroom area as it's CFL "warm up". Only 4or 5 months so far, but gets turned on and off more than the night lights above. Time will tell.
2 high price warm new tech lights 8 watt. To use as reading lamps. Only about one month old so far. The light seems to my eyes like incandescent light. Are dimmable, don't get too hot... so far we really like them... again time will tell. I got them at home depot and while talking to the salesman/stockboy? I got the idea they have had a lot of LEDs returned. I also noticed that there where two bulbs with the same stock number. The old one was rated 9watt and these new ones were 8 watt. So I think the manufacturer's solution has been to use the same power supply/heat sink, but to decrease the power drawn by the lights (or use lower power LEDs) and also the heat output.
Some things stand out in my mind. The harsh white LEDs seem to last better... they might be the best choice for emergency lighting and outside use. They also seem to work good as one of a group of CFLs to give you some instant light at turn on time... The CFLs fill in the colour once they warm up.
Watch out with heat sink style warmer LED. Get the newer generation even though they are a bit dimmer, they "should" last longer. Don't get old, on sale, clear out stock.
Low voltage is better. Duh. Match the supply voltage to the lamp voltage as close as possible.
screw type sockets are NOT the best form factor for LED Lights and calling them "bulbs" is a mistake. To really make the best use of LED tech, lamps need to be redesigned to have a separate power supply/heat sink and wider spacing of the LED lamps themselves so that better heat sinking is possible.... this means there would be no going back to incandescent lamps unless a "socket" was included as part of the new design.... not going to happen. If the lamp is designed with LEDs from the start, the lamps probably don't need to be replaceable. The high cost of designing the the power supply and heat sinking right, gets swallowed up in the overall price of the light fixture. They should be able to last years without attention and ZIF sockets would work well for the LED elements. However, most people replace light fixtures that are that old... Things are changing, but a lot of people move about every 5 years... or if not they do tend to remodel and lamps is one of the easy ways to give a room a "new" look. The best thing would be to offer lights with or without replaceable parts.... but lower price will win out.
BTW CFLs do not work well to light "electric fire places" I went back to the old filament... There are not yet LED lamps that would throw the right pattern of light available.
Just my two cents worth...
2-3 years to scale up the new tech, after that $10 LED bulbs...
Why All Your Bulbs May Soon Be LEDs
by Fast Company Staff on 03.11.11
DESIGN & ARCHITECTURE (lighting)
From our friends at Fast Company, "bridging the fuzzy border between design and business."
A breakthrough in producing light emitting diodes could see LED production costs tumble as much as 75%. That's thanks to research by a startup called Bridgelux, which has resulted in a radical shift--Gallium-nitride LEDs can now be grown on silicon substrates for the first time in a "commercial grade."
The tech leverages the huge, ultra precise and far cheaper silicon wafers that
are used in silicon chip manufacture instead of the smaller, more
expensive sapphire ones. The breakthrough has been to successfully grow white LEDs on a silicon substrate to create devices that produce 135 lumens per watt of electrical power--well above what typical CFL bulbs can offer, and around 10 times better than old incandescent bulbs.
So how big a deal is this? Pretty darn big. After all, did you know that those tiny flickering LED lights that sprinkle the power buttons of pretty much every device you own often need sapphires as part of their production?
Sapphire is key to producing white LEDs. It's artificially grown, rather than being dug up from the rock, but it's pretty much the same as the precious gem material you're probably thinking of--meaning it's rather expensive. Slabs of crystalline sapphire about four inches in size act as a substrate during LED production: The complex layered recipe of semiconductor chemicals that actually make up the LED devices is "grown" in various process on the precise surface of the sapphire, and then cleaved from it at the end before being chopped up and packed into the more familiar dome-shaped LED unit.
But sapphire is part of the main problem facing wider adoption of LED lighting--it makes the cost of high-brightness white LED light bulbs prohibitive compared to compact fluorescent bulbs, and many times more expensive than incandescent bulbs: $40 is a pretty common price bracket for LED bulbs that put out the equivalent light of a 60-cent 60W incandescent unit. Yet many people desire the LED tech very much because the bulbs can have an incredibly long life span, measured in tens of thousands of hours, and they consume much less electricity than their older equivalents.
Now Bridgelux thinks that after the two to three years needed to ramp its new tech up to production scale, the cost of producing LEDs will drop by three-fourths. Ten times greater electrical efficiency, ten times the lifespan of old bulbs and a much more affordable cost? Yup--soon every light you encounter may be an LED one.
By Kit Eaton at Fast Company
If the new tech puts out 135 watts/lumen in reality instead of in the lab that would be a considerable improvement, but I already waited and researched for 3 years to find the ones I bought. Hard to say at this point if any newer tech would be immediately cheaper.
For those with CFLs that still work, I'd say keep on using them 'til they're dead, then see what's currently available. For those using incandescent I'd say buy LEDs from a reputable source now and save nine-tenths of your power outlay on lighting. For those using kerosene lamps like I used to, I'd say save your lungs for breathing, not filtering combustion by-products!
What seems really cool about this one, is its reuse/reclaimability.
Switch bulb designs are inspired by the Cradle to Cradle® principles and are designed to be 100% reusable or reclaimable. When a bulb is returned to Switch at the end of its use, none of its components will ever see the inside of a landfill.
Do the next thing next. That’s a pretty good rule. Read the tiny ad, that’s a pretty good rule, too.
It's like binging on 7 seasons of your favorite netflix permaculture showhttp://permaculture-design-course.com/