"Home Guy" wrote in message ...
Tomsic wrote:

Yes, T8 bulbs are more efficient.

At a higher operating temperature.

And tell me why the exact same process or formulation they're putting
inside T8's can't be done with T12's such that we don't need this
god-damn stupid game of having different ballast requirements.

The reason is cost, cost and cost. More costly phosphors have to be used in
T8 lamps because of something called "wall loading" which means the phosphor
particles are exposed to more watts/phosphor area. T8 phosphors can take
that pounding; T12 phosphors cannot and lose light output fast. Good thing
that T8 lamps have less inside glass area than T12s so less phosphor is
needed.


Check any lamp manufacturers lamp catalog. The nominal light output
of an F40T12 (40 watts) is about 3000-3100 lumens. The nominal
light output of an F32T8 (32 watts) is the same 3000-3100 lumens.

For one thing, show me where you can even buy 40-watt T12's.

I'll take a 34-watt T12 any day (at $1.25 each) over a 32-watt T-8 (at
$3 each) any day.

Just don't handicap me by making 4-lamp T12 electronic ballasts
artificially scarce and expensive while 2-lamp versions are strangely
cheap.

4-lamp T12 ballasts are scarce because hardly anyone wants or buys them.
2-lamp fixtures outsell 4-lamp fixtures by a wide margin. Just count the
2-lamp and 4-lamp fixture types that you see walking around any office
building or school. Another consideration is that if one circuit in the
4-lamp ballast fails, the whole ballast has to be replaced. It doesn't make
sense to throw away a 4-lamp ballast which still partially works or try to
add an additional 2-lamp ballast to the fixture to get the lamps on the
failed circuit working.

F40T12 lamps are being phased out in favor of T8 lamps

Because of mercury. That's the ONLY reason.

Not it's not. A T8 lamp/ballast system is 10-15 percent more efficient than
a comparable T12 system, so the phase out is mostly cost driven with some
federal regulations in 2005 and 2007 from the DOE moving it along. The
slightly higher initial cost of a T8 system is usually paid back in 3 years
or less. But, the rising costs of T8 lamps (due to the restriction of
rare-earth phosphors by China) have increased the payback times. U.S. lamp
manufacturers asked for and received a delay in the DOE lamp phase-out
process last year as a result.


And again, the standard T12 lamp has been 34 watts for a long time.
Saving 2 watts (and paying triple for it) doesn't make any sense.

I'm going to stock up and buy a few boxes of 30-count T12 lamps.
Because those will be the real prize to have in the future - not
100-watt incandecent bulbs.

I'll still bet on the most efficient system being the cheapest in the long
run because the one cost that's not going to go down is the cost of energy.
Ballast and lamp prices change all the time and that market is very
competitive, but if you end up with a system that uses more energy than
something comparable, you'll end up paying more. With incandescent
lighting, 90% of the cost over the life of the fixture, including
replacement bulbs, is energy. With fluorescent systems, it's a bit less;
but when you buy and install any lighting system, you automatically contract
with the electric utility to power it -- or pay to do it yourself somehow.
In any case, there's an energy cost involved with a big number attached to
it that usually overwhelms the cost of the ballast or tubes. All you have
to do is pay the electric bill and wait.

Tomsic