In article , Nate Nagel wrote:
Don Klipstein wrote:
In , Blattus Slafaly £ ¥ 0/00
wrote:

Don Klipstein wrote:

In ,
N8N wrote:

On Feb 18, 9:08 am, "Blattus Slafaly £ ¥ 0/00 "
wrote:

Get rid of all that hardware and install some sockets with compact
fluorescents.

I'd rather not do that; this is a basement with a low (7 foot or
thereabouts) ceiling with a drop ceiling below it. Any decrease in
headroom will be an invitation to bonk your head, and I don't want to
go to can lights because they'd probably be less efficient.

Can lights are definitely less efficient. Also, keep in mind that
compact fluorescents tend to overheat in can lights, unless you get ones
that are known to be good for such heat hellholes.

In general, compact fluorescents have about 2/3 the efficiency of T8
4-footers, don't last as long as 4-footers, and cost more than 4-footers.
Use T8 when you can.

- Don Klipstein )

But you can replace the compact fluorescents with Super Bright LED's as
the price comes down without rewiring. They run cold and can give you 40
incandescent watts at 7 watts usage and last 20,000 hours.
http://www.superbrightleds.com/led_prods.htm


Are you talking about the E27-CW8?

I don't see a 7 watt one, and this one is closest at 8 watts. Claimed
light output is 385 lumens for the cool white, 365 lumens for the warm
white. Color rendering index is 77 for the cool white and 76 for the warm
white. Price is $49.95.
And that one is some sort of floodlight or spotlight.

Compare to a 9 watt CFL, which produces 440 lumens, has CRI of 82,
is rated to last 7,500-10,000 hours nowadays, and costs about $4.

Meanwhile, a T8 32 watt fluorescent produces about 2500 lumens, even in
"average age and condition" when used with a ballast with ballast factor
of .9, with power input to the ballast typically 28-30 watts. Color
rendering index is 84-86 for the higher of the two common color rendition
grades, average life expectancy is 20,000 hours, 24,000 for longlife ones,
and they cost about $2-$3 apiece.

It's going to be quite a while before LEDs make T8 fluorescents
obsolete. It looks like a few years before they get competitive with
compact fluorescents even.

- Don Klipstein )

Just for the record, the fixture I am using holds four F40 T12s. Again,
it is sort of the "fixture of opportunity" as they were free, and I
needed to do something to replace the horrible mess hiding above my
ceiling. I was originally planning on using three 2x2 troffers but the
2x4s were free so I will use two of those instead.

Probably a good move!

4-foot F40 T12 with magnetic ballasts of 30-plus-year-old technology
still has energy efficiency ahead of compact fluorescents, as long as the
ballasts are at least "commercial grade" so as to give a full 40 watts to
a "true 40 watt F40", and your F40's are "true 40 watt".
With favorable temperatures and if the ballast labels explicitly allow
for 34 watt "energy saver F40" (or are rated for both F30 and F40 T12),
you can use 34 watt "energy saver F40" to get a little more energy
efficiency still than with "true 40 watt" F40 lamps. Just beware that
those tend to be more intolerant of cold than "true 40-watt F40", and to
some extent or another to be "generally a little more cranky" than "true
40 watt F40", and to be mainly available with lower color rendering index.
The USA legislation that partially bans "true 40 watt F40 T12" has an
exemption for higher color rendering index. Color rendering index near or
above 90 generally necessitates a compromise in energy efficiency, but
there is something that has fairly high color rendering index to be
allowable as "true 40 watt F40" without compromise of light output and
energy efficiency: Philips Ultralume! The "cool white color" is referred
to as 4100 or 41 (nominal correlated color temperature 4100 K).
The color rendering index of these is 84. Furthermore, these are
upper color rendition grade triphosphor ones whose color distortions tend
to be majority in the direction of "colors more vivid". Fluorescent lamps
withy CRI near 90 or from low 50's to close to 66-70 tend to have their
color distortions mostly in the direction of "colors less vivid".

- Don Klipstein )