Dimmable CFL

[Tony Hwang]

Hi, Came across a 23W dimmable CFL. Got one to try it out. It worked ~2 hours and pop, it went to full brightness and no more dimmable??!! Are they this unreliable? Or I got bad one.

[Don Klipstein]

Please tell us the details!

The usual "dimmable CFL" to most looking for those means one that is safely usable with a "usual light dimmer". I find it hard to believe a lamp refusing completely to be dimmed by a usual-for-incandescent-type dimmer. Non-dimmable lamps tend to have short life expectancy when used with a dimmer against their instructions, and may blow the dimmer. Usually the lamp is what dies.

- Don Klipstein ( [e-mail])

[Tony Hwang]

Hi, Packaging clearly said it is dimmable. I screwed it in side by side with

60W incdescent lamp, dimmed up and down a few times and noticed when dimmed too low it was scintillating. At certain point it quit doing that where I left it. Soon it went to full brightness while the other lamp was still dimmed. From then on it is no more dimming, just stay at full bightness.

[Art Todesco]

I don't believe that it should be expected to pop. I have 2 of them. They don't dim very well. By that I mean, when dimmed, they flicker quite a bit. The range is good if you can stand the blinkety blink. There are spots where they seem to settle down and be ok. BTW, I am using this on an X10 lamp module, so finding a "good" spot is quite difficult. With a real dimmer, it might be easier.

["Blattus Slaf]

You can't really expect a CFL to have the same range as an incandescent bulb. If you are testing it to extremes you can expect it to pop.

[ransley]

Take it back, im sure it has a warranty, but I dought cfls dim well, they probably go red in color dimmed

[Pete C.]

I expect you got a dud. The dimmable CFL I experimented with seemed to work fine. It also performed a lot better after a day of full on burn in period which I presume helped get all the mercury vaporized and the phosphors settled.

[Don Klipstein]

I suspect the ballast circuitry in the CFL had part of it fail, and the CFL converted itself into a conventional CFL. Those can have hardly any dimming and can appear to be at full brightness until the dimmer is dimmed past the point at which an incandescent has about 1/4 its normal brightness. They can also be hard on the dimmer.

CFLs also often dim more slowly than incandescents do at first, being about half brightness (or more) at a point at which an incandescent is about 1/4 brightness. A CFL may start dimming more rapidly when dimmed almost to being off, or may just suddenly turn off.

Special dimming ballasts for ballastless CFLs do better.

- Don Klipstein ( [e-mail])

[Don Klipstein]

I have this sinking feeling that dimmable screw-base CFLs at least sometimes lack provision to have their filaments maintained at a proper temperature when they are dimmed. I would expect some compromise in life expectancy with severe or moderately severe dimming.

One scheme mentioned a lot in some thread in sci.engr.lighting earlier this year is to have two sets of lights in a room - one for bright lighting and another for dim lighting.

- Don Klipstein ( [e-mail])

[Don Klipstein]

I have done enough CFL dimming to know that indoor ones used indoors do not change color much from dimming. I have seen some get slightly warmer or slightly cooler in color from change in current and change in temperature, but that's it.

One complaint of dimming fluorescents is lack of the color getting warmer as the lamps are dimmed. The lighting can take on a "dreary gray" appearance with severe dimming as a result.

- Don Klipstein ( [e-mail])

[Pete C.]

Back to the old style 3-way lighting from before they made multi filament lamps and used several individual lamps instead. Put three small normal CFLs in that type of fixture and you're all set.

[Wayne Boatwright]

On Sun 27 Apr 2008 12:42:38p, Pete C. told us...

Hmm... Yes, like the old floor lamps that had 3 standard base sockets and one central mogul base socket. I wish I still had one of the really nice ones that my parents had. It was a beautiful lamp with marble base and engraved bronze post. An adapter could be put in the mogul base in order to use a CFL there, too.

We have several true antique tiffany-style glass and craftsman style lamps with mica shades that have either 2 or 3 pull chain sockets in them. However, I still use clear incandescent bulbs in them because the CFLs make them look extremely dull. I have thumbwheel dimmers on the line cords and I use slightly higher wattage bulbs than one might want so that when dimmed they give a much warmer light.

