Cold Cathode Fluorescent Lamps (CCFLs) have been around for about five years, but don't get the consideration they often deserve. They have more than double the life of standard Compact Fluorescent Lamps (CFLs) and are better incandescent bulb replacements for dimming and flashing applications.
A quick technical overview
CCFL and CFL technologies are very similar - they both use integrated ballasts to regulate electrical current into a glass tube to excite mercury and phosphors and make UV light. The biggest differences between the two technologies are the type, temp, and resiliency of the cathodes used at the ends of the glass tubes. Standard CFL cathodes incorporate a thin tungsten wire that gets to 900°F while CCFL cathodes are more like solid metal thimbles that peak around 200°F (a "cold" cathode, relatively speaking.) Because the CCFL cathodes are more durable, they can be hit with more voltage (about 5 X) more often than standard CFLs and that opens up opportunities to use CCFL in applications where CFL products consistently fail.
Benefits and Applications
As a result of the increased voltage required to start the bulb, CCFL products can be flashed on and off rapidly and repeatedly. This is great for theatre marquees, message boards, and warning sign applications. Though not with the same speed or frequency, bathroom and some hallway lights experience many on/off cycles throughout a given day making CCFL bulbs a great choice and value. And while dimmer/bulb compatibility issues can still exist, the larger size of the CCFL cathode enables improved dimming capability often down to 5% of their total light output. Traditional CFLs can usually only be dimmed to only about 20%.
Cathode durability gives CCFL bulbs a big advantage in replacement cost savings. A much longer average rated life (typically 18,000-25,000 hours) than traditional CFLs (8,000-10,000) requires fewer bulb changes and results in lower maintenance time and money.
Use with timers, photo sensors, and motion sensors remains problematic for both CCFL and CFL technologies. Those technologies don't provide a hard on/off cycle and leave a "voltage trickle" even in the off position that continuously feeds electricity to the ballast, killing it prematurely.
CCFL bulb choices are still limited when replacing incandescent bulbs greater than 75 watts and traditional CFLs are a better choice when more lumens are required. Additionally, cold cathode bulbs are typically more expensive than CFLs in applications where either technology would do the job.
If you're looking to save energy and maintenance costs on an application with a dimmer or lots of on/off cycles, CCFL is a proven cost-effective option to consider.