Go towards the light Carol Anne!
December 22, 2007 5:38 AM   Subscribe

Is Al right? Am I really saving the environment by switching to CF bulbs?

My wife and I, like most folks, have jumped on the compact flourecent bandwagon. In doing some more research, I've come to find out that while, yes, you can save a ton of energy in your home by switching, there is, like most things, more to the story.

The Energy Star folks tell us to leave the bulbs running for at least 15 minutes per use even if I would normally just switch the light off when I was leaving the room. There's mercury in them (yeah, there's mercury in coal, but only half of US electricity generation is coal fired). There are more parts to them requiring more energy to produce them. My house's heater has to work harder to make up for the loss of incandecent bulb heat (inversely of course the AC works less)...

So, what's the deal? Is there definative, accurate, mostly unbiased information that compares the actual and entire environmental impact of the various forms of lighting available, incandecent, flourecent, LED, halogen, big red tallow candles mounted on human skull sconces, etc...?

Please scienticians, male answer syndrome sufferers, environmental wack-os, global warmng deniers of the hive mnd set me on the right path!
posted by Pollomacho to Science & Nature (44 answers total) 3 users marked this as a favorite
Well I may not qualify as a wack-o, exactly, and I do love my Mother (Earth), but I say ignore Al on this one. Love that luminescent glow and hate the harsh flourescent light.
posted by Rain Man at 5:55 AM on December 22, 2007

My house's heater has to work harder to make up for the loss of incandecent bulb heat

True, but an efficient central heating system can produce the same heat with far less energy than the lightbulbs though, so the drop of energy being used by the bulbs is not made up by extra energy into the heating system (if you're using electrical heaters, this will be a closer call, but you're not likely to be using MORE energy to make up the lost heat by not using bulbs ;-)).

In our house, at least, we save significant amounts of energy. We've managed to replace most 100W bulbs with 11W versions, and the dimmer bulbs with even lesser ones. Considering 11W is 9.1 times less than 100W, there's a lot of leeway there! I'd say we probably leave the bulbs on 50%-100% more than the old type of bulb, mostly due to this efficiency, but even so it's still a good 4-5 times less energy.

I'd like to see if anyone has any numbers on the environmental cost of production though. Since CFLs last several times longer than regular bulbs, I'm guessing that even if the CFLs have several times more environmental cost in production, it still balances out at that level.
posted by wackybrit at 5:58 AM on December 22, 2007

Oh, and I see that light quality argument in lots of places.. and I don't know if the US has particularly poor CFLs compared to Europe, but the CFLs we have are "warmer" (light wise), I'd say, than regular bulbs. Certainly more amber / orange in their glow whereas regular bulbs tend closer to pure white.. and we just use the cheapest energy saving bulbs we can find.
posted by wackybrit at 5:59 AM on December 22, 2007

I just switched over to CF bulbs and have been completely unimpressed - the light was unpleasantly bright and cold. According to my friend, who had also recently switched over to CF bulbs, you're supposed to wait 15 minutes for the light to "warm up." So I waited, and all that happened is the light started to flicker. A lot. That was even more annoying and actually seemed a bit dangerous.

As I found them unbearable for use inside, I put on in an outdoor light fixture, and the bulb doesn't light up immediately - maybe they don't work well in the cold?

So I'll be watching this thread with interest. I'm all for saving money and helping the environment, but not if it hurts my eyes, makes me cranky, and could potentially set my house on fire.
posted by suki at 6:35 AM on December 22, 2007 [2 favorites]

My CF bulbs seem to require a warm-up time of a few minutes to produce a pleasant quality of light. At first it is very ghostly before they power up. In my workspace, I use a mixture of daylight and regular CF bulbs to get a reasonable 'white' light.

