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?
LED light bulbs
LED brass desk lamp
Several models to choose from
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.
Dan covers this in one of his more recent letters sections. He states that compared to Halogen bulbs, LEDs aren't as efficient, and are best suited to accent lights.
But he says it better than I could.
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.
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"You are not remembered for doing what is expected of you." - Atul Chitnis
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.
I don't read ACs: If a post isn't worth so much as a nom de plume to its author then I wont bother either.
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.
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.
"Nature doesn't care how smart you are. You can still be wrong." - Richard Feynman
I can't believe I haven't seen it mentioned here yet (maybe I am browsing at too high a threshhold), but compact fluorescent lights are the current way to get the best bang for your buck in home lighting.
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.
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