X-No-Archive: Yes
I'll consider LEDs when all of these are met:
LED's don't have to be the best lights available in order to
be adopted, but they do need some features which they can do
better than other light sources, and they don't yet have enough
such features, which is why they are currently only a minority
curiosity in lighting. They are currently running from behind
in features, and it remains to be seen if they can catch up with
existing lighting technologies, or if something new will appear
and overtake them before they get off the ground.
Just like the two men faced with a hungry lion; to live they don't
have to be able to outrun the lion, they just have to be able to
outrun the other man.
one unit can produce ~2600 lumens
That's ridiculous -- there are plenty of lamps in use with much
lower outputs than that. In my house, I have one at 180 lumens,
and a few at 350 lumens. Actually, I have only one light in the
whole house which is as much as 2600 lumens.
Colour temperature of 2700K before I'd use them in the home so
they blend with other lighting and are the right colour for home
lighting levels. Probably 3500K for use in an office. All the
ones I've seen so far are much too high colour temperature for
general purpose lighting.
95% lumen maintenance at 40% the rated life
one 2,600 lumen unit doesn't cost more than $5 for 20,000 hours of
useful time (so, if it can last 40,000 hours and maintains 95% after
16,000 hours, then it's acceptable to me if it costs $10 each)
That's just as silly as your first assertion.
A 350 lumen compact fluorescent retrofit is about $4 in the UK
for ~8000 hours. An LED retrofit would need to be similarly priced
if people are going to buy it. (Selling at twice the price based on
twice the lamp life would probably significantly reduce the market.)
A 2,600 lumen lamp is probably not what any designer should start
considering for LED technology -- they are just way off on all fronts.
efficacy of lamp driver+lamp unit must be greater than or equal to 85
lumens per watt.
In terms of efficiency, they don't need to be that high to be viable.
20 lumens/watt would get them into the market. However, they need to
solve the heat destruction problem -- one way is to become much more
efficient, but there may be other solutions. If you can make a 20W
equivalent light output MR16 which doesn't cook the LEDs, that would
be a good start. I think technology only manages around 5W currently.
Other features of LEDs which might make them viable today in some
applications would be any that require the common red/yellow/green
colours with narrow beam and a tiny light source -- for this LEDs
are pretty impossible to beat at low lumen levels already.