LED Light Fixtures for the Home?

HBergeron writes "Despite some exhautive searching I have able to find very little about LED based light fixtures for the home. There are some in marine use, and a spare handful of others come up on a Google search but from all I have read on Slashdot I have to believe there are more out there. I am in the final stages of a home remodel and would very much like to use 'the lighting source of the future' (tm) in a number of places. For one, the bedroom, LEDs could make a nice bedside sconce/reading light, and a red/white option could be just the like for those late night stumbling across the room expeditions. A vanity light seems like another good place. Not to mention energy and bulb replacement savings." While these may not be economical for most people, I'm sure there are a few folks out there who have put these new lights to the test. How well did they stack up to the use of traditional filament lights?

Comments

LED are as effcient as Incandesent

[master_xemu]

White LED lights actually are only as effcient as regular incandecset bulbs. If you are looking to save money you are better off going with CF, if you want effciency go with metal halide.

Re:LED are as effcient as Incandesent

[eXtro]

That's not true. The heat in an incadescent light bulb is a sign of it's inefficiency. You want energy emitted in the visible light portion of the electromagnetic spectrum, not the infrared.

Re:LED are as effcient as Incandesent

[Meowing]

Yep, it is true that white LEDs aren't yet any more effiecient than incandescents if you want general room lighting.

They do currently have some advantages if you want controlled directional lighting, but that does limit the applications quite a bit. A comparative chart of energy vs. light output can be found here.

At present, fluorescents are much more energy efficient than other practical alternatives for home use. There is still the issue that they contain mercury, though.

A couple of places to check out...

[Anonymous Coward]

LED light bulbs

LED brass desk lamp

Several models to choose from

DC Voltage

[Syris]

LEDs require a DC voltage and current to run(typically ~3V and 20mA) as opposed to the 120V AC voltage wired to throughout your house.

You would need some converters as well as LED driver chips to run the 'bulbs' optimally.

This is all doable; it's just a lot easier to use one of the many, many, many types of incandescent bulbs.

Not as efficient as some claim

[photon317]

I did some research on this a while back, with the intent to purchase or build some LED lighting systems. As it turns out, for practical, normal household use, LEDs aren't as efficient as some would have you think. You're better off with some form of flourescent lighting. Where LEDs shine is in spot-lighting situations - such as desk lamps, or small spotlights that go under the bottoms of cabinets to light up counters, and that sort of thing.

They provide more light per watt of energy consumed to a small focused area than other technologies, which spread their light in all directions and are masked/reflected to give light to only one direction. But for a main light source illuminating a room in all directions, they're somewhere in the same neighboorhood as incandescents in efficiency, and soundly beaten by flourescents.

LED only good for low power apps

[linuxwrangler]

As other posters have mentioned, the lumens/watt for LED is about the same as for standard incandescent. There are a couple of places where LEDs shine (so to speak).

One is in very low power systems where the LED's output/watt remains fairly constant but the lumens/watt for incandescent is extremely poor. The PALlight flashlight can run in "off" which is actually "very dim" mode for over a year with no problem.

Another is where you want long life and/or color such as in signal lamps. To explain: the lumens/watt for incandescent goes up dramatically with higher voltage but the lamp life decreases in a similarly dramatic fashion. That's why the bulbs on small flashlights where available power is a limiting factor often last only 4-6 hours compared to a standard bulb at nearly a thousand. Signal lamps are at the other end of the spectrum - they need to last a very long time but do so at the expense of efficiency. In addition, much of the light they produce is filtered out to get the necessary green, yellow or red. LEDs produce just the color you want so there are no filtering losses and they don't need to run at reduced efficiency to give long life.

LEDs beat flourescent where you need point-sources of light for focused applications like headlights. Some LEDs are now starting to get somewhat above the efficiency of incandescent and you may see them soon in auto headlights (I've seen a couple of prototypes - tiny led and big-a** copper heatsink).

Finally, LEDs are good in rough-service and high-vibration applications.

For general use around the house flourescent is far, far more efficient and currently far less expensive (last home LED light I saw was well over $100) and the new flourescents put out a very nice light - far nicer than any LED lamp I've seen. With the exception of a reading lamp my wife owned before we got married, every light in our house is flourescent and it really does make a difference on the power bill.

another place...

[Dancing Tree]

www.ledtronics.com

They have lots of light bulbs, strips of leds, etc. as well as a bunch of other neat items (solar lantern, flashlights, flashing safety vests). Some of the household items simply screw into a light socket, others would require some sort of transformer.

Laws of physics

[master_xemu]

The laws of physics show that semiconducter LED technology can't achieve a better than 25% electrcity to light conversion, which would be under flourecent and about half metal halide. Currently white LED's are about 12% efficient.

Re:Laws of physics

[rcw-home]

But do they convert the other 88% to heat the way that incandescent bulbs convert 90% of the electricity they use into heat with the 10% converted to light as almost a byproduct?

Like anything else they follow the law of conservation of energy, so yes. BTW, incandescents are more like 3% light, 97% heat. Either way the light portion turns into heat when something absorbs it. Heat is an amazingly dense form of energy storage, so one tends not to notice it so much, but all other energies are slowly turning into it (entropy).