Supposedly, the mercury in the bulbs is less than the mercury that would be liberated by the extra electricity that would be used to power incandescent bulbs [no citation]. But the thing I worry about is breakage, with that mercury vapor let loose in my house for my family to breathe. Hasn't happened to me yet though, and maybe there's some breakage safeguard in them that I don't know about.
posted by DarkForest at 6:44 AM on December 22, 2007

Oh, and the ones I've gotten recently don't have that annoying 1-2 second delay before lighting up that older ones had.

I still have a mix of incandescent and CF bulbs in my house. They'll have to get a bit better before I'm likely to completely switch over to CF.
posted by DarkForest at 6:48 AM on December 22, 2007

You guys are either a bunch of pampered babies or buying crappy bulbs. We have converted over as many as we can, using the crappy ones in basement areas etc. that don't matter and nicer but more expensive ones in the main living areas. A good CF bulb throws as nice a light as most incandescent bulbs. It saves a lot of electricity.

The original question though is does it save the planet given the Mercury. Some studies suggest that incandescent bulbs are even worse here.
posted by caddis at 6:55 AM on December 22, 2007

Since they burn out less frequently, we don't have to produce as many, even if each bulb requires more energy/resources to produce. Plus, less risking a broken neck trying to open that ceiling fixture.

Overall, I think the risk of a house fire from a fluorescent is far less than from an incandescent. Fluorescents are mostly a risk if they're improperly installed (you didn't twist it tightly enough, perhaps? or the socket wasn't able to cope with it?) which is at least something that only needs to be checked infrequently. Incandescents can (and do) cause fires all the time because something was left carelessly and leaned against the bulb, or because the light leaned/fell over, or because children draped something over the light (do remind your kids that hanging a blanket from a light is NOT a good way to make a play fort).
posted by anaelith at 6:57 AM on December 22, 2007

Three way CF
Dimmable CF
posted by caddis at 6:57 AM on December 22, 2007

O.K., what is a non-crappy CF brand that has decent start-up time and good (or at least acceptable) indoor light quality? We've tried a few brands, and they've all sucked, where "suck" means either slow startup; crappy, depressing light quality; or far shorter lifetime than advertised.
posted by dws at 7:35 AM on December 22, 2007

I've never had a problem with the quality of light from CFLs. It could be because all of my bulbs are covered by shades, or maybe I just don't care what color my light is. Wikipedia says the new "soft white" CFLs are now similar to standard incandescent bulbs.

The 15-minute warm-up is to prevent rapid power-cycling, which reduces the life of the bulb. I've never noticed a flicker from CFL's.

As for the mercury, that's getting better too. Philips' Master TL-D Alto are supposed to have the lowest amount of mercury, at 2.0 mg. If you recycle the bulbs properly, most of that mercury will be recovered anyway. A little googling or a call to your municipal government's information line should tell you where to take them. Regular fluorescent tubes also contain mercury and should be recycled.

There's been alarming stories lately of broken CFLs requiring HazMat teams and thousands of dollars for cleanup. Not exactly the case, says Snopes, but you should ventilate the room, collect all the broken pieces with cardboard and tape (not a broom that would be contaminated), and box up everything (broken pieces, cardboard and tape) to deliver to a facility that recycles CFLs. You might want to avoid using CFLs in floor or desk lamps that might get knocked over, especially if you've got kids running around.

LED bulbs show a lot of promise. They're expensive and not as powerful yet. But we can expect a lot of new lighting designs that take advantage of them, like Herman Miller's Leaf Light.
posted by hydrophonic at 7:51 AM on December 22, 2007 [1 favorite]

I tended to replace 60W incandescents with 25W CFLs, which are the equivalent of 100W incadedescents. (I feel the 15W/60W-equivalent CFLs are a little too dim.) Other than that, I love them, and yes, they're the real thing. As of this week, incadescents are officially being phased out and will be banned by 2013.
posted by gerryblog at 8:18 AM on December 22, 2007

"Incandescent" isn't even that hard to spell. Sorry about that.

