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Re: CF lamps
Steven Dixon <stdixon at ben_bechtel.com> sez:
> Just to make a stupid observation of my own, all seem to agree that the new
> T-8 bulbs are more efficient, which I take to mean that T-8 bulbs put out
> more light per watt (again, I'm not sure if we mean lumens or PAR when this
> is said) than the old T-12 bulbs. So perhaps simply saying that all of
> these bulbs use the same technology doesn't really answer the efficiency
> Does anyone have a definitive answer to this question? Do CF bulbs put out
> more light per watt (lumen or PAR) than regular fluorescent bulbs; than T-8
> bulbs? Do we have data on this point?
I have manufacturer's data (Philips's Lamp Specification and Application
Guide), but I dunno how much info you really want. All of these specs will
be with the new 835 phosphor because it is available in all sizes. The 840
and 850 phosphors produce the same lumens per watt as 835. Linear T5 lamps
have an efficiency of up to 105 lumens/watt, but I've never actually seen one.
F40T12 lamps in the SPEC35 series produce 3200 lumens (80/w) and the 34w
"econowatt" equivalent produces 2800 lumens (82/w). This is a lot better
than the old "cool white", which I can't find good data for anymore for 4'
The F15T8 lamps in SPEC35 produces 940 lumens (63/w), so you can see the
affect of the shorter arc distance. The same F15T8 in the old "cool white"
produces 870 lumens (58/w).
The new T8 lamps are better. The F32T8 with 835 coating gives 2950 lumens
(92/w), and there are premium lamps available that do 3200 lumens, for that
magic 100 lumens per watt.
Compact fluorescents fall in-between the T12's and new T8's. The little 13W
with a GX23 base gives 825 lumens (63/w). The long tube CFL's do a lot
better. The 36W lamps that are 16 inches long produce 2900 lumens (80.5/w).
The 40W lamps that are 22" long actually use 38w and produce 3300 lumens
(87/w). The 50W lamps produce 4300 lumens (86/w). My book does not list the
55W nor the 96W CFL's.
Hopefully you can extract something useful from all this.