[Frank]

I have replaced 8 can lights with 16 watt dimmable bulbs and they are great been in use about 1yr. I also replaced same situation lamps over my bar but on same circuit as flame type lamps on same dimmer. CFL lasted 2min. Seems like the CFL lamp is killed by voltage noise or disruption. Not going to plug CFL mfg unless asked. Frank

[Wayne Boatwright]

On Sun 27 Apr 2008 02:50:37p, Frank told us...

I think the problem is mixing incandescents of any type along with CFLs on the same dimmer.

[Pete C.]

They have big honkin' CFLs with mogul bases too. They're starting to appear at the big boxes. You have to be careful though because there are also some similar looking mogul based CFLs that are designed to directly replace HID lights such as mercury vapor without removing the HID ballast.

Have you tried looking for a CFL with a warmer (lower) color temperature? Also if you try them be sure to try them for a few days since your eyes will adjust.

[Wayne Boatwright]

On Sun 27 Apr 2008 06:41:34p, Pete C. told us...

Thanks, Pete, didn't know that. Unfortunately, I no longer have any of the floor lamps I could have used one in.

It's not just the color (warmth) of the light that's an issue. It's the transparency of an clear incandescent and the filiment showing through that causes the glass shades to glisten. I doubt there will ever be a CFL that can produce that effect.

At least the upcoming ban on many incandescent bulbs will not include decorative bulbs like the very old style of swirled flame bulb. At least that's my understanding.

Another option I've used in very old lighting with two bulbs is wiring them in series. The bulbs last forever and the color and intensity is just right. I have one fixture that remains on constantly, that the bulbs are probably 30 years old or older.

As an aside, it's been said that Edison's home in Florida that is wired with DC power still has the working original bulbs throughout.

[Don Klipstein]

CAUTION - most of those mogul screw base ballastless CFLs get overpowered in HID fixtures - should they work at all.

CFLs of wattage over 50 watts (and for that matter also most under

50 watts) tend to either have their own internal ballasts or require ballasts specific to themselves as opposed to ballasts for mercury or other HID lamps. Do not put a mogul base CFL into a 175 watt mercury fixture unless it is rated for use in a 175 watt mercury fixture and also has the ANSI "ballast compatibility" code of H39. Other HID "retrofit lamps" have other ANSI "ballast compatibility" codes on either the bulb or the package or in any inserted printed material. Use those in HID fixtures only if the fixture and/or the ballast has an ANSI "ballast compatibility" code same as one for the lamp (lightbulb). Otherwise, there is probability or possibility of malfunction, including significant chance that malfunction will occur "down the road" should the lamp work "apparently OK" initially. Such malfunctions may include hazardous ones.

Keep in mind that there is such a thing as ballastless mogul screw base CFLs that lack any ANSI "ballast compatibility" codes. Those require ballasts/fixtures recommended by the lamp manufacturer, which may be proprietary ones. The best example that I can think of is Lights of America "Fluorex" lamps, widely available at Home Depot.

- Don Klipstein ( [e-mail])

[Don Klipstein]

In article , Wayne Boatwright wrote in part:

Just keep in mind that such century-life incandescents have energy efficiency so low that in order to produce a given amount of light, you increase your electric bill more than you decrease your lightbulb replacement costs.

The first-mass-marketed carbon filament incandescents had energy efficiency of a couple to at most a few lumens per watt.

There is a "centennial bulb" with a webcam showing a publicly accessable view of it continuing to work. I give low odds of its energy efficiency exceeding that of a 230 volt incandescent being powered by 120 volts, or roughly 1/4-1/3 that of modern 60-100 watt 750-1000 hour incandescents.

- Don Klipstein ( [e-mail])

[Art Todesco]

They really don't have filaments as regular fluorescent lamps. Because they use an electronic ballast, the voltage can be high enough to not need the traditional heated filament, starter, etc.

[Wayne Boatwright]

On Sun 27 Apr 2008 08:32:16p, Don Klipstein told us...

I've no doubt of the inefficiency, but thought it was interesting, and I've seen the Centennial Bulb before. Just thought it was a curiosity.

As a further aside, my dad had a habit of installing double light fixtures with 25 watt bulbs at strategic places throughout the house and basement, wired in series, to produce a very low light level. He didn't like walking into dark rooms, especially when the light switch wasn't near the entry. To him, of course, this wasn't a waste of energy. Of course, this was in an era when energy consumption was not an issue or concern.