DaveS;

LEDs are about 2 years from becomoing affordable, but until then you can equip a home with CFLs  with a low investment

I only have 2 incandescents in my home , 3 LEDs , most are CFLs or tubes

Fluorescent lights give my wife seizures.

This may sound like a dumb question, but if LEDs are the future of lighting, will there be a major switch in the type of fixture or bulb socket, or will they simply make LEDs fit into the existing types?

Jelly,

The LEDs that I have seen at trade shows fit into regular sockets.  I think LEDs will fill a niche market until OLEDs are available.

The LEDs I have a regular base, the nice thing about them is they are dimmable.  I have tried some CFLs that are dimmable, but they do not work well. The CFL flood lights are OK once they get warmed up

The answer is both. They are making more an more types matching existing types - but I have also seen some very cool new ones as well. Since they have such a long lifespan you are seeing some models integrated into the fixtures as well.

I was talking with a friend about building with a 12 v led as major ambient lighting in a new house using solar as primary source. He was saying that led 12v or 110v systems are not viable because you need larger wiring for the long runs. I was surprised especially with the 12v. I'm not an electrician so I don't know. Anybody ??

Posted By laclu on 16 May 2010 11:17 PM
I was talking with a friend about building with a 12 v led as major ambient lighting in a new house using solar as primary source. He was saying that led 12v or 110v systems are not viable because you need larger wiring for the long runs. I was surprised especially with the 12v. I'm not an electrician so I don't know. Anybody ??

110-120V is fine for distributing power to LES, but delivering power at 12V requires very fat wires:

  watts=current x voltage

Delivering the power to a 12watt LED takes one ampere at 12V, but only a tenth of an ampere at 120V.  The more current your running in a wire, the fatter it has to be in order to not heat up from it's inherent resistance.  You can run 10 LED fixtures at 120V with the same size wire that it would take to run just 1 at 12V.

LEDs are inherently low voltage- there is a conversion loss going from either 120V or 12V down to LED's operational voltages, but the percentage of the power lost in that conversion isn't dramatically different for either.  (The actual operational voltage is not  constant with LEDs, but varies with temperature.  Constant luminosity is achieved within the fixture's control circuits by keeping the LED's current, not it's voltage fairly constant.  (LEDs can be fairly well-approximated in electronic models as a diode in series with a resistor, with temperature coefficients applied to both the diode & resistor.)

have you checked at home depot? I usually buy my home lighting needs there. But you can also checked it online. There are several stores  where you can order LED lighting.

Posted By arisyap@gmail.com on 23 Jul 2010 05:13 AM
have you checked at home depot? I usually buy my home lighting needs there. But you can also checked it online. I think there are several stores  where you can order LED lighting.

yes Home Depot as well as Sam's Club stock's LED bulbs, Sam's is better priced but neither is yet affordable for mainsteam use

If you have an application that needs long life, consider CCFLs at ~25K hours. I only consider LEDs at 3w and less.

Be careful of LED specs - at max lumens, the life and efficiency aren't very good. Ie, you can have a reasonable amount of light or efficiency and life - but not both.

If efficiency is the main concern - use T5 or Super T8 fluorescents.

I have heard that there will be some major LED shortages in the near future as the demand for LED-intensive products (primarily TVs) continues to skyrocket. I wonder if this will affect their use as a residential light source?

jonr;

3 years ago I outfitted my entire home interior and exterior with flourecent lighting, after all the years it has been on the market,  the performance is still poor, life cycle is poor, dimmable candelabera bulbs do not work well, flood lights come on dim and take a long time to get to full illumination. Dissapionted that I saw no difference in the utility bill?
I have 68 bulbs/tubes with about a $400. investment I amnot  noticing  a return and the longevity is not as advertised. I am hopping that LEDs are soon affordable

This might be worth reading:

http://www.betterbulb.com/

Thanks Jonr.  I had not heard about CCFLs.

Posted By Alton on 24 Jul 2010 09:48 PM
Thanks Jonr.  I had not heard about CCFLs.

Self-ballasted cold cathodes bulbs have been around quite awhile, but the higher power versions are typically a bit behind the efficiency of "standard" T4 or T2 CFLs.  They tend to outlast CFLs by 2-4x, but have most of the standard drawbacks of CFLs such as dim turn-on, particularly in outdoor colder weather applications. Where they really beat CFLs is in low-wattage low-luminosity or "mood lighting", where a 2-3W CCFL delivers more than enough light to avoid tripping on stairs, or small table lighting, and a few 5 watters is can deliver pleasant levels of low glare dining light, etc.  Without filament currents to manage, CCFL ballasts are simpler beasts than CFL ballasts, and dimming them is typically easier (but very low quality compared to a fluorescent fixture with an electronic dimmable ballast.)

They're also good for flashing display-lighting, since unlike standard CFLs turn on is always "instant on" (if dim, when very cold) and the electrodes are not much degraded with successive turn-on cycles, and will outlast CFL & incandescent technology in those apps.

In my own home I have something like a dozen 2W-5W CCFLs installed, at least half of which see daily use.  When LEDs hit 2x the efficiency for similar color temperature (& similar or better color rendering index) I may start swapping them out.  I may not live long enough to just wait for them to burn out.  The only failures I've seen with them were within the first weeks of operation, presumably from manufacturing defects, since the replacement bulbs out of the same case have gone 3+ years.  (The manufacturer of those early-failures was TCP, if it matters to you.)

I (and others) don't see "dim turn on" with some or most CCFLs, even in cold weather.

Posted By jonr on 29 Jul 2010 08:14 AM
I (and others) don't see "dim turn on" with some or most CCFLs, even in cold weather.

Really?  Do you have any manufacturers or model numbers to recommend for outdoor cold-weather use?

The TCP & Cool-Lite CCFLs I've used outdoors have all had a noticeable minutes-long ramp to full luminosity when it's freezing outside.  With a lux meter it's still measurable in indoor apps too, but it's not particularly an issue to the naked eye (even though it's noticeable if you're really looking for it.) 

The ramp is largely a function of the vapor pressure of the mercury inside the tube- the warmer the mercury is the lower resistance/higher arc current  is until the ballast limits peak arc current.  Old-school magnetic-transformer linear T4 & T5 cold custom-tube cold cathode has the same issue, which is why it is primarily used in indoor applications.  A primary selling point of the magnetic transformer cold-cathode approach 25 years ago was better dimming capability than filamented argon-mercury fluorescent technology .   But as the power electronics for higher frequency ballasts got better & cheaper through the 1990s standard-stick dimmable T8s surpassed cold-cathode quality in several respects, not the least of which was the absence of perceptible flicker at low light levels.  I haven't looked at larger cold cathode since ~1995 though- don't know who (if anybody) is chasing higher frequency dimmable ballasting for those.  They are conceptually simpler, but the voltages much higher than standard linear fluorescents.

The electronically ballasted tiny cold cathode used in scanners & flat-screen video backlighting apps for the past coupla decades are pretty steady, with a very short ramp to full-on, but the ballasts that control them don't fit in an Edison screw base for a bulb.  They are rapidly being supplanted by more rugged & efficient LED technology in some products.

Mine aren't easily accessible, but they may well be a constant or boosted current design.

It will be interesting to see what developments are coming for more residential applications of LED lights. LED lighting technology has been researched and developed for the past two decades and we are beginning to see practical applications from this work.