I do wish that they'd publicize the proper cleanup information a little more. The one time a CFL broke while I was putting it in, I kind of freaked out until I found reliable info on the Web.
posted by gerryblog at 8:19 AM on December 22, 2007

A lot of people are talking about the quality of light, but that has nothing to do with whether you're saving the environment or not.

Here's a what a lighting guy told me, not too long ago, at a party: "Compact fluorescents? Bullshit." (His words.)

Well, not entirely. He went on to qualify that statement by saying, yes, CFL's do absolutely save YOU money on the amount of electricity that you use and have to pay for, so they are worth something on the consumer end. But CFL bulbs require a ballast and because most lighting fixtures aren't built with integral ballasts, this means every bulb you purchase has to come with its own, and every time you dispose of it, you're disposing the ballast along with it. In other words there is an energy cost associated with the manufacturing and disposal of a part that could just be built into the fixture to begin with, and this cost is completely invisible to consumers. So CFL's will really start pulling their weight when fixtures are designed with ballasts (the way those industrial fluorescent panels are, you just switch out the tubes) so that the bulbs don't need them anymore.

Unfortunately, I don't know whether anyone's actually studied this in depth, or if this is just A Lighting Guy's opinion.
posted by lou at 8:51 AM on December 22, 2007

I'm concerned about the 15 minute rule. From what I read on the Energy Star website, CF bulbs are best for places where they'll stay on for fifteen minutes at least a 15 minute stretch (http://www.energystar.gov/index.cfm?c=cfls.pr_cfls), but that's not the same as saying that bulbs should be on for fifteen minutes. I think it means that they're lousy for places where bulbs are never on for long periods of time. So if you're diligent about keeping the light off in the bathroom, and you take only 5-minute showers, there's no real benefit from CF bulbs. There's still no downside, seeing as they'll still last longer than incandescent bulbs.

Based on the ever-reliable Mythbusters study, the initial power surge for turning on a bulb of any variety (with the exception of tradational, long-tube florescent bulbs) is offset in less than a second. You don't save electricity by leaving your lights on, even if you're leaving the room for just a minute or two. Unsurprisingly, turning off lights saves electricity.

You probably all understood that already, and I'm both obvious and slow. Sorry.

BTW, CF bulbs from Wal-Mart give off a horrible, bluish light than makes everything look awful. On the positive side, you'll eat less because your food looks unappetizing, but on the negative, you'll never get married, either, because everyone you know will be uglier under those lights. They're cheap, but man are they awful.

I've had much better luck with CF bulbs from Costco. Nearly (but not perfectly) equiv. to incandescent bulbs though, yes, they do take longer to warm up to high-quality light. We deal with it.
posted by terceiro at 8:51 AM on December 22, 2007

The local government at my last place changed all the lights in my house over to CFL a few months back. No delays, no flickering, good color. No complaints from me! I think they were mostly Phillips.
posted by the duck by the oboe at 8:58 AM on December 22, 2007

That points out another negative to CF bulbs: some suck. Not all, not most, but some. The crummy ones get bought and then thrown away or put in a closet, and replaced with another one. The lengthened lifetime is meaningless, because it's not even used. No one ever does that with incandescent bulbs.
posted by smackfu at 9:04 AM on December 22, 2007

In my own personal experience, my lighting fixture covers are hard to remove/replace and I have broken one doing so. When I used regular bulbs, I was changing them once every two months. Now I probably change them once a year, or less (in fact I think it's more like once every 1.5 years). So for me, I never have to buy bulbs, my chances of hurting myself and breaking my fixtures is decreased, and with vaulted ceilings, I have fewer trips up and down the ladder, which lessens my chances of personal injury. For me, all those factors combined made this a win. Direct light from them is kinda harsh, I agree; I don't use them in my reading lamps or in my kitchen/dining area for that very reason.

