I genuinely think it will be literally 10+ years before LEDs could be considered to be proper replacements in all aspects of: light output, luminous efficiency and reliability despite what I keep being told by supposedly educated people. What looks good on paper or in computer calculations does not translate into real life situations.

The LED concept is a good one, we just need to stop the Chinese from making all of them, can you imagine if a UK factory opened, concentrating on LED, but with the dedication, reaserch and commitment that the likes of Thorn and GEC had in the 70s and 80s!

I agree Rich, and believe that LED is indeed the future of lighting until the next big thing, even though I find it unexciting. The only place I would consider using LED at this present and relatively immature stage of its development would be in general household lighting. All high power LED installations (including street lighting) I have seen have a high failure rate, are very glary to the eye and more often than not produce far less lumens than the light source that they replaced.

I suspect older technologies were just as unreliable at their early stages. Id say we are with leds, as we were with fluorescent tubes in 1945, rated for 3000 hours at best, or even incandescent lamps when they were still carbon, fragile and short lived.

I agree to some extent Jonathan but LED is not at an early stage any longer, it has been pushed as the 'best thing since sliced bread' for some years now despite its proven lack of reliability. Even when fluorescent lights were being introduced in the 1940s they were such a massive improvement from the lamps they were replacing. 3000 hours was still 3 times the lifespan of a much more inefficient incandescent. LED replacements on the whole today are dimmer and less reliable than what they are replacing. It is a sorry state of affairs and I look forward to the day when LED could truly be considered a proper replacement for discharge lighting in terms of equivalent lumen output for far less system watts, genuinely longer lifespan and just as cheap to purchase. Like I say, this scenario is going to be many years away. Long live fluorescent and discharge!

If you want my opinion, I think LEDs will be obsolete before they get decent, and they will be confined to history forever. I believe the next technology will be although based on LED's fundamentally, but instead, the dies are grown on a sheet of plastic, laminated into a window pane, and the windows of buildings will themselves, become the light sources. They will of course HAVE to be reliable a that point because a window cant be easily replaced. Which brings me to another issue, LEDs are made with the cheapest shit. and will continue to be until they are used in a more 'structurally integrated' way like hence and are required to be reliable.

You're talking about Organic LEDs (OLED).

Yep