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The True Cost of Standby Power
Luther19 writes, "How much do all of our computers and electronic devices sitting in standby mode cost us? The author of the article concludes that he could save $24.44 per year by switching out wasteful power supplies. The article also touches on a global initiative to cut down on standby power, called '1-Watt': 'The idea has been promoted by the IEA, which first developed an international 1-Watt plan back in 1999. Countries like Australia and Korea have signed on officially, while countries like the US require 1-Watt in government procurement, which will have ripple effects throughout the economy. The goal of the program is to have standby power usage fall below 1W in all products by 2010.'" It's estimated that in industrialized countries, devices on standby consume on average 4% of the power used.
Mind you: it's not always a device with an explicit stand-by mode. I once used such a wattmeter on all devices and learned that my 40W lamp with a seemingly #$%#$% cheap transformer was using 25W while "off"!
:S
Factoid: if all American households would not use the stand-by mode of their TV, an entire _nuclear_ power plant can be saved on a national level.
I just finished a comprehensive audit of all the electricity drawing devices in my house:
o ld_energ.html
:-)
http://digitalcrusader.ca/archives/2006/10/househ
I learned that my Stereo system consumes 22W when on "standby" and only about 35W when in use - what a total waste! So I put it on a power bar. My older TV is 0W standby, and all the newer Wall Warts that I have seem to be OK as well - 4 of them together only rate 1W. Your milege may vary
augment your senses: http://sensebridge.net/
I can tell your from experience (this is one of the more popular demonstrations in the power engineering lab) that cheap watt-meters can be terribly wrong with loads that are not simple resistors.
A transformer with no load (probably in your case - most lamps with halogen lamps have the switch on the secondary side) is almost a perfect inductive load. Current and voltage are not in sync and the (real) power is very close to zero.
Not all instruments can show this correctly. Especially not if they measure voltage and current separately without taking the phase shift in account (as is often the case with cheap stuff). Switching power supplies (almost everything electronic uses one of those today) are also hard to measure. You need a high sampling frequency if you want to accurately measure the power they draw from the mains. Again, consumer instruments don't have this because fast AD converters are expensive.
Just about the _only_ instrument I would trust outside the lab is the watt-meter the power distribution company installed in your house. These things have to go through very thorough testing before they are approved.