There are instructions on how to dispose of the bulbs to decrease the impact of the mercury; I'm pretty sure you can take them to certain recycling centers or home improvement stores for safe disposal.
posted by Unicorn on the cob at 9:18 AM on December 22, 2007

You are confused over the 15 minutes. CF bulbs do not have a significant start up energy use, maybe 15 seconds. They just use that figure as for some bulbs, like the one in your dryer, or closet, which is one for but a few minutes at a time every now and then, you probably will not recover the added expense of a CF. I like CF in closets with shelves for a different reason. If someone piles clothes too close to the bulb it won't start a fire.

As for color, incandescent bulbs have a fairly broad spectrum emission with a heavy yellow emphasis. Halogens, my favorites for lighting quality, have a broad spectrum emission close to natural light. CF bulbs have a narrow emission spectrum. You can select the warmth or coolness, but it is not entirely natural as the spectrum is limited. (all this from memory so I may have some of it wrong). I typically use the n vision bulbs from home depot (red for the living areas, green for others). There are better bulbs available I think, but I am a little tight that way.
posted by caddis at 9:23 AM on December 22, 2007

Three way CF
Dimmable CF
Availability: Currently unavailable. We don't know when or if this item will be back in stock.
Maybe next year...

I'm switching to CF bulbs as the old incandescents burn out.
posted by Robert Angelo at 9:38 AM on December 22, 2007

I'll address your four concerns individually:

1) Mercury.

Links above shows that, at least in the USA, incandescent bulbs cause greater mercury emissions.

2) Leaving the bulb on for 15 minutes.

I think you are misreading Energy Star. They aren't telling you that you must leave the bulb on for 15 minutes. They are saying that, at the minimum, you should use a CFL wherever you leave the light on for more than 15 minutes at a time. All they mean is that the energy savings if you switch to a CFL that you only turn on a couple times a day for 30 seconds isn't going to be very significant.

3) Manufacturing energy costs.

I couldn't find any solid information on this, but one can make a useful approximation from the purchase cost. I'd say incandescent bulbs cost $0.25 each and CFLs cost $2.50 (based on purchase of 4-pack of either). We can be pretty confident that no more than the dollar cost of the bulb worth of energy is used in the manufacture of the bulb. So we know that the energy used to manufacture a CFL is probably not more than 10 times the energy used to manufacture a incandescent bulb. Likely, it's less because a CFL is more complicated, has more parts, etc. so it takes relatively more engineering, more machinery, etc. than the simple incandescent bulb and probably has a lower proportion of energy cost reflected in its total cost. In any case, Wikipedia says that CFLs last 8 to 15 times longer than incandescent bulbs, so the energy cost for manufacturing, per hour of lighting is likely, at worst, roughly the same.

4) Heating and cooling costs.

During the heating season, the net energy cost depends on your heating method. If you heat with electricity, then your bulb choice won't make any difference: all the "wasted" energy from the incandescent bulb is used to heat your house, just as your heater would. If you heat with gas, you'll use more energy heating with the incandescent bulb than with your furnace because the production and transmission of electricity is less efficient than your gas furnace (if you have a very high efficiency gas furnace and live in a part of the USA with a lot of renewable energy electricity generation, this might not be true, but on average in the USA, it is). So, worst case scenario: zero energy savings from CFLs.

During the cooling season, the extra heat produced by incandescent bulbs not only costs you extra energy to produce, it also costs more energy again to remove it from your home.

If you aren't heating or cooling, the incandescent obviously cost more energy to run.

Overall, the energy cost for the incandescent bulb is greater than the CFL over the year. You might not save quite as much energy as commonly bandied around figures claim, but it'll be fairly close (for example, if you heat a third of the year with electricity and cool a third of the year with a high efficiency air conditioner, you'll only save about 75% of the claimed amount of power because your air conditioner is more efficient at removing heat than your heater is at producing it).

