LED light output

Light emitting diode (LED) lighting is the only other practical alternative to normal incandescent bulbs and fluorescent light (besides natural light of course). This matters because incandescent bulbs are in the process of being regulated out of existence, and some people hate the quality of fluorescent light (among several other concerns). LED lighting potentially has an even higher efficiency than fluorescent, but is unfortunately ridiculously expensive.

Here is a comparison between the light output of an LED bulb to the normal incandescent bulb it suppossedly replaces, with pictures:
https://sites.google.com/site/unusualchemistry/incandescent-vs-led-light-output
The test was dissappointing. Current LED bulbs do not compare well to normal light bulbs, and the manufacturer's claims are very misleading.




I personally do not have a problem with the light from LED bulbs, although some people still prefer incandescent light.
The the biggest problem is that LED bulbs are so expensive. A 100-Watt equivalent LED costs between 50 to 90 dollars.

Sure, there are 10 dollar LED bulbs being sold, but they are very dim, hardly useful except as a night light. With the LED technology, you are paying in direct proportion to the light output.


So are LED bulbs worth it?

It depends how long the LED bulb's life span actually is. I do not think it is far-fetched to expect that the life spans claimed by the manufacturer of these "cheaper" 50 dollar lights (as compared to the 80 dollar ones) will be exaggerated. If we assume a typical lifespan of 10,000 hours, this can be seen as the equivalent of only 8,500 hours of incandescent light, when we remember that the brightness of the LED "fades" over time. A typical incandescent light bulb, in comparison, will last 1,000 to 2,000 hours. For several reasons, it is problematic to make a direct comparison, but basically it seems that a single LED bulb's lifetime is the equivalent of 8 incandescent bulbs. That is still 6 to 10 times more expensive than using incandescent bulbs.

An LED bulb will save 150 dollars over its useful life span in reduced energy consumption compared to incandescent bulbs. So to answer the question, it is theoretically "worth it" to buy LED bulbs, but only by a small margin. With incandescent bulbs, most of the cost is the electricity, not the bulb itself. With an LED light, the bulb itself costs more than the electricity over its lifetime.

Now it is claimed that LED bulbs can "last up to 25,000 hours", the "life span" of an LED bulb has a different meaning than for normal light bulbs. Normal incandescent light bulbs suddenly fail, whereas LED bulbs slowly lose light output, becoming dimmer over time. The rated lifespan of an LED bulb is typically the point at which the bulb puts out 70 percent of the light output it put out when it was new. And these lifespans are for the higher quality, more expensive LED bulbs. The 50 dollar bulbs are unlikely to last quite as long. We have already seen this with CFL bulbs, the manufacturer's life span claims are often very inaccurate, or misleading. Most people are not likely to keep track of how long the bulb actually lasts.

But with the high cost of LED lights (even if their longer lifetimes compensate for this) it will become likely that LED bulbs will become a target of theft. Burglaries may begin to target houses to steal their light bulbs. Many public places will essentially not be able to use LED bulbs because of the high risk that they will be stolen, much as we are already seeing with theifs breaking into street lights to steal copper wire.

Also, most stores do not yet carry LED bulbs, or only carry the very low wattage versions. At least for the time being, many consumers will have to order LED bulbs through the mail, and the shipping costs will no doubt add expense. (and just what is the environmental impact of all the fuel it is going to take to mail all these LED bulbs?)

 

For the benefit of lurkers out there -- several months ago, I replaced the 6OW incandescent bulbs in the recessed-ceiling fixtures in our kitchen with Home Depot $10 LED specials (9W each), and they've worked out very well. The increased directionality of LED's vs incandescents is less of an issue in recessed ceiling fixtures (where the primary directionality is downward).

Went from 540W to 81W max consumption. And those "dim, hardly useful except as a night-light" 10 dollar LED bulbs light up our kitchen like daylight. At our current usage and electricity cost per KWH, they'll pay for themselves less than 2 years. So if they all burn out after 3 years, we are still ahead.

My suggestion for those who are considering LED's is to buy one or two of those Home Depot specials and give them a try. They may not work out well in all applications, but if they don't, then you are not out *too* much money. But for recessed-ceiling installations (where the primary directionality is downward), they will probably work out very well for you. They certainly did for us (and at a greater than 80-percent reduction in electricity consumption).

All I will say is, from my personal experience, LED bulbs work quite well in recessed-ceiling fixtures (which are notoriously energy-inefficient when populated with conventional incandescent bulbs).

