LED'S VERSES INCANDESCENTS - Are they really more energy efficient ?

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Lumens per watt is a combination of efficacy and efficiency. It's important to not conflate efficacy and efficiency
The theoretical maximum photopic lumens per watt that can be achieved is 683 lumens per watt, and that is the lumens delivered by one watt of 555 nm monochromatic light. A contraption that converts one watt of electrical input into half a watt of 555 nm would produce 342 lumens to one watt of electrical power.

Even if we were to have a device that converts 100% of input to electromagnetic energy within the visible light spectrum, the lm/W varies depending on the spectral power distribution. A watt of deep red or near UV have much lower visual response, so the lumen would be lower.

LEDs (solid state fluorescent lamps) and low pressure mercury fluorescent lamps work similarly, yet differently. If you were to build a "fluorescent lamp" without the phosphor coating, it will glow sky blue due to visible components of mercury lines. The ordinary glass would block the UVC. The light given off by a normal fluorescent lamp is the combination of this sky blue light and whatever the phosphor blend gives off in response to UVC. Commercial LEDs use royal blue to excite the phosphor blend. The white light is a blend of yellow light from the phosphor blend and the blue that passes through.
 
ggunn said:
Well, yes; of course. Thank you, Captain Obvious. :D
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Probably sold to a lot of suckers though.

How did they ever survive many years ago when they often had to cook over a fire and sometimes after it was dark outside? Typical wood fire doesn't render all the light spectrum that well either:p
 
kwired said:
Probably sold to a lot of suckers though.

How did they ever survive many years ago when they often had to cook over a fire and sometimes after it was dark outside? Typical wood fire doesn't render all the light spectrum that well either:p
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They probably just experimented and found out by trial and error how long it took to roast a rabbit over an open fire, but that begs the question of how they kept track of the time.
 
ggunn said:
They probably just experimented and found out by trial and error how long it took to roast a rabbit over an open fire, but that begs the question of how they kept track of the time.
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Cell phones typically have timer apps in the initial setup :unsure:

:)
 
Frank DuVal said:
Ah HA! Cavemen had cell phones first! Then came the dark ages where all this technology was lost.... :LOL:
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Those words remind me of a talk I attended years ago that was given by communications mogul Craig McCaw. He started out talking about the needs of cavemen and what they had available to communicate. It seemed kind of weird at first, but everyone was hanging on to every word he said because he'd just invested $1.1 billion in Nextel.
 
mtnelect said:
As shown in the two images, LED light and incandescent light do not have the same characteristics and LED light, by virtue of the excessive amount of toxic blue wavelength light, is a low-quality light.
It should be noted that the reason that the manufacturers use blue wavelength light in LEDs is because this is how they increase luminous efficacy and reduce costs. The industry claims that LEDs are energy efficient are false because LEDs don’t provide the same high-quality spectral distribution as incandescent. If the manufacturers were to make LEDs with the same quality of spectral power distribution as incandescent, the luminous efficacy would be no better than incandescent.

More information to follow ...
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When I converted my modest size home to LED'S noticed the monthly electric bill went down over $10 a month. I prefer the 5K LED'S . Just wish somebody would decide if the higher K lamps are harmful. All manufacturers should be made to label ALL LED'S with their power factor to figure out accurate power consumption. Had way too many defective made in lack of quality control communist china LED'S & drivers so go out of my way to only use made in USA products.
 
garbo said:
When I converted my modest size home to LED'S noticed the monthly electric bill went down over $10 a month. I prefer the 5K LED'S . Just wish somebody would decide if the higher K lamps are harmful. All manufacturers should be made to label ALL LED'S with their power factor to figure out accurate power consumption. Had way too many defective made in lack of quality control communist china LED'S & drivers so go out of my way to only use made in USA products.
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Watts should be watts. If there is low power factor however the VA will be higher than watts. This is somewhat consistent though with labeling of any load that is not unity power factor. They usually have watt rating, volt rating as well as current rating - so one should be able to determine PF and VA with that information.
 
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