In the end, switching to CFLs is still the environmentally (and economically) smart thing to do.
posted by ssg at 9:50 AM on December 22, 2007

Oops, in 4) that should obviously read "(if you have a very low efficiency gas furnace and live in a part of the USA with a lot of renewable energy electricity generation, this might not be true, but on average in the USA, it is)"
posted by ssg at 9:53 AM on December 22, 2007

Popular Mechanics reviewed a whole bunch of CFLs in May 2007.

Here it is.

They liked pretty much all of them better than the typical incandescent. I think you guys are buying crappy, crappy bulbs. Don't buy your CFLs from Walmart or the supermarket.

I generally use the MaxLite MicroMax and am very happy with how it renders colors. A "60 watt equivalent" (15w)MaxLite appears slightly dimmer than a 60w incandescent, so sometimes I'll use a 75 watt equivalent (20w) depending on where the bulb goes.
posted by Justinian at 10:33 AM on December 22, 2007 [2 favorites]

If you switch to good quality CFs now, by the time you burn them out there will most likely be economical warm-light LED bulbs around. You can get them already for Christmas tree lights, nightlights, etc. They contain no mercury, will last 100,000 hours compared with CFs at 10,000 and incandescents at 1000, and are even more efficient than CFs. Once this happens, your lightbulbs will outlive you. If you want to try them now, here you go.
posted by beagle at 11:16 AM on December 22, 2007

Oh, and no flicker or warmup, either.
posted by beagle at 11:18 AM on December 22, 2007

I converted about 4 years ago when I first saw them at Costco. They always turn on instantly, without flicker, and the colour is wonderful. I have Philips.

Of course, I haven't had to change one in years as well.
posted by juiceCake at 11:32 AM on December 22, 2007

I have a few concerns about these, but only one is environmental. There have been some mentions of CFLs being recyclable, maybe, in some places. Who here has actually recycled their CFLs, and how easy was it?

Throwing them into a landfill is going to cause major problems, to my mind.

(My other problem is that CFLs seem to trigger migraines in migraine sufferers, and seizures in epileptics--something to do with the flicker rate. If anyone can speak informatively about this, I'm interested.)
posted by Riverine at 11:33 AM on December 22, 2007

Enter "cfl" and your zip code here for recycling options. via 5 Ways to Recycle a CFL

I haven't had a CFL burn out yet, but I have recycled other household hazardous waste through our city's program. It was pretty easy, and they gave me a couple of CFLs for my trouble.
posted by hydrophonic at 11:56 AM on December 22, 2007 [1 favorite]

(My other problem is that CFLs seem to trigger migraines in migraine sufferers, and seizures in epileptics--something to do with the flicker rate. If anyone can speak informatively about this, I'm interested.)

Okay, I can. Unless you are buying those aforementioned bargain basement crappy ones with a magnetic ballast, your CFL will have an electronic ballast and won't flicker.

It's pretty easy. Magnetic ballast = flicker. Electronic ballast = no flicker.
posted by Justinian at 12:08 PM on December 22, 2007

Regarding energy of manufacture, CFL comes out ahead. You can tell because the money you save on power dwarfs the extra cost of the bulb, and the energy of manufacture is included in the price of the bulb. Even in areas where manufacturers pay less for energy than you, or are otherwise subsidised, the difference in the numbers seems to me to be too much to make a realistic argument.

What bothers me, is that these energy savings don't appear to save energy, they just raise your standard of living by making your dollars go further. Money that you save on power bills doesn't go to the environment, it's still in your wallet, so you spend it on additional consuming that you otherwise would not have been able to afford. Additional consuming means you are using additional energy (energy of manufacture, mining, etc). Thus your net energy use does not fall unless you use the money on things that cost more for the same thing, only a greener version of it.

In this case, that means if your energy supplier has a green power option (you pay more per kW, in exchange for the supplier agreeing to purchase that amount more power from green energy generation), then you should go CFL, and spend the money you save on more expensive (but non-coal) energy generation.

