Current state of the art LED's are, oops, they forgot to tell you, florescent. Anyway, they are very close to a CFL in total efficiency, as in viable light to power used. The 8 foot industrial tube is still the champ. BUT, as LED's are directional, you can use fewer watts to get the same effective illumination on a surface for most applications.
They also forget to tell you that based on hot-wire equivalent, which is how we measure bulbs, no bulb can exceed about 35% efficiency because we do not see all the light in the visible spectrum, we see only three narrow bands. A CFL is between 16 and 18 %, so half way to perfect. Only a sodium is more efficient as it is not wide band white light.
They also forget to tell you the total carbon footprint of manufacturing a LED assembly compared to traditional. Even shipping is higher ( they all come from China) because they are much heavier. Massive aluminum heat sinks. Ever notice how much power smelting aluminum takes?
Me, I have eliminated most of my florescent bulbs because I don't like the hum, flicker, rapid reduction in output, and now a disposal problem. I still use A base incandescent bulbs for light quality. Of course, in the winter, they are very efficient as I am using all that heat. I really like my LED ceiling cans as instead of a vented, heat leaking 75W hole in my ceiling, I have a sealed can using only 12W and get more actual light on the counter. I like my 1W LED bulb I leave on outside because my wife believes our dogs need extra light to see. ( they see fine at night, but never mind). I like LED's for spot task lighting as they can be much closer to you without frying your head. Being closer, far less total light is needed.
Conclusion? "It depends"
CFL bulbs contain mercury and are only a stop gap solution.
Philips makes a LED bulb that puts out a luminescent intensity of 800 lumens at 2700K.
It dissipates 12.5 watts and Home Depot sells them for $26.95
These use a Edison E26 mount (same mount as a regular incandescent bulb).
Philips has a new model that puts out 1100 lumens at 2700K
They dissipate 17 watts - but Home Depot wants $45 for them.
BTW: colour temperature is one spec to to look at.
2700K has about the same warmth as a regular incandescent bulb.
3000K is white light
3400K is starting to be a ghostly blue.
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Philips makes a LED bulb that puts out a luminescent intensity of 800 lumens at 2700K.
It dissipates 12.5 watts and Home Depot sells them for $26.95
These use a Edison E26 mount (same mount as a regular incandescent bulb).
Philips has a new model that puts out 1100 lumens at 2700K
They dissipate 17 watts - but Home Depot wants $45 for them.
BTW: colour temperature is one spec to to look at.
2700K has about the same warmth as a regular incandescent bulb.
3000K is white light
3400K is starting to be a ghostly blue.
.
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The main reason why I like LEDs is for the lifetime. Yes, their efficiency next to the best CFLs and fluorescent lights is similar, but in applications such as MR16 halogen reflectors...I use some of these and I forever felt like I was changing bulbs to the point where I got fed up and didn't even bother replacing them. I then took the fitting apart and converted the entire thing to LEDs. A couple of years later and they are still going strong.
As Uunderhill says though, you really do need to get 2700k LEDs if you want things to look nice next to incandescents.
As Uunderhill says though, you really do need to get 2700k LEDs if you want things to look nice next to incandescents.
Lighting is not a straightforward issue, since the human eye has a variable response to frequency, just as has the human ear. The Lumen is a measure of visible light, lumen measurements reflect the varying sensitivity of the eye, raw light power is expressed as radiant flux.
CFLs were still recommended as the leading technology for domestic use by the US Department of Energy as recently as 2011.
While fluorescent tubes remain high in the efficiency stakes, it must be remembered that they are tubes, and overall efficiency depends on the luminaire.
Without entering into a discussion of the issues any deeper than that, LEDs are approaching the best efficiency achievable by any means and with more pleasant colour rendition. They will almost certainly achieve an efficiency unobtainable by any other means, with superior colour rendition, at some point in the future, if they haven't already in laboratory conditions.
