On Fri, 28 Aug 2009 09:31:47 +0000 (UTC),
(Andrew Gabriel) wrote:

By Sep 2012 new technology LED lamps should be in full production

that's just 3 years but I'd like your optimism to be true!

It's a promise the LED lighting industry has broken for every
one of the last 20 years!

We now have some very viable units in mass production at reasonable
prices. I understand your scepticism, but I do not see 3 years as
being overly optimistic. Right now it would be quite possible to
illuminate your entire house (including garden floodlights) with
commercially available LED lighting.

Personally I would fit about 20 or so small flush-fitting 5W LED units
into the ceiling of a medium size room. It would provide an
*extremely* bright but glare-free room (when needed) and an even,
shadow-free light. Dimming can be achieved by not having them all
switched on, which also has the advantage of allowing part of the room
to be bright (perhaps for reading) and another part dim (for TV
viewing).

There are some reasonably efficient LEDs in the lab, and
available at really stupid prices.

No, efficient LEDs that are bright and efficient have been in
commercial production for a couple of years now, and the prices have
fallen to economically viable levels (still relatively expensive but
dropping fast).

There really is nothing technologically on the horizon which
allows you to make a 100W [equivalent] retrofit GLS LED lamp
though.

It will be necessary to replace the light fittings for the foreseeable
future, yes. Not a huge undertaking, but not trivial either. The
more directional quality means that light placement is more critical,
and as said, plan on using a spread of several units to replace a
single tungston/CFL unit. I would recommend that anyone planning to
redecorate a room should look into fitting LED lighting as part of the
redecoration. I can almost guarantee that you will be pleased with
the result.

Widespread LED lighting will require new purpose-
designed luminares to solve the thermal design issues which
come with LEDs.

Yup - but don't use future tense. It's already been done and is
available to you right now. Unfortunately there are some really crap
designs and also unrealistic claims together with the good stuff, and
buying a badly designed product is likely to make a person dismiss the
technology as being inadequate. Price is not necessarily a good
guide.

Commercially, metal halide lamps have already filled this space,
and you may see these moving into domestic use as the chinese
bring the costs down in bulk.

Metal halide are not as efficient or long-lasting as LED. And whilst
metal halide is a mature technology where incremental improvements are
relatively small and infrequent, LEDs will improve in both quality and
price quite rapidly as the market grows.

--
Cynic