In article ,
Tim Mitchell writes:

Yes, LEDs are definitely on the up. They are not as energy efficient as
the manufacturers would have you believe though.

They are about the same energy efficiency as a 12V halogen
(maybe nearly twice that of a mains halogen). So the 1.8W
one mentioned (assuming that all goes into the LED's) will
be about the same light output as 3W worth of mains halogen.

LED's are very directional. The area of the spot is probably
less than 1/100th of that of a mains halogen, so if you consider
only the intensity on-beam when comparing light output, you
will be out by something over 2 orders of magnitude.

--
Andrew Gabriel