Was helping a friend with some lighting. He bought some “dimmable” compact flour. bulbs.
Is there a special dimmer for these?
The dimmer he bought says use for incand. and halogen bulbs. Do the dimmable CFLs act like these or does he need a special dimmer for this.
The HD staff is useless as usual.
I wired it up and it seems to work, but the CFLs are pretty expensive and I don’t want to burn them out prematurely.
Thanks.
Replies
The following is from the Environmental Defense Fund. It doesn't specifically mention whether there are types of dimmers that won't work with dimmable CFLs, but I am guessing that since they don't mention it, they are assuming that either the electronic or the rheostat type dimmers will work.
from: http://www.edf.org/page.cfm?tagid=631
Dimmable Compact Fluorescent Lights
When it comes to dimming, compact fluorescents work differently from their incandescent cousins. In order for a CF bulb to work in a dimmer, it must be specially designed to do so. Be sure to read the package so that you'll know if your CF bulb works in dimmer-controlled fixtures. Also, finding where to buy dimmable CFs can be particularly difficult, but don't get discouraged. Start with our list of dimmable CF bulbs.
Here's another quirk. Unfortunately, even if a CF is designed for dimmers it might not work in yours. (The CF packaging spells this out, as well.) Sometimes the only way to be sure a bulb will work is to test it. Check the store’s return policy and keep your receipt -- or let a friend try the energy-saving bulb. But know that there's a bit of trial-and-error involved in the process.
One last caveat. Once you've screwed your dimmable CF into your fixture and begin test-driving it, you might notice a difference in its dimming range. While incandescent bulbs dim smoothly between being completely off to 100 percent brightness, CF bulbs have a narrower dimming range. Generally, dimmable CF bulbs can dim between 20 and 90 percent of full light.
Why CF bulbs are harder to dim than traditional bulbs
You can dim a traditional incandescent bulb simply by reducing the amount of power sent to the bulb. Less power means less heat and less light.
With CF bulbs, dimming is more complicated. Reducing power to a CF bulb can keep its filament from getting hot enough to work properly, and the bulb simply goes out. Reducing the voltage can dim the light only by 30 to 50 percent. To achieve better, more consistent dimming, designers must make other adjustments.
In all fluorescent bulbs, the ballasts (the bulb's "engine" located inside the ceramic between the socket and bulb) are what make them work. The ballast both starts the light and keeps it lit.
Early CF bulbs had magnetic ballasts that did not easily lend themselves to dimming. When electronic ballasts came on the scene, it was easier to design these CFs for dimming. However, as with any new technology, dimmable CF bulbs are still being refined. As more companies enter the growing market for energy-saving bulbs, the options for dimmable bulbs are expected to become wider and more easily available.
It is worth the effort to find a CF for your dimmerâ€â€dimmable CF bulbs are hands-down more efficient than traditional incandescent bulbs. They use less electricity, cause less pollution and last much longer. Plus, when you dim a CF bulb, you save even more electricity.
Posted: 12-Oct-2006; Updated: 01-Aug-2007
I know one thing, the new T-8 4' flourescent bulbs with the electronic ballasts are noisy as hell. Replaced all 7 8' T-12 magnetic ballast fixtures in my shop with dual 4' T-8's and now my radio sounds like somebody is frying bacon on my favorite station...
Maybe the ballasts are crappy, they shouldn't be emitting that much RF. Are they uncased? Check the grounds on them as well... Though I don't know what else might be affected in your house wiring by the RF. Some interesting suggestions here:
http://brneurosci.org/fluorescent-lamp-interference.htmlZ
They're good old 100% Chinese HD shop lights. All grounded. Thanks for the link. I'll check it out.
Have you checked the ground inside the fixture though? I just replaced a ballast in my HD specials as well and it wasn't grounded inside the fixture at all.Z
You don't need a special dimmer, though the dimming behavior you get may not be particularly acceptable to you. You just have to try it and see.
I changed out the incandescents for dimmable CF's where I could in my house, left the standard off the shelf wall dimmers in place. Worked fine for me. There is sometimes a burn in period where the bulb will flicker a bit when dimmed down, but it soon passes.
So far so good. The dimmer seems to work but I do notice the dimmer needs to slide up further than I would have thought before the light comes on. It does dim and my friend seems happy with it so I guess "my work here is done".
Thanks.