 

as with all new technology the kinks need to worked out first ,...the first phones were cr*p, first cel phones were huge, expensive and cr*p, first computers were primitive compared to we find in today's smart phones...and so it will go with lighting technology, I've been in the construction industry my entire life and I'm astounded how fast new technology has developed, what's being done with lighting is amazing ...

I began switching to newer lighting technology years ago, the first were not so good but now that's all I buy they're great and LED's will go the same way and in a few years time the complainers will all disappear into their caves...

 

I agree. I tried the LED bulb in all the different lamps in my house, desperately trying to find a place for it. It either did not fit in any of the lamps, or did a terrible job at providing light because of the directionality. I finally ended putting it in the bathroom in a lamp that had the lights facing downwards. It would similarly work okay in recessed lighting. So while these type of LED lights may not be appropriate for most lighting applications, there are some limited places where they will work acceptably.

The main problem seems to be that most of the light fixtures were not designed for directional LED lights, and are not really compatible with them.
I really learned much by actually buying an LED bulb and testing it. There were many complications and problems I had not previously considered.

It also, for some reason, seems much more difficult to read using LED light than normal incandescent bulbs. I do not know if this is because of the color difference, or if there is subtle high-frequency flickering (which would not be consciously discernable) that causes eye strain or trouble concentrating. But I still prefer LED more than CFL bulbs.

That is likely because regular light bulbs give off their light in all directions, and so much of the light would be potentially wasted if it is inserted into a crevice in the ceilling. The reflectors might reflect some of the sideways light downwards, but the geometry of these type of reflectors are not the most efficient. For this use, it is best to have all the light focused downward to begin with.

Yes, my advice would be to just buy one or two LED bulbs and actually test it out in different places in your house first, because LED bulbs may NOT suitable for most lighting uses.

I am just concerned the new laws (that effectively ban normal incandescent bulbs) will cause everyone to have to switch to CFL, and that very few people will buy LED because of the much higher initial expense. If this happens, the LED technology is not likely to progress much.

 

Actually, the incandescent bulbs that I replaced were specifically designed for recessed fixtures -- directional, with built-in reflectors to focus the light downward. The LED bulbs that replaced them weren't designed for such use -- they are much less directional than the incandescents they replace, with a greater portion of their light "lost" in the fixtures. Even so, they still light up the kitchen (@81W) every bit as well as the incandescents (@540W) they replaced.

 

I put the LED bulb in the bathroom, and did more comparisons with different wattages of incandescent bulbs.
The 18 Watt LED bulb seems only about as good as lighting the bathroom as a 75 Watt incandescent bulb.

Again, 18 Watts is about the brightest type of LED bulb available. That claim that it is a "110 Watt equivalent" just does not seem to be substantiated by actual observation.

 

Bingo. Incandescents are better for reading, full stop. I don't give a $#!+ what anyone claims about energy or CO2, banning incandescents is a despicable and indefensible act of tyranny, like drug prohibition. In a country like the USA where people's reading skills are so abysmal, forcing people to switch to lighting that makes it more difficult and even unpleasant for kids to read is an atrocity.

 

The first phones were poor, but the government did not outlaw the alternatives.

The first computers were poor, but the government did not outlaw the alternatives.

The first cell phones were poor, but the government did not outlaw land lines.

But that is exactly what they did to lighting.

Government is the enemy.

 

I also bought one of the newer technologies of LED bulbs, that claims to give off "warm white light", in contrast to the bluer color of light the LED bulbs typically give off. While it was certainly much better than the ugly light from CFL bulbs, it still did not quite compare to traditional incandescent bulbs. I think the reason why is because these yellow colored LED's are not really full spectrum, as you can see in the diagram below. There is bluish light and yellow light, but not much in between. So it still does not quite look right.

 

For the price of two "60 watt equivalent" LED bulbs, I bought a whole case of 100 watt incandescent bulbs.

"PAR" (parabolic) incandescents were design specifically for can lighting.

The problem is not the performance of the LED vs incandescent. I'm sure each has its niche. What I resent is government forcing me to buy something I don't necessarily want.

Government is the enemy.

 

What I resent is the horrible disgusting light from fluorescent lighting, whether it is overhead tubes or CFL spiral bulbs. Working under fluorescent light strains my eyes, and it is difficult to concentrate under it. I can barely even read a book under CFL light. While not all people are bothered by this light, a substantial portion of the population is. I would even go so far as to choose a lower paying job, so long as it is not under fluorescent light.

