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T-8 lamp and ballast questions (fwd)

>1. Sylvania's website indicates that their .88-.90 
>ballast factor units provide a 30-40% cost savings 
>over 40 watt T12 bulbs.  In generic terms, how does 
>the light output of a 32 watt T-8 with electronic 
>ballast fixture compare to cheap shop light T-12 40 
>watt fixture?  

You get quite a bit more light output from a 32w T8 then you do from a 40w
T12. Flourescents get more efficient as the tube diameter decreases, which
is why T5 bulbs are even better than T8's, but are only available in tiny
sizes. The exact % improvement in light output per watt of power input for
T8s over T12s is listed in the krib archives somewhere. Might take a while
to find it though, there is a *LOT* of info on this topic in there.

>2.  From somewhere in the archive, paraphrase...  T-8s
>don't degrade as quickly as T-12s.  It isn't necessary
>to do a T-8 bulb replacement on a 6-12 month 
>schedule.  Is this true?

Somewhat. In my expierience they do last longer, but not significantly so.
You don't start seeing the really big jumps in lifetimes until you get into
CF and especially MH lighting (where one lamp can last a few years). I'm a
big MH fan though so I'll try to hold back and not get too far off topic
here :-)

I don't think a T8 will go much past a year without a noticeable amount of
light dropoff. I've never tried running one into the ground though.

>3. Jamie Johnson asked in 1999 “It seems the instant 
>starters produce more lumens/watt, but with a 
>reduction in lamp life, which is ok, I change every 6 
>months…”  His question wasn't answered as far as I can
>tell from the archives.  Do the instant starters 
>produce more lumens/watt?  Is it significant?

Can't say much here -- I haven't really done much of a comparison. The
instant starters do shorten lamp life a bit, but you're going to be
changing tubes before they fail from instant-on use to keep up light
output.

>4.  Where can I buy the ballasts on line and who has 
>the best prices?

You will probably find the best prices at a commercial electrical supply
house. If you're around the Detroit area in Michigan I suggest trying
Madison Electric -- that's where I get all my ballasts. The last ones I got
were 175w MH ballasts, and they were about $18/each. Remember that most
"wholesale" electrical supply houses will sell to anyone (just go into
willcall and tell them you don't have an account), they just don't want to
explain products to customers like home improvement stores will do.

>5.  Just out of curiosity, has someone already done 
>the legwork of finding the cheapest .88-.90 electronic
>ballast for either a two or four bulb model from an
>on-
>line retailer?  

Thought about this about a year ago when I switched by smaller tanks over
from older flourescent technology (basically I got tired of replacing
starters and wanted starterless lights). I looked at T8, CF, and MH. MH was
obviously way overkill for 20 and smaller tanks (but great on big tanks!),
and T8 didn't have enough power for the size of the bulb to fit in a nice
hood. I ended up using CF lights and got around most of the ballast issues.
AH Supply makes nice kits. I seem to get about 1.5 years out of the 55w
bulbs I'm using too. If you're thinking about redoing all your fixtures I'd
look at CF and maybe MH too if you have large tanks. CF is probably the
best overall, and MH will be cheapest in the long run if your DIY since the
bulbs last a good long time.

     -Bill