Another black eye for CFLs

Lifetimes shorter than advertised.
Slow (minutes-long) start up times.
Environment-contaminating mercury.

Now add power consumption to the list of reasons why compact fluorescent lamps (CFLs) aren't all they cracked up to be.

This EDN article points out that CFLs have a terrible power factor, between 0.4 and 0.6. In layman's terms, this means the lamps are using 66 to 150% more energy than advertised: a 13 watt lamp may require the power company to actually pump the energy equivalent of 32.5 watts down the line to light it up.

The good news -- for you, at least -- is that you're not actually billed this larger amount. Electric meters measure "real power" -- the 13 watts put off by the bulb. The bad news -- for the utilities and the environment -- is that the electric company has to provide the "apparent power", or the equivalent of 32.5 watts.

This is still less than the 60 watts needed for an incandescent bulb, but it does eat away at the magic of CFLs.

(Apparent power is usually given in volt-amperes; this is dimensionally equivalent to a watt, but this helps us electrical geeks to distinguish when we're talking about "real" vs. "apparent" power.)