Are advertised lifetimes of CFLs true ?

I have been buying CFL light bulbs for more than 6 years now. Most of the time the life printed on the package is greater than 8 yrs but I have never seen them live that long especially the daylight kinds and the floodlights which last anywhere from 6 months to 2 years. I’ll admit the soft whites last around 4 years. So what’s the straight dope on their life expectancy ?

Am I doing something wrong or is it faulty advertising or both? I have a house built in 2007 and the sockets / switches are rated for CFLs.

Mine average about 2 years but I assume it’s because the wiring was probably installed in the 50’s.

As I recall from a Consumer Reports article, they are like most products: some brands are high quality and last the promised lifetime, some are low quality products.

You know, I’m not sure I’ve ever had one burn out. I started using them when it got difficult to get incandescent bulbs, and jeez, the price! But they apparently last forever, or that’s what I tell myself. I keep a pack around and replace the old kind when they go. I think I still have a couple of lamps with incandescent bulbs left.

No, I take it back. I somehow inherited an early-model twisty bulb from my Grandpa. It was quite a bit larger than the kind you get now, and it did finally burn out.

"CFLs typically have a rated service life of 6,000 to 15,000 hours, whereas standard incandescent lamps have a service life of 750 or 1,000 hours.[15][16][17] However, the actual lifetime of any lamp depends on many factors, including operating voltage, manufacturing defects, exposure to voltage spikes, mechanical shock, frequency of cycling on and off, lamp orientation, and ambient operating temperature, among other factors.[18]

The life of a CFL is significantly shorter if it is turned on and off frequently. In the case of a 5-minute on/off cycle the lifespan of some CFLs may be reduced to that of incandescent light bulbs."

I have CFL bulbs all over the house, and I assure you they do NOT last any longer than regular incandescents nor has my electric bill dropped in any way. Big scam, IMHO.

Maybe time to switch to LEDs

What possible difference can the house wiring make? Current is current.

The one CFL I tried was nowhere near its advertised brightness. It said it was 23W, but the equivalent to a 100W bulb in brightness. When I actually measured it, its luminosity was closer to … 23W. I am holding out for LCD. Yes, they are expensive and, so far, I’ve not seen very bright ones, but I keep hoping. And I won’t have to take them to the toxic dump when (and if) they burn out. What a boondoggle!

That’s really weird. I can think of a few things that might have affected your results: First, maybe your light meter was only sensitive to a few particular wavelengths of light. CFLs tend to emit a lot of light at just a few wavelengths, rather than a smoothly varying amount across all wavelengths. See the spectra here, for example. If your light meter was only measuring in the yellow or the blue-green part of the spectrum, that might well throw off your results.

Second, CFLs do take a few minutes to fully “warm up”. CFLs use mercury vapor to produce their light, but the vapor tends to condense at room temperature. So when you first turn on the bulbs, they don’t have quite as much light-producing power available until they warm up a bit. If you turned the bulb on and immediately measured the light available, then it would have been less light than advertised. A corollary of this is that CFLs are not really well-suited to locations where they’re only run for a few seconds at a time (such as closets), or to locations where they get really cold (such as outdoors in Minnesota.)

Finally, maybe you just got a crappy bulb. As noted above by, some bulbs are better than others.

Oh, and one other thing occurs to me: of course it’s true that CFLs only emit about 23 watts or so of energy as light. So does a 100-W incandescent bulb. The purported advantage of a 23-W CFL is that it doesn’t emit 77 watts of heat like an incandescent bulb does.

I filled my house’s light sockets with them in 2004-2005. The only ones (about three of them) that have burned out so far were ones I bought for a dollar or two at flea markets or no-name dollar stores. All the ones I bought on sale at Lowe’s (they had a big sale when they switched the brands they sell) are doing just fine.

I have one that has lasted eight+ years.

When I moved to my present apartment nine years ago, it had incandescent bulbs in all of the overhead fixtures. CFLs were a fairly recent thing on the shelves and much more expensive, but as bulbs burned out I used them for replacements. The one in my bathroomwas replaced in early 2005 and is still going.

When LEDs become reasonably priced, I’ll likely switch to them. I already have a couple as work lights and love them.

Quality CFLs can last much longer than their advertised life. I have one in my outside entryway fixture that is on every night for over 12 hours, and it hasn’t been replaced in 5 years (22,000 hours). I’ve had others die very quickly, but they were always lamps that advertised high output in a small package - they run very hot, and that shortens their life. I’ve run CFLs for 20 years, so it’s hard to say how much money I’ve saved, but a quick calculation show that just the outside light saves around $2/year (not to mention the cost of replacing light bulbs). I’m slowly switching to LEDs. Interestingly, LEDs are efficient enough that it’s justifiable to replace CFLs with them. I just upgraded to a 9.5w Cree LED to replace a 13w CFL that’s on 24/7/365 - the 3.5w difference gives a 2-3 year payback. I’ve taken to writing the install date on the LED bulbs, and keeping the warranty card and receipt.

as mentioned quality brands last longer.

individual units can vary either side of an average.

i have a preCFL CFL (a circular tube [the size of the smaller bulb in an old two bulb kitchen fixture] on a support with a ballast and a screw base) that still lights up.

Lighting is typically a small part of your electricity usage, and delivery charges and other fixed items a large part of your bill.

So a 50% drop in your lighting cost could easily be very small drop in your bill.

After we moved into this house in 2001, I switched to CFLs as bulbs burned out, over a period of three or four years. In that time, six of the CFL bulbs have failed. Two were the ones we put in the porch light and the garage (I finally figured out not to put indoor-rated bulbs outside), one was an older bulb I’d used in the previous house for a few years, so it had probably been in use for six years total, and one was a defective, cut-rate bulb. The other two were bulbs I’d used in the upstairs hall lights - lights we turn on and off very frequently and rarely leave burning for more than a few minutes at a time. That’s the only fixture I’m keeping an old-style bulb in, and it’ll probably be the first one I put an LED bulb into, once prices come down a little.

As an aside, I hated LCD bulbs when I first tried them, but once I figured out that I could find them in different color temperatures and tested one that had a similar range to an incandescent, I came around. The ones that are around 3000K work for me; ones that are advertised as “sunlight” (above 5000K) make me want to hang myself. Once I learned to buy bulbs accordingly, I was a convert.

I’ve yet to find a CFL that paid itself by lasting longer than incandescent light.
I’m thinking of returning to traditional bulbs. The light is better (for me), it’s instantaneous, less polluting.

CFLs are 2/$1 here - how much are incandescent bulbs (I haven’t bought one in a decade)?

I agree–they pay for themselves in the first year just by their energy savings. The extended life is just a bonus.

It’s mostly the inductance of the house wiring that makes a difference. Long cable runs (and poor spur architectures) make for high inductance, which causes a big voltage spike when the circuit is switched off. This can often be seen as a big spark in the switch as the contacts arc over when opened. CFLs also have a large inrush current when turned on, which reduces the lifetime of older switches designed for incandescents.

The lifetime figures for CFLs are usually calculated for the bulb in a glass-side-up orientation (so the drive circuit in the base runs cooler), and with minimal on/off cycling. Plus a bit of optimism and massaging of the figures (see also “equivalent brightness” specs). Dangle one from the ceiling and switch the thing several times a day and the lifetime figure drops dramatically.

Early CFLs used to last longer, but now they’re a commodity and the usual race-to-the-bottom to compete on price means that they’re pretty much all low quality now.

I could go on all day about these hateful things. LEDs will eventually make them obsolete, though even these have issues to be solved. I like to use LEDs in place of < 40 W incandescents, and mains voltage halogens for anything brighter.