“CFL” is a household name at this point. Developed in 1985, the compact fluorescent light bulb is now a 25-year-old product present in 70 percent of homes in the United States. Just last year, more than 273 million CFLs were sold in the U.S.
Cold cathode fluorescent light bulbs are a little less familiar, at least to the general public. Here’s a quick overview of the core differences.
All fluorescent light bulbs have two cathodes (one at each end). In a standard CFL, the cathodes are made of coiled tungsten filaments that are heated to approximately 900 degrees Fahrenheit each time the light bulb is turned on. That heat releases electrons. The electrons shoot back and forth between the cathodes and react with the mercury to create ultraviolet radiation, which in turn reacts with the phosphor coating on the inside of the glass envelope to create light. Standard CFLs are hot cathode light bulbs.
In a cold cathode fluorescent light bulb, the cathodes are made of a solid metal thimble, which is more durable than the thin coils in standard CFLs. The cathodes only heat up to about 200 degrees Fahrenheit (certainly not “cold”, but relatively cooler than the hot cathode filament, hence the name). The voltage potential within the tube excites the mercury to cause current flow.
- CFLs have limited dimming capabilities.
- CCFLs are dimmable down to 5% of light output, making them similar to incandescent light bulbs.
Reducing the voltage to a hot cathode fluorescent ballast in turn reduces the temperature of the cathodes. CFLs require cathodes to be hot enough to emit electrons in order to excite the mercury atoms.
The cathodes on CCFLs do not need to be heated as much to operate (see technological differences). Also, the solid metal thimble in a CCFL can withstand dimming better than the thin coil filament in a CFL.
- CFLs, when used in flashing signs, experience a significant decrease in average rated life.
- CCFLs are ideal for flashing signs.
The solid metal thimble inside a cold cathode fluorescent light bulb can withstand shock and vibration better than the tungsten filament inside a hot cathode fluorescent light bulb.
- Up to 15,000 hours in a CFL
- Up to 25,000 hours in a CCFL
CCFLs have a longer average lifetime from the start, equivalent with some LEDs. In addition, due to more durable cathodes, CCFLs are rarely affected by different modes of operation, such as rapid on-off cycles. The lifetime of a CFL, in contrast, is significantly shortened (up to 85%) if it is consistently only turned on for a few minutes at a time.
- When CFLs are first switched on, they typically only provide 50-80% of their potential light output, and may take up to three minutes to achieve full brightness.
- CCFLs turn on instantly to full light output.
Because the cathodes in CFLs must heat up to 900 degrees, there is a lag in start time, which is exacerbated by cold weather.
9 thoughts to “CCFL vs. CFL: What’s the Difference?”
excellent article clarifying the significant difference between
CCFL and CFL. great work – capturing the major technical difference between these two technologies in generally understandable terms.
I saw from the CFL wikipedia article that CCFL bulbs are about half the energy efficiency of CFL bulbs. As in, say a 10 watt CFL bulb puts out a certain amount of lumens, then to get the same lumens from a CCFL bulb, it would take about 20 watts. Is this true? If so, CCFLs may be far from being as efficient as LED lighting.
CCFLs last up to four times as long as CFLs. The typical lifetime is about 25,000 hours, which is equivalent to many LED lamps. That means you’re purchasing fewer replacement bulbs.
I am not sure where that stat came from in the Wikipedia article – I just looked at it as well, and it says “citation needed.”
I can tell you that we offer A19 lamp CCFLs (that’s the standard light bulb size that will screw-in to your floor or table lamp) that consume 8 watts and are comparable in light output to a 40W incandescent. A19 lamp CFLs that are comparable in light output to a 40W incandescent typically consume about 9 watts.
Was wondering, if CCFL are equally (if not more) energy efficient than CFL and have a longer life-span, then why is it not perceived as a threat to the CFL industry and why has CCFL not really taken off? From what I gather, the manufacturing costs in CCFL are equivalent to CFL!!
I think it’s safe to assume that for the most part, the CFL industry is the same as the CCFL industry. The lamps themselves are very similar, and many manufacturers that make CFLs also make CCFLs. As far as why CCFLs haven’t really taken off, I think that’s because they’re just not very well-known (to the general public, at least)!
Currently connected with Enchanted Kingdom Inc. (local theme park). Quite very interesting, do you have local distributors here in the Philippines?
Joseph, we sell lighting exclusively on our website, http://www.PegasusLighting.com. If you’re looking for CCFLs, check here. We also offer large quantity discounts – call our customer service line at 800-392-4818 if you have any questions.
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