Net savings to you: Zero. But now you're actually maybe achieving something.
posted by -harlequin- at 1:38 PM on December 22, 2007

wackybrit writes "I don't know if the US has particularly poor CFLs compared to Europe, but the CFLs we have are 'warmer' (light wise), I'd say, than regular bulbs. Certainly more amber / orange in their glow whereas regular bulbs tend closer to pure white.. and we just use the cheapest energy saving bulbs we can find"

Quality varies alot in Canada. I find that places with no hassle returns (EG: Costco) carry a decent performing light. The only thing I've had trouble buying is a round globe bulb for use in unshaded fixtures in bathrooms. I can't seem to find one that doesn't take a minute or two to warm up. I've surmised they are slow to light up as a trade off for better colour rendition.

odinsdream writes "I'm still waiting for CF's capable of being dimmed or used in three-way fixtures. "

Home depot has 3-way CFLs in two different wattage ranges. Bought two last week.

smackfu writes "The crummy ones get bought and then thrown away or put in a closet, and replaced with another one. The lengthened lifetime is meaningless, because it's not even used. No one ever does that with incandescent bulbs."

I've disposed of (well given away rather than throwing away) many incandescent bulbs. Seems every place I've ever moved into had a stash of incandescents of the bare filament no frosting style which are instant headache inducing for me.

The Hg thing is a bit over blown IMO. Not that we shouldn't dispose of and treat the bulbs carefully but even a can of tuna can run as high as 1 ppm of mercury. Six cans can contain .1 mg of Hg.
posted by Mitheral at 1:53 PM on December 22, 2007

Wow....I've been converting our incandescents to CF's for years. Many of them are hated by my wife, and since some are in a storage area, I went back to incandescent. They're on for a very short period.

I found the BEST CF's at the Dollarama (a dollar store chain in Canada). They are the Sylvania brand...they last long, start quickly, and don't flicker.

Regarding colour of these bulbs: There seem to be two "models" of these Sylvania bulbs. The only way you can tell is to look at the base of bulb through the plastic packaging.

The difference is important, and it relates to the colour temperature. The ones that are 6200 (or 6400) K are harsh and white...not fit for human consumption, but good for plant lights. These are in the blue-white harsh spectrum.

The 2700K (K is for Kelvin...I should be writing 2700 degrees Kelvin) bulbs are a warm white. Quite OK for humans.

The only other downside is that these bulbs are not in a coil, but are the shape of a stretched U.

I've used other CF bulbs and they had varying life, and as they die they exhibit strange behaviour. Flip the switch (they do not like to be in pull-chain fixtures...maybe the vibration gets to them) and they don't go on. Touch them ever so lightly (they are well screwed in) and they illuminate. Weird.

I saw some dimmable ones in a local store and my opinion is to forget it.
posted by mbarryf at 2:40 PM on December 22, 2007

Just an FYI on recycling the CFLs, Ikea (at least the one in Seattle) takes used CFLs.
posted by mge at 7:23 PM on December 22, 2007

Definitely DO NOT put cf bulbs into recessed lights. We replaced the recessed canister lights on a ceiling fan with cf bulbs and were startled one evening by a loud popping sound, which accompanied smoke. Fortunately we were home, when I pulled the bulb out it was hot and smoking. I feel like it could have been a fire hazard in addition to a toxic smoke hazard for the people and animals in my house.

I feel like more information about recycling and safety is needed for consumers of CF lightbulbs. I am concerned about how entire populations pitching their CFs into their trash is going to affect ground water in 15-20 years.
posted by pluckysparrow at 9:34 PM on December 22, 2007

Can somebody explain to me why you 'd need a special CF bulb just to make it work three-way? Is this a US thing I'm just not understanding from my position in the Southern Hemisphere?

