Thursday, June 21, 2012

Update on CFL lightbulbs

As an engineer who likes efficiency, I've tried a number of different CFL bulbs--probably about 100 in toto in the past decade or so--and figure that others wondering what to do in replacing lightbulbs (and electing politicians) might be interested in my experience.

The bulbs I like best are the simple bare bulb 60W equivalent in a "bright white" or "daylight" style; I've had to replace very few of them, and they seem to indeed last the full 5-10 years promised for such bulbs.  I still doubt that they actually last the promised 10,000 hours of use, but they at least do indeed save money. 

Second best are the 60W equivalent bulbs for recessed lighting--they also give you a few thousand hours of use, and really reduce the power needed to light a room.  Honorable mention goes to some three way CFLs I bought about a decade ago.  All of these lasted several thousand hours, even if I'm not sure that MTTF averaged 5000-10000 hours as promised. 

Bulbs to avoid; as far as I can tell, the rest of them.  Why so?  I'm not sure, but my hunch is that the bulbs are really designed to work at "60W equivalent", and when the design is "tweaked" to work at 75W, 100W, or 40W equivalent, the designers simply haven't done the reliability work to make them actually work well.

The worst bulbs I've seen are the small round and enclosed bulbs intended for bathroom vanities.  They literally do not last as long as the incandescent bulbs in the same fixture. 

So a word to the wise; 60W recessed and bare CFLs work pretty well, and the rest?  Well, write a letter to your Congressman letting him know that the claim that all CFLs work for 5-10 years is, to put it politely, false, and that he'd do well to lift the coming bans on incandescent bulbs if he wants your vote.  Or, for that matter, a well lit bathroom.


tobin said...

Thanks for the advice. I've avoided CFLs for the most part, but too have found that the single 60W one I have has lasted much longer than the couple 40W equivalents I have in some recessed lighting. I'll have to try 60W ones there and see if your theory holds up.

Bike Bubba said...

There may be some variance based on manufacturer, too; I've had really bad luck with "Lights of America," but really good luck with Phillipps and the Home Depot store brand.

Except for those 40W bathroom bulbs and such. Yuck.

And do remind people, if you verify what I've seen, that CFLs do not in fact uniformly last several thousand hours. Not true at all.

Gino said...

thanks for the advice. i trust you on this issue like i trust Brian on medical sciencey stuff.
(that is a compliment.)

Brian said...

That fits pretty well with my experience. When we bought our little bungalo in NC (2006) I replaced every bulb in the house (8 on the main floor, and another 4 or 5 in the basement, which we actually used quite a lot as extra living/work space) with the 60 W eq and every single one was still burning brightly when we sold it at the end of '09, except for the one on the back porch which we almost never turned off.

In a small house like that in the south, it didn't hurt to have less heat coming off the bulbs, either.

Our apartment in Seattle has a bunch of fanc(ier) light fixtures that require more exotic bulbs, and they have not fared as well.

Mark said...

I don't like having a pile of these things around when they fail. I'm unimpressed with the 3-ways, but they're a problem in the old version, too. The color quality has been poor with some putting out almost purple light. I use one for an always-on flag lighter and they seem to last a couple of years each.

Long story, short: I'm replacing the CFLs from the bag of incandescents that were replaced by the CFLs.

... And hoping I don't run out of 'em until there are reasonably priced LED replacements.

Bike Bubba said...


That is a small house!


Probably no reason to worry about the old CFLs. I looked up mercury toxicity when that furor broke out, and with an average "load" of about 5mG/bulb, each bulb has about half the amount of mercury needed to get a person to acute toxicity of around 1mG/liter of blood--and that assuming that the rest of the body doesn't absorb any. So unless you break the bulb and lick out the mercury, you should be OK.

I still agree that it would be nice if the law didn't make the choice for us, though.