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 If you are like most people, you probably have many electronic devices in your home using AC/DC power adapters. Older power adapters are not very efficient, anywhere between 20% - 60%. Newer power adapters that meet the voluntary Energy Star standards have power efficiency as high as 85% minimum.
 Energy Star [1] mandates the International Efficiency Marking Protocol [2]. If a power adapter meets the protocol then it will have a Roman numeral with a circle around as per the figure in the international protocol [2].
If the Roman numeral is III or higher the power supply will have at least 84% efficiency (>50W load) and consume less than 0.5W - 0.75W (no load).
Consult the International Efficiency Marking Protocol documentation for an exact summary for each Roman numeral.
[1] Energy Star - External Power Supplies
[2] International Efficiency Marking Protocol
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Friday, October 9, 2009 at 12:01AM |
Reader Comments (1)
I was just thinking about this the other day as I went around my house documenting how many kilowatts I was using daily. Just couldn't figure out those AC/DC adapters, especially if only amps and volts are written on them. How is one to extrapolate watts from them? Thank you for providing this wonderful blog!