LED Light Fixtures for the Home? 101
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?
LED are as effcient as Incandesent (Score:3, Informative)
Re:LED are as effcient as Incandesent (Score:3, Informative)
Re:LED are as effcient as Incandesent (Score:3, Informative)
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 [rawthought.com].
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.
Re:LED are as effcient as Incandesent (Score:2)
There is still the issue that they contain mercury, though.
That, and they flicker and give off a totally unnatural colored light.
Re:LED are as effcient as Incandesent (Score:2)
Wouldn't it be possible to make them work at 180Hz instead of 120 (am I wrong about these numbers?)
No doubt it would be possible to run flourescent lights at a frequency higher than 60/50 Hz (frequency of household line power AC in USA/everywhere else, respectively), but that would require delivering power at that frequency -by reworking all the generators and frequency-dependent devices.
Re:LED are as effcient as Incandesent (Score:2)
Buy a "high-frequency", "bright-white" fluorescent bulb.
I find normal long-tube fluorescents *extremely* annoying, but the compact fluorescents I use in my house (which described themselves as above) do not bother me.
I presume they use some sort of frequency-doubling-like technique to go from 60hz line to 120hz (or more) effective frequency, but whatever they use, they finally "got it right". I highly reccommend them.
As the *only* remaining down side, they take a second to come on (literally around one second). If you expect the instant-on behavior of an incandescent, this will take some time to get used to. But considering that I've cut my electric bill by almost a third, I can deal with the difference.
Laws of physics (Score:2, Informative)
Re:Laws of physics (Score:2)
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?
Re:Laws of physics (Score:2)
Re:Laws of physics (Score:2)
Physics of LEDs (Score:3, Informative)
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."
Re:Physics of LEDs (Score:3, Funny)
No doubt someone will be along to mod you down any moment.
Re:Laws of physics (Score:1)
Energy is conserved. What do you think it would be converted to?
Ah, ... conservatism?
Re:Laws of physics (Score:3, Informative)
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).
Re:LED are as effcient as Incandesent (Score:1)
All you need to do to get efficiency out of them is hook 'em up to a little inverter - supplying brief pulses of current with a very low duty cycle at about 10 kHz or so - the light will seem perfectly bright and usable, as the response time for even a white LED to go from off to 100% is nothing compared to the time it takes a human retina to notice that the light is already off.
Obviously, this is going to save power - the average power usage would be tiny, the intensity of a pulse would not.
You just can't do that with a incandescent bulb.
The better LED torches already do this - they practically SIP current from a battery, and a penlight sized torch using a single white LED is enough to read by in an otherwise unlit room - left in one place pointing at the ceiling!
Plus it lets you get away with another neat trick too - running the LED at a higher peak current then it is rated for, so long as the pulses from the inverter are suitably short, and the average power doesn't exceed the LED's power dissipation rating, you can get even more brightness.
With a suitable driving circuit, i don't see why LED's can't be used instead of other light sources for most things, as when run pulsed in this fashion they are extremely efficient.
(The only potential downside is the faint whine the coil in the inverter makes - but this could be removed given careful enough construction.)
A couple of places to check out... (Score:5, Informative)
LED brass desk lamp [photonlamp.com]
Several models to choose from [optiled.biz]
DC Voltage (Score:4, Informative)
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.
Re:DC Voltage (Score:2, Flamebait)
The circut looks like the following excuse the asci art (which would have been bellow if slashdot was worth a crud). You can also use capacitors and zener diodes to smooth out the ripple that is left in the wave giving a truer dc ouput voltage.
Re:DC Voltage (Score:2)
Re:DC Voltage (Score:2)
Re:DC Voltage (Score:2)
Connect the diode in parallel with the LED, cathode to anode, so that it clamps the reverse voltage across the LED to one diode drop. Then, all you need is the dropping resistor for 120 Vac operation.
Do the math tiger (Score:1)
dansdata letters (Score:5, Interesting)
But he says it better than I could.
Not as efficient as some claim (Score:4, Informative)
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 (Score:5, Informative)
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.
Any recommendations? (Score:2)
Have you had this problem, and regardless of that answer, do you have any recommendations for flourescent torch lamps or wide area lamps?
Re:Any recommendations? (Score:2)
Re:Any recommendations? (Score:2)
Re:Any recommendations? (Score:2)
Yep! When I first started buying CF bulbs, they just didn't seem to produce as much light as their claimed equivalent bulbs. So now I use the next size up for everything. This makes the room brighter than before, and I'm still saving plenty of power.
Re:LED only good for low power apps (Score:1)
I'd be very interested in outfitting my house in total LED, saving power form incandescent, and staying away from those horrible flourescent.
