On Apr 27, 8:24*pm, Tony Hwang wrote:
Joseph Meehan wrote:
* *I remember one college project was to figure out how long you needed
to turn out a standard the old 4 foot tubes before you would save money.
Factoring in the cost of electricity lamps and the labor for maintenance
to replace them, it turned out to be about 20 minutes. *We had a fun
statistics class back 35 years ago. * The CF's would be far less. *That
start up surge is like 1/30 of a second and is about 10 times or less of
the rated lamp consumption.

"bonnie" wrote in message
...

Given, CFL's are thought to be more energy efficient than incandescent
bulbs. But I heard they use more energy to turn on.

What if it is in a room that is used infrequently, a closet or guest
room for instance. In other words a room in which you would go in and
out of pretty quickly.

How long would a CFL have to be left on to realize the net energy
savings.

thanks for your input,
bonnie

Hmmm,
For start up normal ilament lamps creates surge current at the moment
it's on. Most any electrical load being inductive will do same.- Hide quoted text -


The inductance of a filament type bulb is negligible and doesn't cause
any surge. In fact, with an inductor the effect is exactly the
opposite. The faster the rise time of the incoming voltage waveform,
the higher the impedance, which restricts current flow.

The current being higher at start up is only due to the fact that the
filament resistance is lower when cold than when it's at operating
temperature.