As all the incandescent (and halogen bulbs too!) become banned, this will leave me and many others with only one other practical option: LED lighting. Unfortunately LED bulbs have many problems right now. As far as I am aware, no LED bulb is currently commercially available that can replace a normal 100 Watt bulb. The highest wattage of LED bulb available (that can fit into standard sockets) is 15 Watts, which gives out only as much light as a 60 Watt incandescent bulbs. This is just not bright enough to light many rooms, or for reading. And even this 60 Watt equivalent LED bulb will not fit into most of the lamps or ceiling fixtures I have because of the wide diameter of its cooling fins. That means I have to buy more lamps to light the room. In other words, one essentially needs to buy three 8 Watt LED bulbs to replace a normal 100 Watt bulb!

One more thing, Most of these LED manufacturers are very misleading about the light output from their products. In a typical lamp, each Watt from an LED bulb is the equivalent of only 4 Watts from an incandescent bulb. In other words, it would take a 25 Watt LED bulb to put out the same ammount of light as a normal 100 Watt incandescent bulb. Currently there is no commercially available LED bulb that has the equivalent light output of a 100 Watt normal bulb, although GE has announced it will soon offer the GE Energy Smart® LED, which is 27 watts. It has not said how much this will cost, but likely it will be around 35 to 40 dollars each.

 

The first phones, computers and cell phones did not consume four or five times as much electricity as the newer alternatives. The extra electricity being used did not scale up with the whole population of America to amount to millions of extra barrels of oil being burned every day to provide the juice. The use of older phones and computers did not negatively affect our balance of trade or adversely affect the climate.

As usual, you have no idea what you're talking about.

Pure tea-party insanity.

 

The plain truth is that neither CFL's nor even LED's can put out the same type of light that comes from incandescent bulbs.
Theoretically, it should be possible to design an LED lamp that puts out a full spectrum light distribution that closely matches incandescent bulbs. But in practice this is not the case, and such LED replacement light bulbs are not being commercially produced. Red and green LED's are already common place, and it is exactly these frequencies that the "warm white" LED lamp is missing. As it is, warm white LED light seems to approximate incandescent light, but the color contrast in a room is much more dull, and it looks just a little off.

There must be some other way of encouraging LED lamps without essentially banning incandescent bulbs. Why can't the government just offer subsidies for the production of LED bulbs? Couldn't there be some way of discouraging people from buying normal light bulbs without banning them? One idea would be to make people pay for a set of 5 incandescent light bulbs up front, but they would only get one. Then they would have to go back to the store with the receipt every year after to get the rest of the 4 light bulbs. This would still allow people who absolutely hate the newer types of light to keep their beloved incandescent bulbs, while nudging the lazy people who do not really care to buy other bulbs.

In any case, the government should be encouraging LED bulbs, not CFL's which contain environmentally polluting mercury. If people want to buy CFL bulbs, and use them in the appropriate settings, to try to lower their electric bills, let them. But do not encourage it.

 

PHP:

It seems that a 20 Watt LED bulb is now available. For 67 US dollars (not including shipping) you can buy this gigantic sized device. http://www.ledglobalsupply.com/par-led-bulbs/20-watt-alt-par-38-led-light-bulb-white-120v/

Yes, it will screw into an ordinary light socket, but will it may likely not be able to fit inside most of your lamps.
I doubt it is really the equivalent of 100 Watt bulb, like it claims (probably more like an 80 Watt bulb).
But will you actually be helping the environment by placing an order for this thing? How much energy does it take to transport a single bulb (it is quite heavy) in the mail to your individual house? Probably more than you realise.

 

Philips has now made commercially available a 17 Watt LED bulb that can replace bulbs in ordinary lamps (they are not directional flood lamps). Home Depot is selling them for 156 dollars each through their online store. That should put out about as much light as a 75 Watt regular incandescent bulb, and this is exactly what the packaging claims; credit to Philips for actually being honest about their product. It has a rather unusual looking design:



I bought some 8 Watt LED bulbs. Despite appearing very bright when one looks directly at the bulb, they do not really put out a sufficient ammount of light by themselves to provide decent lighting for a room. Remember, they have only a hemisphere of light output, in contrast to a normal bulb that is a full globe (sphere). So they can paradoxically be "brighter", but still have a lower light output.


I would have bought higher wattage bulbs, but it is difficult to find LED globe bulbs over 10 Watts. Virtually all of the 17 Watt ones are directional flood lights, not really suitable for ordinary lamps (because they shoot all their light upwards at the ceilling, and do not fit into most lamps because of the wide diameter for their cooling fins)

 

There is also the so-called "corn cob" shaped LED lights. These have the advantage of being able to put out light more evenly in all directions.



