I've got a problem. I happen to carry the distinction of being the one
>responsible for changing lights. Much as that's a problem in itself, the
>biggest problem is.....the front porch light (surprisingly, it's not a
>stairway light, eh?), which happens to be a hanging, upside-down, enclosed
>fixture. And they put two screws in the thing, so it's almost impossible
>for a single person to replace the bulb thus inserted. Really quite
>remarkable how no one thought of this.
>
>Besides modifying it, which I may consider because it's just that bad, in
>the mean time I need something that'll last. We've already tried the "ten
>gajillion hour" CFLs, which died in all of, you know it, three months. I'm
>guessing something high voltage (130V+?) and incandescent. Any
>recommendations?
>
>Tim
They are still expensive as heck, but you can get LED lamps. Perhaps below US$50 each for 100W equivalent, but always over 30,000 power on hours life and some (more expensive) are rated at over 100,000 hours power on.
Buyer beware for life expectancy of LED "lightbulbs" and the like, especially if they are white ones.
100,000 hours is a widely-repeated number, to the point of "conventional wisdom".
White LEDs often fade significantly well before then - I dare to say they mostly do. Colored LEDs, on the other hand, appear to me to have most operated for 100,000 hours or more to be keeping on trucking rather well after working for so long.
It appears to me that better heatsinkable white LEDs take 50,000 hours to fade by 30% at "characterizing current" ("typical current") when heatsunk to what I call a "moderately conservative extent". Much longer life expectancy as in 100,00-plus hours appears to me reasonable if they are both significantly underpowered and heatsunk to extent to keep the junction temperature well below the "old traditional" maximum recommended LED junction operating temperature of 85 C. In general, LEDs are more efficient when cooler and most blue, white, and non-yellowish-green ones are more efficient when moderately or moderately severely underpowered - even regardless of temperature.
A main difference between white LEDs and most colored ones is that white LEDs normally have a phosphor and over 99.9% of colored ones I have seen don't. The few colored LEDs that I have seen with phosphor are pastels, pink, lavendar/"purple" (as opposed to "violet", which is nearly-UV or an indigo-bluish-violet color with some "blacklight" effects), or a non-amberish maybe-slightly-chartreusish yellow close to 255-255-0 on a usual monitor. Also beware - violet and UV LEDs with epoxy bodies tend to age fast due to UV or nearly-UV being hard on the epoxy.
I have seen sone reasonably credible numbers for even better 5 mm / T1-3/4 LEDs to fade significantly (don't know whether by 30% or 50%) in as little as 6,000 to 10,000 hours. I don't know whether this is at "characterizing current" of 20 mA or at maximum current of 30 mA. Some of this is news years old and some I got more recently.
One model of a white LED nightlight that I tried had "half-life" close to half a year. I would prefer green or blue LED nightlights over white ones for better life expectancy as well as having a spectrum more favorable for stimulating "scotopic vision" ("night vision").
Most of your sloppily called "colored" LEDs are standard monochromatic LEDs. They are cheaper to manufacture that way.
White LEDs are for most purposes are a variation of fluorescent lamps. (no Mercury content though)
One of the best reliability engineers i ever met liked things "nicely derated". 3 W white LED, run it at 1W, you will like the life improvement. Now, of course, time cost of money and time cost of devices will interfere with this.
They actually do that. It gives a wierd color rendering effect - with red objects coming out "day-glo" bright and wood tones coming up very reddish/pinkish. Oak has a color like that of mahogany. Skin tones come up reddish.
The DLP tv I have uses red, blue, and green LED's instead of a lamp and color wheel.. white screen is nice and white.. but I don't know how that would translate to a lighting application..
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