I currently have some CFLs that ran for a year 24 hours a day, and 7 months 12 hours a day, so they have lasted well past their 6000 hour rating, going on maybe 11,000 hours
I’ve seen this on other bulbs as well in the past, so i’m drawing the conclusion that the on/off cycle is what is responsible for shortening their life (Leaving out the cheaply made ones that would fail in a year no matter what).
Does anyone have an idea how much turning them off and on shortens their life, in hours? Say one cycle reduces life by 5 hours.
Also is it the turning on or the turning off that does the shortening or most shortening?
on off must be it, most of the CFLs i use blow up within 2 years, a don’t recall having one last much longer than that. Infact, i just had one go Boom crackle and smoke on me today, only lasted maybe 4-5 months, could be less, but the bulb came with the floor light, and this light cycles on and off A LOT, there is a total of 5 bulbs, and 3 modes, 2 on, 3 on, all 5 on then off, and every time you cycle the modes the light goes on/off like LED flashlights with the tail switch cycle. and you have to cycle to the “off” mode, so to just turn the light on once and off once, the CFLs has to flicker at least 2-3 times, so the cycles really add up quick
man one hell of a run on sentence
High temperatures are a problem for CFL’s.
If the light fixture is very small, and if the heat can’t get out, CFL lamps will have a very short lifetime.
Here is a YouTube video of a MythBusters episode that deals with this question
at 4:30 of the video they deal with the constant on-off of various types. Only leds seem not to be affected.
Fair enough, now i wonder if there is a number, like i mentioned above, maybe 5 hours of life for each on/off cycle?
IME, cfl’s require continual energizing for the maximum life-span.
GREAT for outdoor lighting, okay for rooms that are used occasionally, and reALLy bad for bedrooms.
when CFL turn on, its two filaments energized. so each turn on cycle add some wearing to filaments.
this is far more wear & tear than keep CFL on for long time.
I saw some interesting behavior
CFLs which turn on faster, have long life. & technically it mean low turn on time -> low filament wear.
(there is a current flow though filaments until gas ionized and tube become conduct)
Interesting paper on the subject
http://www.eco-shiftpower.com/PDF/white-paper.pdf
I remember reading that a lot of the failure in CFL and even LED bulbs is in the electrolytic capacitors. They can last as short as 2000 hours before electrolytes evaporate.
i was told a fairly similar thing by my energy efficiant living teacher when i did my electrical pre-app
every time the bulb is turned on it burns a minute amount of fluorescent/ (phosphor?) and when it runs out it no longer starts
Geez! Why do I keep reading “CPF Lifeline”… 
Anyway, I think that the old CFL were better than the current offerings, I had 3 burn out in a 2 year period, while 14 other CFL’s bought back in 2007 are still going strong, all my bulbs are GE brand.
A annoyance I have is that some of the new bulbs start rather dim and brighten up after a minute or so, while the older ones seem to start at full brightness, anyone else noticed?