Where I live, "three-way" just means that you can turn the same lamp on and off from two different switches. The way it's implemented is like this:
                *--------*               /active -------*  A      B  *-----------+                          /            |                *--------*             |                                      bulb                                       |                                       |neutral -------------------------------+
If switch A is up and B is down (as shown), or B is up and A is down, there is no current path and the bulb is off; if A and B are both up or down, then there is a current path and the bulb is on. From the bulb's point of view, there is either power applied or not, same as for a single switch. So why would a special kind of lamp be called for?
posted by flabdablet at 10:48 PM on December 22, 2007

Three-way means that there are three different settings of power. Low, medium and high. Intrinsic to the lamp, and not to the wiring around said lamp.
CFs are either on or they're not. Defeats the whole benefit of the three-way light.
posted by lilithim at 11:52 PM on December 22, 2007

The overhead light fixture in my kitchen has three sockets. Three years ago, I replaced two of the bulbs with CFs and left in one incandescent bulb. Since then, I've replaced the incandescent bulb once. I've replaced one CF twice and the other three times. I've had similarly crappy lifespan results with CFs in other lamps, to the point where I write the "put into service" date on the CFs base because I thought I was losing my mind and wanted to verify the fast die-offs. None have lasted longer than 6 months; I've tried myriad brands. WTF am I doing wrong?

Oh, and I hate the color of CF lighting. I'm so stockpiling incandescent bulbs.
posted by jamaro at 12:18 AM on December 23, 2007

Thanks, lilithim. I've never seen that style of lamp in Australia.

Curious, though: if the light level depends only on the lamp, how do you pick which level you want?
posted by flabdablet at 12:33 AM on December 23, 2007

I am a big fan of CFLs and use them more and more as styles compatible with different fixtures come out. However, CFLs are already on the way out, as LEDs become practical with even more benefits. The three types of lighting are compared here.
posted by TedW at 2:59 AM on December 23, 2007

I'm more than a bit late coming into the discussion, but I'd just like to point out that it's not really fair to lump mercury and energy consumption (which translates to CO2 production, unless all your energy comes from renewables or nuclear) into one big issue of **SAVING THE ENVIRONMENT**. If I had to choose between putting extra mercury in the environment and extra CO2, I would go with the mercury. There is no looming global crisis being caused by Mercury. There is for CO2.

And for the record, I'm pretty happy with the light quality of my CFLs, and they're Phillips and GE.
posted by gueneverey at 9:07 AM on December 23, 2007

if the light level depends only on the lamp, how do you pick which level you want?

There are two separate filaments in a three-way bulb, one brighter than the other. The three levels are: dim filament on, bright filament on, and both filaments on. A normal lamp socket has a contact and the socket, while a three-way socket has two contacts in addition to the screw socket. Then the lamp has a special switch that routes the current across the contacts in an intuitive way.
posted by smackfu at 10:57 AM on December 23, 2007

jamaro writes "WTF am I doing wrong?"

CFL are often sensitive to mounting direction. If your fixture holds the bulb with the screw base up make sure you are using a CFL rated for base up use. Most are designed for base down use and will tolerate sideways mounting but quickly burn up when mounted base up.
posted by Mitheral at 2:47 PM on December 23, 2007

Thanks, smackfu. I have never seen anything like that in this country, except perhaps car headlamps that have separate high beam and low beam filaments (and even those are not designed to run both filaments at once).

jamaro, it sounds like your light fitting doesn't ventilate well, thereby causing the electronics in your CFL to operate at continuously high temperatures. Maybe you could drill a few discreet holes in it.

I also write the installation dates on the bases of my CFL's. I've had one fail at six months, but most of them manage about four years. Most of them are Mirabella (probably not available under that brand in the US).
posted by flabdablet at 4:52 PM on December 23, 2007

Mitheral, you're a genius: the CFL-eating fixtures I mentioned all hold the bulbs sideways or upside-down. I had no idea it made a difference. Thank you!
posted by jamaro at 10:38 AM on December 24, 2007

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