~Donald
Wrong mental model (Score:2)
Re:Wrong mental model (Score:1)
Migraine sufferers are even more sensitive to annoying high-pitched noises, which many of the less-than-perfect high-frequency ballasts emit. Plus I want to harm whoever decided to install those bastardly things in my student lounge. As the (volunteer) audio tech there they bring me nothing but pain, inducing their signal into everything. Balanced cables don't help, as it seems to permeate the equipment itself. ARGH!
another place... (Score:4, Informative)
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.
Comment removed (Score:3, Interesting)
Re:not really what you want, but.. (Score:4, Interesting)
http://www.ebtx.com/mech/optolite.html [ebtx.com]
They sound like the real deal. I'm going to stop by target and grab one.
Re:not really what you want, but.. (Score:1)
Unlike the 3-LED version, this uses expensive watch batteries.
Pretty durable, lasted about 2 years until the "reflector" cover came unscrewed and the exposed LED fell out a short time later. One nice touch was that the manufactuer put a spare rubber button in the rear battery cover, in case the original wore out or was lost.
Bah, piddly little light. (Score:2)
If you want BRIGHT LED flashlights, look around on http://www.candlepowerforums.com/ - The creations of forum users ElektroLumens, Lambda, McGizmo, dat2zip, and Mr. Bulk are simply incredible. dat2zip sells an excellent drop-in for MiniMags that includes a DC/DC converter circuit and a 1 watt Luxeon LED. (Equivalent to 10-20 of Nichia's best 5mm units.)
small applications (Score:2, Interesting)
Re:small applications (Score:4, Informative)
Re:small applications (Score:1)
I cannot imagine that the
Indeed...perhaps the reason they do not put LEDs for the yellow lights is that in the next few years they plan to get rid of them all together...
(ok....I know that was offtopic...but that subject is just my pet peeve....so sue me.)
Re:small applications (Score:1)
Re:small applications (Score:2)
I've lived in states where the lights have long yellows, and I've lived in states where they have short yellows. Drivers quickly adjust for the length of the lights.
With a longer light, you simply discount the first couple of seconds and ignore it before you start your internal timeout. The same selfish people are going to be running the red light in either situation.
I've seen no fewer red light runners where the yellows are longer than where they are short.
Re:small applications (Score:2)
Reaction time is better. It's supposed to be 200ms better, and you can see the difference.
Re:small applications (Score:1)
Re:small applications (Score:2)
Re:small applications (Score:1)
How about lightly sanding the LED. The roughed up surface should spread the light better. Maybe you'd end up losing too much light.
If you don't mind wasting/replacing an LED or two it might be worth a try anyway.
Re:small applications (Score:1)
Maybe it's just me, but I find the new LED traffic lights cause a night-myopia-like effect in me. If I see one of those at night, a large area surrounding the bulb will be strongly overshadowed by green. Which sucks.
Perhaps it's just an intensity issue. I don't think it's my eyes, as my opthamologist thinks they're just fine.
Re:small applications (Score:1)
They didn't? Maybe I should quote what was said (emphasis mine):
I replaced all the bulbs with blue LED's, and they look great. Kind of expensive, but they'll last forever.
Being that blue LEDs have just gotten "cheap" in the past few years, I would expect that they are probably on the bottom of the barrel for lifetime right now. A '67 volvo (the vehicle in discussion), had it been equipped with blue LEDs when built (which, of course, didn't exist at that point) would have no dash lights whatsoever today.
I guess you're right. He didn't say indefinitely, specifically. He said forever. Which would be a synonym.
LEDs are cool, fiber-optic is cooler (Score:5, Interesting)
Frankly I look forward to having one or two "light boxes" in my attic keeping much of the heat out of my living space (or in the winter pulling it into the HVAC system), only having to replace a few well engineered super-efficient bulbs in a handy box every few years, plugging in a fiber cord instead of a an electrical one for a lamp. LEDs might become a good retrofit for older wired-not-fibered places but for new construction I'm looking to plastic.
Re:LEDs are cool, fiber-optic is cooler (Score:1)
Re:LEDs are cool, fiber-optic is cooler (Score:2)
Wouldn't that fiber setup waste a lot of energy when you only want one or two lights on in the house--say when you've got your nightstand light on to read?
Turning on a powerful central light source seems like an awfully big waste at low utilization. I wonder how designers would get around this.
Are there any websites that explain a fiber-based central lighting system?
-AP
Color Kinetics (Score:4, Informative)
As for prices, I'm sure if you have to ask, you can't afford it...their 4 color intelligent nightlight [cksauce.com] looks relatively cool for $8.
LEDs: White Not There Yet (Score:1)
First, as others have noted they are not as efficient as compact fluorescents. Remember that they need low voltage DC so you have transformer losses to factor in.