As the efficiency of LEDs improves, the heat evolved decreases, so the environmental cost of producing heatsinks can only be expected to decrease.
LED replacement lifetime is better than any competing technology, and LEDs are being adopted for street lighting, for this, if for no other reason.
LEDs are all-round the best technology for flashlights, being mechanically robust.
Cree are probably the leading developers of LED dies.
CFLs were still recommended as the leading technology for domestic use by the US Department of Energy as recently as 2011.
While fluorescent tubes remain high in the efficiency stakes, it must be remembered that they are tubes, and overall efficiency depends on the luminaire.
Without entering into a discussion of the issues any deeper than that, LEDs are approaching the best efficiency achievable by any means and with more pleasant colour rendition. They will almost certainly achieve an efficiency unobtainable by any other means, with superior colour rendition, at some point in the future, if they haven't already in laboratory conditions.
As the efficiency of LEDs improves, the heat evolved decreases, so the environmental cost of producing heatsinks can only be expected to decrease.
LED replacement lifetime is better than any competing technology, and LEDs are being adopted for street lighting, for this, if for no other reason.
LEDs are all-round the best technology for flashlights, being mechanically robust.
Cree are probably the leading developers of LED dies.
Saw some 450 L LED's in the store yesterday for $8.50. Now that I can deal with.
Robust. I think of my spelunking days and how many extra bulbs we carried. Minimum two lights each, 2 bulbs for each, a glow stick for good measure and we still had head-lights.
Great where the cost of replacing the bulb exceeds the cost of the bulb. I just hope for street lights they pick a very low temp equivalent, like 2300 degree light. Us old farts do not like blue light at night as the glare makes us blind. Down with HID and Zenon headlights!
Last report I read a lab had a white LED at 22%. As 32% is the theoretical max, it is getting darn close. The only way to get closer is to use three different bands and not generate any mid band output and then further reduce the IR. I doubt we are going to see that any time soon. Darn physics. I don't think that included the power supply.
Robust. I think of my spelunking days and how many extra bulbs we carried. Minimum two lights each, 2 bulbs for each, a glow stick for good measure and we still had head-lights.
Great where the cost of replacing the bulb exceeds the cost of the bulb. I just hope for street lights they pick a very low temp equivalent, like 2300 degree light. Us old farts do not like blue light at night as the glare makes us blind. Down with HID and Zenon headlights!
Last report I read a lab had a white LED at 22%. As 32% is the theoretical max, it is getting darn close. The only way to get closer is to use three different bands and not generate any mid band output and then further reduce the IR. I doubt we are going to see that any time soon. Darn physics. I don't think that included the power supply.
The theoretical limit of luminous efficiency for a white LED is 38.1~43.9%. This depends on the exact hue.
100% conversion of electricity to light yields 683 lumens/Watt @ 555nm.
See Wikipedia - luminous efficacy.
100% conversion of electricity to light yields 683 lumens/Watt @ 555nm.
See Wikipedia - luminous efficacy.
One thing that's bugged me about these non LED, energy saving fluorescent bulbs is the noise! You can hear the 50Hz derived buzz they give off. I was having yet another one of those head scratching hum hunting sessions once, only to discover it was the bloomin' lightbulb.
I'm certain filament bulbs didn't do that.
I'm very likely to move to LED, or somehow return to filament for rooms where I may listen to hifi.
Yeah! And I'm running class A! I am an enemy of the environment! No really. I'm terrible. Sometimes, I charge my phone! There, I've said it.
I'm certain filament bulbs didn't do that.
I'm very likely to move to LED, or somehow return to filament for rooms where I may listen to hifi.
Yeah! And I'm running class A! I am an enemy of the environment! No really. I'm terrible. Sometimes, I charge my phone! There, I've said it.
LEDs arent always silent either, but that's only if you're using PWM dimming as the inductor can sing at the PWM frequency. At 100% duty cycle though there is no noise.
