LEDs - My experience
I have begun to switch to LEDs wherever possible. There are, however, several problems I have encountered (aside from cost, which is amazing).
1. Many are just not bright enough. It takes careful reading of the specs- pay attention to the lumen rating, not the "watt equivalent" rating- to get what you need for adequate lighting. The smaller ones can be useful for small lights and for spot lighting of pictures, as well as night-lights.
2. The color spectrum (as described in previous posts) is narrow, producing an effect similar to that of street lights (mercury, particularly) in which there appears to be enough light, but it just doesn't look right. The "warm white" is achieved in some by placing an amber filter over the source; not very efficient. I have seen, on a cruise ship, large arrays of red, green, blue and white LEDs (apparently 1-watt) which produced a satisfactory wide-spectrum illumination. I have not found these commercially available. I am hoping that someone will market a similar product contained in a single "bulb."
3. Many of my lights are controlled by dimmers, mostly X-10-controlled, which work well with incandencents, poorly with fluorescents, and badly with many LEDs. The LED problem is that, when the dimmer is at it's "off" setting, the bulbs nonetheless flicker at ~1 per 1-2 second flashes; this combination of those LED bulbs and the dimmers is therefore unusable.
4. Continuing the "dimmer" theme; in order to have some control of lighting intensity (useful for various purposes, e.g. bathroom lights which come on dim when one gets up at 0200, but bright when needed at other times) it appears that I will have to add an additional circuit to each fixture, and install one bright light and one dim one, with "1-2-both" controlling switch. I may be able to work around this by installing two X-10 on-off controls at the fixture, and use an X-10 wall controller with the necessary settings, avoiding having to run an additional set of wires through the wall and ceiling. I expect such setups may be eventually marketed, but are not presently available for the end-user. (If I have to run additional wiring, I will replace the fixtures and bulbs with a 12-volt setup; the "I^2 R" loss is not as significant at the low current of LEDs as it is with incandencents.)
5. Outside floodlights, and 12-v decorator-landscape lights are very suitable for being replaced by LEDs. I use these in several areas. I also use 110V LED amber bulbs for decorative outside lighting on entrance posts, etc. I use 12V LED lights for illuminating steps. These are durable, efficient and effective.
6. I am sensitive to flicker; even 50-cycle incandencents have, to me, noticeable flicker. I notice, but have learned to not be bothered by, the "rainbow" effect of my HD LCD projector. BUT I have not had any noticable flicker from my LED bulbs. I suspect that this is due to the power system incorporated into the base of the bulbs; presumably it has a capacitor on the DC output which avoids this problem. I recommend a DC-DC regulator be used for auto tail-lights; I agree the flicker is annoying.
7. LED flashlights are, for me, standard. I have modified all my flashlights to use LEDs. The battery life offsets the cost. The bulb life is an extra bonus.
If I were to design my house lighting "from scratch" at this time, I would wire it up for 12VDC LED lighting; retrofitting, however, is a more difficult issue.
I expect the availability of LED lighting to increase rapidly, as fuel/electricity costs continue to rise.
I look forward to a time when my solar electric equipment (currently supplying an average of 17 KWH/day) will totally supply my electric needs, facilitated by efficient refrigeration, LED lights, and lower power-demand audio-visual-electronic-computer technology.