Color Kinetics

[Das Kamikaze]

Color Kinetics have a number of LED light product lines, both professional and consumer. Their consumer branch, Sauce makes an assortment of wands, flashlights and nightlights, while their professional arm has done a number of Huge installations.

As for prices, I'm sure if you have to ask, you can't afford it...their 4 color intelligent nightlight looks relatively cool for $8.

Re:small applications

[pyite]

Yea, yellow is usually the last to be replaced (I know this because I do work at police departments and one of the departments' computer guy is a traffic detective). The reason is that it's not on very often and isn't as "important." LEDs offer excellent benefits for red and green though. They have faster response time, translating into more stopping distance at speed. Plus, they are brighter, and you can see it. And they save money in the long run because they don't need to be replaced as often.

I bought an LED bulb 2 years ago.

[stefanlasiewski]

On a whim last year, I bought an Ledtronic 9-led 4500K Incand White bulb
at a fire sale at my local alternative energy shop. It uses
approximately 0.6-1.2W of power, and produces light equivilant to a 15W
incandescent bulb.

But that said, it's sitting here on my desk, not in a socket. Why? When you turn it on, the light flickers and
whines (my guess is it's about a 60-hz flicker/whine, like an old TV);
and I have not found a good place to put such a dim bulb (perhaps when
I install my outdoor lights or build the shed in the back).

But this is an early generation bulb, so I expect the flickering to go away with a later generation.

I built them myself and they are great.

[jakedata]

I have an off-grid camp and desired safe and efficient lighting. I loathe fluorescent light.

So I have a small (300 ma) solar panel charging a 12 Volt gel cell that I salvaged from a UPS.

Rather than use resistors or a dc-dc converter, I wired the LEDs in series. I made strings of 5 LEDs and wired the strings in parallel. (think christmas lights) Peak voltage on my circuit can be > 14.8v

Hints:
The light was extremely white/blue so I made some yellow strings and mixed them in. Cheaper that way too.

I used a cheap wirewound potentiometer as a dimmer because it was too bright for night reading.

I made the electrical connections into a self-supporting frame for the LEDs rather than using a backing material. That means the clear LEDs and fine wires disappear into the background. When it is off it is nearly invisible.

The LEDs I used (Hewlett packard, purchased from Newark Electronics) are extremely focused and directional. It took some careful aiming of the individual elements to get a good spread. You might consider a diffusor.

Good luck, and I will be happy to answer questions if you have any.

Next time I make some, I am going to make seperate red, green and blue circuits so I can tune the color balance.

-j

Not LED's, but we like our Microsuns

[dpbsmith]

Not LEDs, but I thought I'd mention that we currently have three Microsun HID metal-halide lamps in our house and are very happy with them.

Microsun makes table and floor lamps that are nice-looking pieces of furniture, mostly of wood. Not cheap but not out of line for "nice furniture." They incorporate a "gearpack'" which holds a 68-watt E17N metal-halide HID bulb and two conventional 25-watt incandescent bulbs.

The company claims "more than 300 watts [sic] [sigh...] of crisp white light, yet uses less than half the energy to do so." I think the claim is reasonable. The bulb package, annoyingly, does not state the light output in lumens, but such bulbs typically seem to have an output of about 5000 lumens. (The 25-watt bulbs, of course, don't add very much light but are just there to warm up and smooth out the spectrum).

That is, of course, not nearly as energy-efficient as fluorescent. However, most of the compact fluorescents we've tried really have fairly unpleasant color balance AND just don't put out much light.

These lamps put out a LOT of light and the color balance is quite pleasant. And they just look "normal," small bright sources of light inside a lampshade that light up the room just the way traditional lamps do.

Nothing revolutionary here, just nice, bright, ready-made, energy-efficient lighting with no "geekiness."

Physics of LEDs

[Spamalamadingdong]

The way LEDs work is by allowing electrons and holes to combine under conditions favorable for the production of photons. If a photon is produced, great! If not (say, an impurity traps the energy of recombination), the energy instead goes to vibration of the crystal lattice: heat. The same is true of semiconductor lasers.

It's pretty hard for a crystal of gallium indium phosphide to generate mechanical vibration (no piezoelectric effects that I know of, and no variation in the applied voltage to drive it) or EM at other wavelengths other than thermal IR at the temperature of the device (what quantum processes exist to produce photons at near-IR wavelengths?). So the answer is "You can bet on the remaining energy going to make the device warm."

More on Luxeons

[Andy Dodd]

Go to http://www.candlepowerforums.com/ - It's the closest thing you can get to a "Luxeon Star User Group" :) - There are a lot of flashlight modders there that use LOTS of Luxeons in their projects. People have started using Luxeons elsewhere, too. (One guy on the forums builds Luxeon-based replacement dome light modules using 1W white LS units + a DC/DC converter circuit he designed himself.)

Very little in the terms of line-powered lights, but people are starting to experiment (very carefully...) in that area.