In our house we have migrated from incandescent to CFLs, and now partly to LEDs. I was curious to verify if the power consumption of these newer light bulbs was really as good as advertised. I borrowed a Kill A Watt meter from our local electric company (SRP) through the library. I measured a variety of different bulbs in a regular lamp (non-dimmable). Here are the results:
I was pleasantly surprised to see all of the measurements were less than the advertised wattage. It was also interesting to see that CFLs have the lowest power factor, and on average the LED bulbs had a better power factor. As expected the incandescent have the best, as they're pretty much just a resistor. Our electric company meters Watt-Hours, and bills us by the same, so the lower power factor numbers don't really matter to my electric bill.
LED versus CFL:
LEDs have recently come down in price so they are more cost effective. I've started only buying LEDs for replacements instead of CFLs. We never had great luck with CFLs. My biggest complaint was that they didn't last nearly as long as advertised on the package. The other problem with CFLs is their turn-on delay, and warm-up time. Lastly the fact that they contain mercury isn't attractive. The LEDs I've purchased so far have a much better turn-on time, and don't require time to warm up to their full brightness like CFLs do. They also do not contain any mercury. The jury is still out on their longevity, but I'm hopeful they will perform better here too.