Pat Kiewicz wrote:
-- pelirojaroja said:

On a lumens per watt basis, metal halides win over flourescents.

No, generally they don't. Triphospor T8 fluorescents with electronic
ballasts can exceed that magic 100 w/l ratio. There are a *few* MH lamps
that start out just as efficient (but not more efficient) but MH lamps lose
their brightness fairly rapidly, while triphosphor flourescents maintain
about 90% of their original brightness throughout their 20000+ hour life.

That's why I'm
seeing them more and more often in commercial buildings.

You're seeing them more often in commercial building because of the very
high ceilings involved. Those are 400W lamps. It would take too many
fluorescents to light a warehouse.

The only lights that
beat them for efficiency are the high pressure sodium lights (the ones that look
very orange); metal halides have a more natural-looking spectrum so win out
over sodium for indoor lighting.

Low pressures sodium are even more efficient and look *much* worse. :-)

Best regards,
Bob