Originally Posted by Neurorad
FWIW, fluorescents are dimmable, but require a third wire, and a dimmable ballast. I have one in my workshop, near the TV. Dims to about 30%, I estimate.
Let me just clarify a bit by saying most 4pin plug in and 2ft & over linear fluorescent are dimmable, assuming you have the appropriate dimming ballast and dimmer. There are at least 3 types of commonly used dimmable ballast types 0-10v, 3-Wire (as mentioned by Neurorad), & tu-wire. Each has a specific type of dimmer associated with it. There are also some more exotic ones.
Some screw in "CFL" (if labeled dimmable) will dim OK, and that's what the RRD-6CL is intended for (as well as LED screw in lamps, recessed and retro LED)
Aside from the RRD-6CL, currently RR2 only addresses 3-wire (via RRD-F6AN) & the 0-10v (0-10v module may be Inclusive only??)
So yes, most current fluorescent lamps using a separate ballast could be converted to dimming. However, self ballasted lamps may or may not be (most aren't).
Laslty, if you are dimming fluorescent lamps you should be "seasoning" or burning them in. They recommend you run the lamps initially and anytime you re-lamps at 100% for the first 100hrs. This will extend you lamp life and they will dim better, longer...