I have heard filament lights buzz. It is usually not too long before that little quire pop.
When I re-did my office, where I now sit, replacing the florescent lights was a big hit on the list. Can't stand the noise.
Florescents also make food look bad. Eateries stick with incandescent for that reason.
None of my LED lights make noise so far. I have about a dozen of different brands.
I am SO glad for the higher refresh rates of computer displays. The old 60 Hz tubes I could actually see. Now we have florescent flickering at 120 with an LCD mask at 80. I wonder if the beat is some of what gives me so much eye strain? LED lit monitor?
I replaced most of my lights with warm-white LED, I have the LED's close to the ceiling pointing up, so all I get is reflected light, very nice and easy on the eyes. I have a total of 24w LED in my living room, used to have 300w of halogen, light output may be lower, but dispersion is better.
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We have LED lights in the bedroom. Their filter starts buzzing when my wife plugs in the charger for her notebook into the same outlet. I am going to open now that device and glue the coil by epoxy.
Just for a test, what happens if you plugged the charger into a good line filter?
Let us know how potting it works and which brand bulb.
Let us know how potting it works and which brand bulb.
After seeing PWM controlled LEDS on an oscilloscope, and on a video camera, I've replaced my desk lamp with one of those highly reliable, cheap as ever (I've got a stockpile), wire-inside-a-vacuum-tube-thingies:
Its on a variac and turned on 24/7 so its going to last a loooonnnnnggg time as long as I don't knock it around too much, its also extremely easy on the eyes, being 25 watt and on a variac, so it gives me exactly the right amount of light that I need when and where I need it. It would be better with a 60 watt globe though.
I hate PWM controlled LED's but current controlled leds are fine, I also hate Flourescent, but I don't mind some Flourescents, it depends on the brightness (40 watt is fine) and the colour temperature, I generally prefer 7000k aquarium lamps over the generic 6300k daylight tubes. Maybe I'm really a fish at heart? Gee I don't know anymore, all I know is LED light is too intense and directional for me to use or like it on my desktop here.
Its on a variac and turned on 24/7 so its going to last a loooonnnnnggg time as long as I don't knock it around too much, its also extremely easy on the eyes, being 25 watt and on a variac, so it gives me exactly the right amount of light that I need when and where I need it. It would be better with a 60 watt globe though.
I hate PWM controlled LED's but current controlled leds are fine, I also hate Flourescent, but I don't mind some Flourescents, it depends on the brightness (40 watt is fine) and the colour temperature, I generally prefer 7000k aquarium lamps over the generic 6300k daylight tubes. Maybe I'm really a fish at heart? Gee I don't know anymore, all I know is LED light is too intense and directional for me to use or like it on my desktop here.
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I agree. Incandecsence is the best light. You want to save on electric bill, turn the heater setting down a few degrees. (AC setting up a few degrees) Focus your effort where it really counts as far as energy usage and don't deny yourself proper lighting.😉 Besides, there is nothing toxic about a piece of tungsten wire inside a glass bulb with an aluminum base and silver solder.
Except it is not a vacuum tube. If under 40W, it is full of dry air. Over 40 usually nitrogen.
I totally agree the light quality is better and the color is easily adjustable. I do like LED when a reading light is just a foot above my head as it is much cooler on my no longer well covered head.
Another place won't work in in my spring arm lamps because they are too heavy for the springs.
I too have a stockpile of good old 60W bulbs.
I totally agree the light quality is better and the color is easily adjustable. I do like LED when a reading light is just a foot above my head as it is much cooler on my no longer well covered head.
Another place won't work in in my spring arm lamps because they are too heavy for the springs.
I too have a stockpile of good old 60W bulbs.
Yes, and recorded music is very bad for the ears. You can go deaf from listening to MP3s, even at low volume. Most of the young people I know are deaf already, if the stuff they listen to is anything to judge by.
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