Second, the less expensive ones are very, very "blue" in their output and have big dips in the output spectrum. The light is very "harsh".
Some co-workers follow LED technology for professional reasons (think of a place where spare light bulbs can only be brought up every 3-6 months at $10k/pound transport costs), and passed me some papers that project that they will probably be ready for home use by 2010, and industrial use somewhat before that. They already are starting to dominate in areas where the cost of replacement is high, or where a burn out is a safety hazard.
DC need not be uncommon. (Score:1)
Compact Fluorescent (Score:5, Interesting)
You get roughly a 4:1 amount of light per watt in a compact fluorescent as compared to a conventional incandescent bulb.
I recently went through my parents house replacing bulbs. I used mostly ~15 watt bulbs (60 watt equivilant) and in a couple of areas where really bright light was needed I used 27 watt bulbs (~100W equiv.)
There were two fixtures in the hall that used a total of 600W of light originally and now use a total of 60W using compact fluorescent bulbs. The hall is still quite bright, but now use four 15 watt bulbs as opposed to eight 75 watt bulbs.
It doesn't take a math genius to see that these bulbs pay for themselves relatively quickly via savings in the electric bill. Not only that, but they last a long time. I've been using them for about six years and I've had only *one* bulb die in that timespan (that was a Philips if anyone wants to know).
Home Depot is selling them pretty cheaply right now. There is no excuse to not buy a pack and try them out. You are totally justified in spending the money for the bulbs up front and put them in now, knowing that if you annualize your costs you are actually saving money.
These bulbs cannot be used in dimmer type sockets, and other than the really small 9 watt models some of them have a hard time in very small enclosed fixtures.
You will realize the most immediate savings if you replace bulbs that are in use for extended periods, like driveway lights or hallway lights.
Re:Compact Fluorescent (Score:2)
Perhaps more modern fixtures are made with these bulbs in mind, but certainly older ones are not. For these bulbs to really work, we need to start seeing lighting fixtures that are designed specifically for their dimensions. Or better flourescent lamps. If I owned my place I might consider building recessed flourescent lighting (incidentally, Frank Lloyd Wright really liked flourescent lights used this way).
Re:Compact Fluorescent (Score:1)
The very cheapest ones that they sell at Home Depot today have only been around for about a year or two. They start right up without flickering, have a smaller ballast, they are relatively CHEAP ($7 for a three pack of bulbs on a sale day today, vs. $22 I paid for an individual bulb 6 years ago).
The 9 watt bulbs are probably smaller than your average 60 watt incandescent in external dimensions.
CF's fit great into lamps now. They also fit great into driveway lights, courtesy lights by the front door, etc. They also work very well in cieling fans.
As for brightness, I have a desk lamp that is rated for no more than a 45 watt bulb (incandescent) that now has a 27 watt CF bulb which is the functional equiv of a 100W incandescent. Very bright! Earlier on I was so smitten with the savings of CF bulbs that I was putting 27 watt bulbs everywhere. But now I use mostly ~15W bulbs because they are still plenty bright (just as bright as the bulbs they replace, usually) and because right now they are the cheapest. In more decorative fixtures that use multiple bulbs, or where space is tight (like you mention) I've been using the super compact 9W bulbs with great success. The 9W bulbs are a bit dim for general room lighting but most of the time that I use these, there are 3 to 5 bulbs in the single fixture anyway.
That said, you concerns have already been largely addressed by the industry. Get thee to Home Depot and try out the latest & greatest designs.
Re:Compact Fluorescent (Score:2)
Here in southern california, the cost of the bulbs is subsidized by the utility companies. The nice 27 watt ones are about 3$.
But watch out for what you buy (Score:2)
Re:Compact Fluorescent (Score:2)
What I'd like to see is a 3-way CF bulb that's reasonable in size. They're too tall for most lamps.
Be careful of mercury content of these bulbs (Score:1)
Kris
exaggeration (Score:1)
Your average compact fluorescent has far less mercury than your average fluorescent.
So for God's sake, please stop taking your temperature before you die!
Re:Compact Fluorescent (Score:1)
Re:Compact Fluorescent (Score:2)
Re:Compact Fluorescent (Score:1)
The fridge would probably be the very last place I put a CF, just because it is going to yield the least benefit (this is a light that is only ever on a few seconds at a time).
I think it is best to start with lights that are on the longest, and work your way down from there.
Re:Compact Fluorescent (Score:2)
Re:Compact Fluorescent (Score:1)
I bought an LED bulb 2 years ago. (Score:2, Informative)
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.
Re:I bought an LED bulb 2 years ago. (Score:2)
Correction: It was late 2001. This was my part of the President's "Go out and buy stuff to save the economy" plan.
