24×7 Hidden Waste of Power
zondag, november 4th, 2007In an old box I found a power meter: a small device to measure power usage for electric equipment. Currently: 158 W for a pc, a monitor and a audio set. Okay. Could be better maybe, nevertheless. Once I switched everything off, 52W was still in use. Huh? All devices off and still eating power at 1/3 of the in-use rate? What’s this.
A little more research showed that the home equipment has a pretty large ‘24×7 power usage’ . As long as the power cord is plugged in, the devices are still in use. Okay, some devices don’t even have an ‘off’ switch, such as a network switch (strange word joke, a switch without a power switch!). But the other systems are totally off usage and still burn. What did I find out?
| Device | Usage | Power Off Usage | Model |
| Personal Computer | 90-120W | 7W | clone, AMD Athlon 3000+, 370W power supply |
| Printer | 16W | 16W | HP Business Inkjet 2300Duplex & Network |
| Network Switch | 10W | 10W | D-Link Gigabyte |
| Monitor | 30W | 7W | Philips 170P |
| Audio Set | 7W | 7W | Sansui ‘1985′ |
Personal Computer
Even when switched off, the computer eats 12W. The lights inside, on the motherboard, are lit. The machine has built-in functions such as wake-on-lan, which can turn the machine on with a special sign on the network. So, the device is listening on the network waiting for a command to re-awake. The 90-120W’in-use’ power is depends on the work it has to do: reloading a web page will increase the usage with 10W.
Monitor
Don’t know why, but the monitor still eats 7W for doing nothing. Okay, there is a USB connector inside. Is that the real cause? Can’t sure.
Switch
The network switch can’t be switched off, but is of no use when all devices are down. It uses 10W, under any usage.
 Printer
The above are things I was more or less (pc) aware of. But this printer is the absolute top: it uses the same 16W, when it’s on or off. Only during printing the usage increases, but I just haven’t measured that. It’s hardly relevant, probably. The damn is in the 16 W 14×7 usage.
Solution
The only way to ged rid of this is a big power switch on the power distributors. And put it off every night!

