compact flourescent bulbs - energy question

General Questions
#1

Back in 1980, the straight dope column gave an answer about turning light bulbs on and off. In the era of compact flourescent bulbs, I’m wondering if that answer has changed at all.

So, how much power does it take to turn on a compact flourescent bulb? compared to an incandescent? compared to an LED?

Is 15 minutes still the rule of thumb for for turning lights on and off? Meaning, if I expect to want the light back on within 15 minutes, I should just leave it on.

Thanks for the help. I have not been able to find any online resources that answer my questions.

#2

Would it help if you spelled it “fluorescent”?

#3

sorry I mispelled it here in my posting. I’ve actually searched the web using both the correct spelling and the incorrect without and luck. That’s why I resorted to posting here.

FYI, There are lots of sites that have it misspelled. I will endeavor to spell it correctly now.

#4

I’ve heard the same thing about fluorescent light fixtures, i.e. if you’re going to return within 15 minutes (or whatever), you would actually use less energy by keeping them on. The reason for this is due to the “in-rush current” when you first apply voltage to the fluorescent light fixture. The in-rush current means the fixture will consume a lot of power when starting, and the power decreases once the bulb lights. An analogy is a bird taking off… the bird expends a lot of energy to get off the ground, and its energy usage decreases after it is in flight.

I have no idea what the “break even” time is, but my guess is that it’s probably a lot less than 15 minutes. Also keep in mind that incandescent bulbs also have an in-rush current.

#5

… Large office and production facilities balance the cost of electricity for the time lights are left on during periods of non-use versus the cost of lamps and labor for replacement.
Some chain stores replace ALL the lamps in a store at one time and then replace burnouts periodically for several times.
For an individual and one lamp or two or three it proably doesn’t make a whole lot of never-mind.