TKM wrote:
wrote in message
ups.com...

wrote:
"...plus it only has so many starts in it
from the day it is built. They only save on longer duty cycles."

I understand that your concern is that a CFL will die too soon if you
keep turning it on and off too often. But note that the vast majority
of them come with a 5-7 year warranty. So if it breaks before 5 years,
take it back to the store, get your money back, and buy a new one.


Incandescant light bulbs are also affected by how many times they are
turned off and on. They will last for a substantially longer time if
left on continuously than if they are switched on and off for short
periods.

No. Think about flashing sign lamps, for example. Lamp life is similar to
non-flashing lamps.

Oh, really? What flashing lamps specifically are you talking about?
Like say am auto turn signal that from experience fail about as often
as say a headlight, even though the turn signal is only on a tiny
fraction of the time that a headlight is on?

If you watch the Mythbusters show, they actually tested conventional
filament type bulbs and concluded the life was significantly shortened
by how many times they are turned on and off. This only makes sense,
as each time you do it, you are taking the filament from cold to white
hot, which stresses it, just as any metal will be stressed by greatly
heating and cooling it repeatidly.

If you want more proof, here from the DOE:

http://www.eere.energy.gov/consumer/.../mytopic=12280

When to Turn Off Your Lights
The cost effectiveness of when to turn off lights depends on the type
of lights and the price of electricity. The type of light is important
for several reasons. All types of lights have a nominal or rated
operating life, which is the total number of hours that they will
provide a specified level or amount of light. However, the operating
life of all types of light bulbs is affected by how many times they are
turned on and off. The more often they are switched on and off, the
lower their operating life. The exact number of hours that switching
lights on and off reduces the total operating life depends on the type
of light and how many times it is switched on and off.



Only when incandescent lamps are near their normal
end-of-life does turning them on and off make a difference. That difference
is minor according to the research reports and amounts to only a few hours;
but it explains why lamps so often fail when turned on.

I'd be happy to see those research reports. And of course the extent
of the effect depends on how many times you turn it on and off. The
Mythbuster test was turning it on and off at least several times a
minute. It may be "minor", in the sense that the shortening of life is
way out weighed by the energy savings. Or that the typical light only
gets turned on and off a couple time a day. But that doesn;t change
the fact that incandescent bulb life is impacted by turning it on and
off, just like a CFL.



From the standpoint of cost, however, it's always better to turn a lamp off
if you don't need the light since the cost of energy to operate any lamp
designed for general lighting service is typically 80-90 percent of the cost
of providing light.

No one is arguing that it's cost effective to leave lights on. I'm
only saying that the more you turn them on and off, the shorter the
life.



TKM