LED myth busted

roid · Post by **roid** » Fri Sep 30, 2005 7:05 am

http://www.otherpower.com/otherpower_lighting.html

it seems that LED lights are infact NOT more efficient than normal household lightbulbs.

i always thought they were

* white LED--15-19 lumens/watt
* standard 100 watt incandescent--17 lumens/watt

But wait! What about all the white LED high-efficiency claims that are all over...including the claims that used to be on this site? Unfortunately, much of this information is incorrect. Comparing the efficiency of a white LED light with a compact fluorescent by measuring the intensity of a tiny spot within the beam does NOT give proper efficiency results. We got much of our data for efficiency claims from an article in Home Power Magazine (click here to see this testing article) and in literature from LED distributors. The problem? All of the light from our LEDs is concentrated in a 20 degree beam, while the incandescent and compact fluorescent lights were tested without fixtures...and most of the light they produced was never measured in the test, since it sensed only light falling on the sensor. It's OK to compare different lights by how brightly they illuminate a certain size area...but put a reflector behind the compact fluorescent and incandescent bulbs in the test rig and the data would change significantly. Therefore, while the LED lights in this test may illuminate a small area as brightly as other lights, they are NOT significantly more efficient.

woodchip · Post by **woodchip** » Fri Sep 30, 2005 8:07 am

Perhaps a better test is to see how many led's it takes to light up a certain sized room in comparison to one 100 watt light bulb.

De Rigueur · Post by **De Rigueur** » Fri Sep 30, 2005 8:21 am

you mean 'how many led's does it take to replace a light bulb?'

Ferno · Post by **Ferno** » Fri Sep 30, 2005 1:04 pm

well white LED's are relatively new to the market. It will take a while before their efficiencey raises.

It's not really fair to compare infant technology with something that's been around for years.

Jeff250 · Post by **Jeff250** » Fri Sep 30, 2005 2:57 pm

For arguing the instrinsic merit of the technology it isn't fair. But for the consumer it is.

Ferno · Post by **Ferno** » Fri Sep 30, 2005 5:02 pm

Kinda like how it's fair to the consumer to compare plasma TV's (when they were new) to CRT TV's, huh.

fliptw · Post by **fliptw** » Fri Sep 30, 2005 5:07 pm

Who'd be dumb enough to light a room with LEDS? I'm considering using them as a shelf light, but not for an entire room. How strong could the desire be to light a house with 4 9-volt batteries be?

woodchip · Post by **woodchip** » Fri Sep 30, 2005 5:45 pm

fliptw wrote:Who'd be dumb enough to light a room with LEDS? I'm considering using them as a shelf light, but not for an entire room. How strong could the desire be to light a house with 4 9-volt batteries be?

Missed the point. We were trying to compare the energy efficiency of led's to that of a regular light bulb by lighting up a room. In short in certain apps like tail lights or console lights, obviously the led's are superior over incandescent. Lighting up larger areas the regular light bulb is still king.

Mr. Perfect · Post by **Mr. Perfect** » Fri Sep 30, 2005 7:33 pm

Hey, the LEDs still have longevity on their side, right? Thos things last forever, even if they do dim some over the years.

Ferno · Post by **Ferno** » Fri Sep 30, 2005 8:18 pm

Mr. Perfect wrote:Hey, the LEDs still have longevity on their side, right? Thos things last forever, even if they do dim some over the years.

exactly.

in the end you'll be paying more for the lightbulb (replacement costs) than with the LED array.

roid · Post by **roid** » Sat Oct 01, 2005 12:24 am

well i was all into LED house lighting for a while ever since i saw the VOSPAD, mostly for the wild mood factor. the power saving was an extra feel good feature (save the planets yay!) that helped offset the cost factor, in my mind anyway.

i dunno, i'd have to work out how long a LED array light would take to pay for itself (compared to an equal lumens candescent).

heh... can-DESCENT.

Duper · Post by **Duper** » Sat Oct 01, 2005 2:43 am

Some of the high intensity LEDs that the engineers at work are outragiously bright. ... makes the eyes bleed. I don't know what kinda power consumption is involved...so..

*shrug*