There is/was some good info on flouro lights,and CFL's here:
http://sound.westhost.com/lamps/index.html
I can't seem to find the article I'm thinking of,however.
I am finding some flawed measurements, such as in:
http://sound.westhost.com/lamps/fluorescent.html
That page claims that an LED tube light produces more than twice as much
light per watt than fluorescents that it replaces, on basis of power
consumption and lux on a benchtop under the light.
However, the LED tube light is probably illuminating a smaller area than
the fluorescents did.
If you find benefit from making a light source directional, there is
such a thing as reflectors. With a suitable reflector, a decent fluorescent
will have the same directional pattern as the LED tube light and provide
similar (more likely greater) lux per watt than the LED tube light.
I am also finding some flawed data, as in:
http://sound.westhost.com/articles/incandescent.htm
That page has a table showing supposed overall luminous efficacies of
various light sources.
It shows 17.5 lumens/watt for 100 watt incandescent - that is top end
for 100W non-halogen 120V incandescent. And top end 230V 100W ones do not
achieve that, due to economies of scale on the thinner filament.
A few paragraphs later that page says a 100 watt incandescent produces
1800 lumens but clams CFL manufacturers are claiming 1246 lumens as
equivalent to 100W. In what country? Many European and Australian 100W
incandescents do only produce 1200-1400 lumens. 100W incandescents that
get referred to as GLS lamps (a term used on that page and where
household voltage is 230V) do not produce 1750-1800 lumens, and even USA
ones don't produce 1800 lumens.
Same story for the 40 watt incandescent.
It also shows 93 lumens/watt as "max, typical" for 36 watt T8
fluorescent. Keep in mind a couple things:
1. Most countries where most household incandescents are designed for
120V have T8 4-foot fluorescents mainly being 32 watt ones, and where
36 watts if the wattage of most T8 fluorescents most incandescents are
rated for 230V.
2. Catalog watt and lumen figures for T8 fluorescents are with line
frequency magnetic ballasts, while catalog figures for modern T5
fluorescents is with high frequency electronic ballasts. But most 32 watt
T8 fluorescents are used with high frequency electronic ballasts, which
largely eliminates one loss of most fluorescent lamps and reduces another.
I suspect that in new fixtures in Europe with 36 watt lamps, the ballasts
are probably mostly electronic.
The same table says 24 lumens/watt for halogen. Most rated at least
2,000 hours and drawing 2.5 amps or less achieve 21 or less.
That page also mentions some fixtures to not use any CFLs in. However,
some CFLs, such as Philips "triple arch" 15, 20 and 23 watt non-dimmable,
are specifically rated to be OK in recessed ceiling fixtures.
That page claims that CFLs emit significantly more UV than
incandescents. I have found that to hardly be true. And that page claims
that the UV increases risk of *breast* cancer?
That page also mentions problems from CFLs taking 5 minutes to warm up.
Ones without outer bulbs generally take more like 1 minute to be most of
the way warmed up.
I sense anti-fluorescent bias.
- Don Klipstein (
[email protected])