LEDs - Do the Benefits Outweigh the Cost?

7x7 asks: "We keep hearing about the latest and greatest thing to come out of LED technology, and every article seems to give an over-view of the topic. How LEDs consume little electricity and last a long time, etc. However the manufacturing process involves super hot ovens and expensive componants. Do the requirements necessary in the manufacture LEDs and LED componants out-weight the requirements for standard bulbs over 10 years? One LED light can last ten years, but contains dozens of LEDs. Has anyone seen or performed an evalutation to see if the trade-off is really anything to speak of?"

Comments

Previously on Ask Slashdot

[Nighttime]

Previous Ask Slashdot discussions on LED lighting, LED Light Fixtures for the Home? and Which LED Flashlight Do You Use?

What do you want do?

[obtuse]

As always, it depends on the use.

I haven't seen anything about manufacturing costs, so maybe I'm not answering your question, but in use:

In traffic lights, a burned out bulb is a hazard, and expensive to change.

Brake lights and taillights are dangerous to lose, and they get shaken around. That's why in many cars if your brake or taillights go out, your dash lights go out too as a reminder.

Flashlights are typically low temperature bulbs where incandescents are more inefficient, especially after the battery voltage starts to drop off. Besides, they get dropped, so LEDs are a win there too.

Fluorescents are the most effecient, but for household lighting I don't like their color or sixty Hertz visible hum. (Any specific recommendations for a compact fluorescent that has a good color & a nice ballast that doesn't flicker sixty times a second?)

The LED geeks know LEDs aren't always better as far as power consumption goes.
http://www.pioneernet.net/optoeng/LED_FAQ.html#Q7
http://misty.com/people/don/lede.html

I saw a nice use of LEDs in a remote campsite. There were solar collectors on the roof of the bathroom, and little banks of a few LEDs that lit the bathrooms at night.

An LED seems smaller, but the incandescent in a mini-maglite puts out much more light than a white LED of the same size.

LEDs are inefficient too.

[pr0ntab]

A high-efficiency red LED puts out about 2.5 mW of luminous energy in its emission band, and consumes 120 mW of power. That's 3% efficiency. The rest is dissapated as heat. Incidentally, that's why LEDs have a large footprint (the luminous area is very small); so the heat can spread out and the junction characteristics don't change. Incandescents emit light energy outside the visible band, unlike LEDs. This is where most of the power goes, not heat. Thus, incadescent lights achieve about 15 lumens per watt, flourscents get about 50 per watt. Contrary to popular belief, LEDs are in between, the high efficiency models get about 25 lumens per watt.

The most efficient LED right now is %32. You can't buy these yet... they will be used in lights that operate like flourescent lights since they emit UV. This will be the ideal, long-lasting but low power light source.

LEDs are not economical when a flourscent light with electronic ballast can be used in the same situation. In scenarios where the extra electronics required by a flourscent light are too bulky or not enough power is available- this is where LEDs shine. That is why they are the flash-light champs.