On Sun, 22 May 2011 12:13:11 -0400, "Ed Pawlowski" wrote:


"Smitty Two" wrote in message
news
In article ,
"Ed Pawlowski" wrote:

The poster said the EE stated efficiency was the determining factor.
Therefore, he says the 49 watt output is what counts because it is more
efficient. He states that lumens is not useful. I say BS.

Which poster said that?

I may have interpreted that incorrectly It was between your friend's
statement and krw's reply that lumens are not as useful as efficiency.
My point is, though, efficiency is not as meaningful as actual light output,
no matter the measurement method.

Yes, if you measure the power in the (visible) light output you have *both*
the light output *AND* the efficiency (watts in is already stated).

Sorry, but the fellow who told me that is a life-long EE, and one of the
world's leading laser experts. While watts as used in connection with
incandescent lamps has always referred to consumption, the light output
can also apparently be measured in watts. I choose to believe my friend,
whom I've known and respected for 10 years, on this score.

Absolutely. Watts-out/watts-in gives efficiency directly. W/lumen gives a
relative number but not as useful.

Watts-in/watts-out also shows how inefficient light bulbs really are and give
an incentive to increase efficiency. Maybe more reason for people to switch
(not enough for me, though ;-).