Wallwarts

No, not unless you keep hitting it with the hoover...

Wall Warts are built for continuous duty. Like any electronic equipment though, if they run hot (due to being overloaded, or whatever), the life will be shortened. Also, if you have a lot of lightning surges without any protection, you might lose one occasionally.

Beachcomber

No, but keep in mind that the do consume energy while plugged in, even if they are not powering the associated equipment.

Charles Perry P.E.

Thanks to all you good-humored and knowledgeable correspondents I won't have to lose any more sleep over those little monsters.

Have you heard anything more about the estimate of the amount of energy wasted annually from wall warts? I know it was a big buzz a few years ago.

Here is a figure from one source:

Researchers at Lawrence Berkeley National Labs estimate that US households waste about $3.5 billion in electricity a year on power supply standby losses alone.

Currently, the push by the EPA and CEC (California Energy Commission) is to improve the efficiency of power supplies in computers and other electronic devices (TVs, etc). They are horribly inefficient, particularly when lightly loaded (as they almost always are).

Charles Perry P.E.

Thanks, I thought you would know. I am thinking the time may have come for a parallel low voltage system ion houses with some standardization in low voltage appliances so we only have a single, high efficiency supply, perhaps battery backed up. I know there are dozens of wall warts around my house for all the various things. I try to keep them unplugged or switched off when not in use but it doesn't always happen. There are 5 on this PC alone.

Depends on the unit, but one with 9v DC 300ma output unloaded I tested uses

1 volt-amp. Another one used for recharging a hand vac doesn't even get the slightest bit warm unloaded. Probably less than a watt used when unloaded. Seems like a waste of time to even be concerned about the power drawn when not in use.

-S

Indeed! Learning to turn off lights, or removing a 40 W often-used bulb from somewhere would be MUCH more significant. Sure, the total energy used across the nation might not be small, but the total wasted energy is probably enormous compared with this!! --Phil

For PC-related things, I often grab the power for ancilliary devices from the PC's power supply. That works fine for some external disks, scanners, and ethernet hubs I've used, and it also means they go off when you switch the PC off. It's a non-starter for some external modems and printers though, as neither external power supply terminal is anywhere near 0V relative to the connection to the PC, so they have to have isolated power supplies.