They are probably best used behind a lampshade, because of they are not very aesthetically pleasing to be vissible directly.
But the higher wattages do tend to be more expensive, and rather difficult to find a store that sells them. A 15 Watt version sells for 63 US dollars, while a 20 Watt version sells for 80 dollars.

Here is one consumer's review:

"I actually couldn't get on with it; I found that it was too harsh to look at. And after about a week of use the light output dimmed down to about half of what it was originally, and it was a weird kind of greenish-yellow light... that I found just didn't illuminate the room properly. The lights themselves looked really bright in the fitting, but when you looked at an object that was red or green, it just looked like it wasn't being lit properly... so it was the most peculariar thing. I suspect it's probably because these LED's have a couple of very narrow spectral peeks, so they're probably producing a lot of very blue light, and a lot of very yellow light, and to our eyes that light looks white. But when you shine that light on something green or red, it doesn't illuminate it, it's just absorbed.

"So what conclusion are we going to draw from this experience? Well, for one thing, I just didn't like the light quality with these bulbs; it was unnatural colored light when it was switched on. The color of the light was just weird and made everything look strange. After about a week the LED's lost half their brightness, probably because the LED's are being driven way beyond their tolerance, or perhaps they're just inferior quality anyway, and don't have the lifetime they should. When these were in operation there was a conspicuous smell of electrical burning which I don't take as a good sign of electrical devices working properly...perhaps more importantly, it shouldn't smell like it is just about to explode... I think they're a safety hazard. I would be concerned that this was going to catch fire and burn down my house.

It's supposedly a 5 Watt unit, providing the illumination of a 60 Watt bulb. Unfortunately, it doesn't do what it says. I certainly won't be buying any more of these for my home."

http://www.youtube.com/watch?v=BKUEgnLpeQo

 

I think LED's in many situations can save on money.

Your concern about shipping them is misfounded. How do you think all that stock gets to the shelves in stores? It doesn't go by electric car that's for sure. And it's better to order on demand as it uses less fuel than shipping a whole bunch of stock, not all of it gets bought, and then has to be shipped yet again away.

 

There is now a 24 Watt LED becoming available in stores, selling for 40 US dollars.
I am surprised such a high wattage of LED has become readily available, and that its price is not much higher.
But this is a directional floodlight. And the 24 Watt version of this lamp only comes in the bright white version. The cool white version is only availabe up to 18 Watts. The reason for this is probably that the "bright white" version is less efficient because it has to go through a yellow phosphor coating, so it requires more power. Still, the lumen rating suggests that the higher power is enough to make the warm white version overall a little brighter.

I have actually tested this 24 Watt LED and for some reason it just does not seem to give out as much light as one would expect from 24 watts from an LED light. The packaging claims 1300 lumens (which should be remembered is from a directional light source, so cannot be directly compared to the lumen output from a spherical bulb. The 18 Watt cool white LED, which is otherwise identical, is rated at 1150 lumens, so we can see that the light efficiency for the "warm white" version is somewhat lower. (In other words, a 24 Watt cool white LED lamp would put out more light)

The light quality is actually very decent. It still does not render as much color contrast to objects as halogen lamps, but it does have a noticibly more natural light quality than other warm white LED bulbs. I am not sure why this is. I tested 20 of these LED's out on the patio at night. It was almost like being in natural daylight. These things are going to help people that suffer depression in the darker winter months.

But although the color and quality of the light seemed good, for some reason my eyes just had a little trouble focusing under this type of light. It was not the brightness of the light, it was something else. When I began reading something under the light, the letters just did not seem to be as clear. I am really curious as to why this is. It was not a very noticible affect, but if one is reading a book under these lights it might be an issue to some. It could just be me.

http://www.homedepot.com/webapp/wcs...talogId=10053&productId=202670526&R=202670526

 

"The first phones, computers and cell phones did not consume four or five times as much electricity as the newer alternatives."

Taxcutter says:
Have you ever looked at an old Western Electric rotary-dial phone? It has big, heavy electromechanical coils in it. They are big to withstand high current operation over a prolonged period of time. They were low voltage systems and that entails a high percentage of line losses. They were enrgy hogs.

Ever see a IBM System 360? The standard of the 60s and early 70s. It required seven tons of cooling to keep it from cooking itself. That meant it was consuming a vast amount of electricity. Where else would all that heat come from? The Liebert product line (still making computer coolers today) was built on keeping that old energy hog operating. My PC, which has the computing power of a building full of System 360s gets by on a 1 kW power supply.

