Sean wrote:
One other question while on the topic of replacing ballasts and
fluorescent
lights....
I am remodelling an empty unit to make a bookstore and they currently
have
about fifteen to twenty 8 foot double tube lights throughout the
store. (The
store is about 2500 square feet.)
I am considering replacing them all with about 50% more 4 foot units.
(So
about 22 - 30 units.)

Here, Britain, 8' tubes are mostly 125w, with some being 100w.
Presumably youve got 60w 8'. Basically the longer the tube, the better
the efficiency.


I am considering doing this mostly due to the high price of 8' tubes
and
ballasts.

.... you have all the 8' ballasts already, no extra spend needed. Re
tubes, they last long enough for there to be no hurry, if you have
anough that work now.


(In this part of Canada the 4' tubes go for about $1.40, while the
8' go for about $6-$7). Also the ballasts for the 8' bulbs costs
about $30,
whereas I can get a whole 4' unit for about that price. ($20 for a
cheaper
one that will probably break down in a few years, $30 - $35 for one
that
will hopefully last.)
So there are actually two questions:

1) Will I retain a similar amount of light from replacing those
units? (I
know that their will be a small drop in light, but I just wanted to
know how
noticeable it would be? Or should I just double the number of 8'
units and
achieve near the same amount of light?)

2) Is it going to be cost effective over 10 -15 years to replace all
these
units? (Or am I wasting a lot of money trying to avoid spending $6 -
$7 on
the 8' tubes and $30 on a few new ballasts to replace the 3 or 4 that
are
burnt out?)

Thats the impression I get, but do the numbers. What does it cost you
to fix he few 8'ers and provide tubes, what does it cost for 4'...

I'd look at just replacing a small number with 4', just as needed, but
do it in one area to ensuer it looks decent, using the good 8' lamps in
that area to repair or replace the dead ones elsewhere.


NT