LEDs are great for certian applications... (Score:2)
It would take quite a number of LEDs to match even a dim light bulb.
The reason LEDs are considered so efficient is that their light output is based on the current through, rather than the voltage through them.
Inefficiencies are introduced in the circuit used to power the LEDs. In most small circuits one would use a simple resister to limit the current. This resister typically wastes 2-3 times the energy that the LED itself consumes. This isn't an issue since one LED and resister should consume less than one tenth of a watt.
Cheap LED light bulbs for home use might use a simple resister scheme. If so, they will consume nearly as much energy as an equivilant incandescent bulb, and let off as much heat.
A truly efficient LED light bulb will have several high-output LEDs, and a small, 90%+ efficient switching current regulator. Such a bulb should still be more efficient than current lights. This can be shown by how little energy is given off by other (non visible light) forms of radiation, such as infrared light and heat.
-Adam
Re:LEDs are great for certian applications... (Score:2)
Why don't they build just one giant LED instead of creating arrays of 10 or so LEDs?
They do (Score:3, Interesting)
Currently the largest LED is Luxeon's 5 watt emitter, which gives off around 100-120 lumens. No one has been able to manufacture anything larger easily yet. There's a rumored 10W LED coming from another company, although its light output is specced as LESS than Lumileds' Luxeons (i.e. it's less than half as efficient.)
5W units are $40/each in small quantities, dropping to $24 or so each in larger quantities (100+) They are VERY hard to obtain.
I built them myself and they are great. (Score:4, Informative)
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
Cheap...christmas lights & molding (Score:2)
On sale, a string of 100 went for $6 USD at WalMart in January. Now...probably $20.
Paint those walls with light (Score:3, Interesting)
Using them in the venue I work in and they really do look great!
YMMV on whether they're appropriate for your home application though! I would suggest, however, if you are going down the hardcore-lots-of-new-fixtures-everywhere route that you consider using fixtures that talk DMX [usitt.org], which'll make life a darn sight easier when you want your rooms to slowly change colour over the day!
Not LED's, but we like our Microsuns (Score:4, Informative)
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."
What about the Health Effects of lighting systems? (Score:1)
On a recent science or medical info radio program,
it was said that:
- rates of breast cancer in women may be linked
to the amount of time they work in artificial
lighting (eg office flouro's)
The research found that women who work at night,
presumably in artificial lighting, have higher
rates of breast cancer.
Blind women have much lower rates of breast
cancer.
'don't know if it matter -which- type of
lighting they're experiencing, but it might
be good to know... ie -before- choosing
a lighting system technology for the home.
I don't have a link to the original Danish
research work, but here's a German link:
www.labournet.de/diskussion/arbeitsalltag/gh/br
Other links are available; cf:
Google("breast cancer" artificial lighting blind rates)
Re:What about the Health Effects of lighting syste (Score:2)
cancer.
Could it be because they're not pumping gas and otherwise exposing themselves to chemicals like sighted women are?
I wouldn't be surprised... (Score:2)
White LEDs are similar, except that they use blue light (much safer) to charge up the phosphor.
Check out the Luxeon Star (Score:1)
More on Luxeons (Score:4, Informative)
Very little in the terms of line-powered lights, but people are starting to experiment (very carefully...) in that area.
one more time. (Score:2)
I.e. they aren't the best choice for light today,
however they have been improving at close to what Moore's law predicts,
so perhaps in 10 years, they will be the ultimate light source.
Today however, they are still too expensive (90 dollars vs 90 cents for a standard bulb) and only a little more efficent.
Last year the light/power breakdown was something like this:
Lumens/Watt Light Source
100-190 low pressure Sodium (HID)
50-150 High pressure Sodium (HID)
60-140 Metal Halides (HID)
20-60 mercury vapor (HID)
85-95 32 watt T8 fluorescent
60-65 standard F40T12 cool white fluorescent
48-60 compact fluorescents
45-55 Super bright Red/Orange LED
35-45 Super bright Green LED
20 T3 tubular halogen
15-25 bright white LED
5-25 Halogen
17 standard 100 watt incandescent
6 incandescent night light bulb (7w)
<6w incandescent flashlight bulbs
The best choice for the home today is almost certainly the cool white tube fluorescent, with an all electronic balast.
They don't "whine" or flicker like the older fluorescent lights,
the tubes cost about $2.00 US, they are near the top in efficiency, and the last for years.
The down side is that they require special fixtures, and they flicker more than incandencances, which is a problem for some people.
Compact flourescents are the next best choice,
but they don't have "instant on" which can be annoying for some rooms.
In my kitchen, I have an old 3 socket fixture.
I use two compact flourecents and a long life incandescent and it works well.
Yes, this is the third time I've made essentially the same post, what's your point?