Ever look at even 1990s-vintage cell phones? About the size of a man's shoe. They had huge batteries and needed them because they consumed enormous amounts of power. My cell phone is tiny (even though battery tech hasn't changed) and gets charged once a week (a one-hour process).

C'mon man. You gotta do better than that.

 

Different types of lights have very different light spectrums. The spectrum of a particular type of light affects not only what color it appears to be, but also how other colors appear under the light. Below is a comparison between three types of light bulbs: normal incandescent, normal incandescent with a "Reveal" filter, and white LED.




As can be seen, for the white LED's there is a narrow spike at 460 nm (blue light), and also a wide band in the yellow-green spectrum that expands into the orange and somwhat towards red.

Here is the spectrum for Reveal bulbs, which use a neodymium coating to selectively filter out some of the yellow light. Unfortunately, as can be seen in the graph, this filter is not ideal. Some of the blue light also gets filtered out, and a little narrow peak is left in the yellow-green part of the spectrum. The yellow that gets filtered out is a little more towards the orange side than the green side.


I find it somewhat ironic that Reveal bulbs try to filter out the yellow to make the bulb seem more "blue" to the human eye, while "warm white" LED's add a phosphor to add yellow light because it would otherwide be to blue. Perhaps it would just make more sense to combine blue LED light with incandescent light? That might give the fullest light spectrum in the most economical way.

 

Here you can see the difference between regular incandescent bulbs and sunlight:


As you can see, sunlight is a wide full spectrum hump centering on yellow light. Incandescent light is also full spectrum, but gives off much more "warm-colored" light (red, orange, yellow) and not as much blue light. Here again, you can see the comparison between incandescent and white LED:

Incandescent has much more red-orange light than LED.

 

Halogen bulbs give off similar light to incandescent, but because of the higher temperature the distribution is shifted a little more towards the bluer side the spectrum. For this reason, halogen bulbs appear "whiter" than incandescents.



The point of all these spectral graphs is to show that one type of light source can never really substitute for another type of light of light source. Each light source gives off its own unique spectrum. It is much more complicated than just "color temperature".

 

Putting it in a nutshell: In most cases both LED and CFL bulbs are a bad deal for the consumer.

Thanks for jamming a bad deal down our throats, government.

 

And the spectrum for fluorescent lights (including CFL's) is just awful. It is not continuous at all, which means colors often look wierd under fluorescent light, and it also has an eery pink or greenish tint.



This graph does not even show all the harmful UV that leeks out of the spiral bulbs. All this UV actually causes yellowing of the plastic base over time.





Here's the spectrum from an incandescent light bulb for comparison:


As you can see, light produced by incandescence is full spectrum, and thus does not have any sharp lines, just like natural sunlight.

 

One of the other environmental considerations for LED lighting is the aluminum used in the cooling fins.
Some of these heat sinks / cooling fins can be quite heavy, especially for higher output LED lights.

This aluminum heat sink is for an 80 Watt LED chip, and weighs 1.8 kg:


This aluminum heat sink for a 100-120 Watt LED chip weighs 3.8 kg:
http://www.made-in-china.com/showro...a-LED-Heat-Sink-Cooler-MG-S-100W-120W-1-.html
while this one (100 Watts) weighs 3.4 kg:
http://www.made-in-china.com/showro...na-LED-Heat-Sink-Radiator-MG-F-100W-B-4-.html

So how much energy does it take to produce the aluminum for these heat sinks?
Because aluminum smelting involves passing an electric current through a molten electrolyte, it requires large amounts of electrical energy. On average, production of 2 lb (1 kg) of aluminum requires 15 kilowatt-hours (kWh) of energy. Just the cost of electricity represents about one-third of the cost of smelting aluminum. All these heat sinks are made in China, where most of the electricity comes from dirty coal fired powerplants.

The other major ingredient used in the smelting operation is carbon. Carbon electrodes transmit the electric current through the electrolyte. During the smelting operation, some of the carbon is consumed as it combines with oxygen to form carbon dioxide. In fact, about half a pound (0.2 kg) of carbon is used for every pound (2.2 kg) of aluminum produced. This carbon is released as carbon dioxide into the atmosphere. For every one pound of carbon consumed, 3.6 pounds of carbond dioxide is created.

This is why it would be so important to recycle the aluminum heat sinks for LED lighting.