I just tested two CFL's on my Kill-A-Watt meter. A new inexpensive one (about $1.00) was rated 11 watts, 200 ma, 120 volts. Another about 10 years old (probably about $10.00) was rated 20 watts, 185 ma, 120 volts. The meter reported the following:
House volts = 122
New CFL: 12 watts, 23 va, 0.19 amps, pf = .53
Old CFL: 16 watts, 18 va, 0.15 amps, pf = .89
The new CFL appears to be much less efficient than the old CFL. Also, the new CFL is using 23 watts/equivalent of power if compared to an incandescent bulb. CFL's are rated at 44-80 lumens/watt, and incandescent are rated at 7-24 lumens/watt. While it appears that the new CFL is producing more lumens/watt than an incandescent bulb, it is not nearly as efficient as I would have assumed, and particularly as compared to the old CFL.
While the lack of efficiency does not translate to watts used, and therefore does not directly impact my electric bill, it seems to me that there should be an understandable standard manufacturers of CFL's, perhaps all lighting bulbs, should be required to label so that a retail customer can easily know the efficiency of various CFL's. Perhaps lumens/va rather than lumens/watt. Although most retail customers probably don't really know what a watt is, they certainly don't know what volt-amps are. So maybe an energy standard of lumens/power unit, or something like that.
A few months ago I bought an inexpensive 2-bulb T8 (34 watt bulbs) fixture to replace an old 2-bulb T12 (40 watt bulbs) fixture. I similarly put the Kill-A-Watt meter on these fixtures. The new T8 had a pf of 0.49 and the pf of the old T12 was considerably higher (don't remember what it was). I thought I was buying a high efficiency fixture, and I'm not sure that the goal was accomplished. I don't know the lumen output of each fixture, so an exact efficiency determination cannot be made.
Lesson learned. In the future when I buy CFL's, I will compare brands of the same watt rating based on the milliamp rating, and buy CFL's with the lowest milliamp rating for the wattage I want.
House volts = 122
New CFL: 12 watts, 23 va, 0.19 amps, pf = .53
Old CFL: 16 watts, 18 va, 0.15 amps, pf = .89
The new CFL appears to be much less efficient than the old CFL. Also, the new CFL is using 23 watts/equivalent of power if compared to an incandescent bulb. CFL's are rated at 44-80 lumens/watt, and incandescent are rated at 7-24 lumens/watt. While it appears that the new CFL is producing more lumens/watt than an incandescent bulb, it is not nearly as efficient as I would have assumed, and particularly as compared to the old CFL.
While the lack of efficiency does not translate to watts used, and therefore does not directly impact my electric bill, it seems to me that there should be an understandable standard manufacturers of CFL's, perhaps all lighting bulbs, should be required to label so that a retail customer can easily know the efficiency of various CFL's. Perhaps lumens/va rather than lumens/watt. Although most retail customers probably don't really know what a watt is, they certainly don't know what volt-amps are. So maybe an energy standard of lumens/power unit, or something like that.
A few months ago I bought an inexpensive 2-bulb T8 (34 watt bulbs) fixture to replace an old 2-bulb T12 (40 watt bulbs) fixture. I similarly put the Kill-A-Watt meter on these fixtures. The new T8 had a pf of 0.49 and the pf of the old T12 was considerably higher (don't remember what it was). I thought I was buying a high efficiency fixture, and I'm not sure that the goal was accomplished. I don't know the lumen output of each fixture, so an exact efficiency determination cannot be made.
Lesson learned. In the future when I buy CFL's, I will compare brands of the same watt rating based on the milliamp rating, and buy CFL's with the lowest milliamp rating for the wattage I want.