Is a zero-draw phone charger worth it?

AT&T says its upcoming Zero Charger doesn't use electricity while your smartphone is unplugged. But is it really worth it?

AT&T says its upcoming Zero Charger is a vampire-killer -- that is, it doesn't sip precious electricity while your smartphone is unplugged.

But is it really worth it?

Joseph Kaminski at SmartPlanet sister site CNET put three popular phone chargers to the test to see if mobile phone manufacturers are offering you real savings -- or just trying to slip you another pricey accessory.

The suspects: Chargers for the Apple iPhone, Motorola Droid and Palm Pre.

The test: Each charger was tested over 16 hours in CNET labs.

The verdict: Modern cell phone chargers draw minute amounts of power when plugged in.

Kaminski reports:

They all drew an extremely low amount of power and cost the user very little per year, ranging from 6 to 22 cents based on our calculations. If we assume $29 (the cost of your average charger, assuming AT&T's would cost the same) and divide it by 12 cents (the average of all four chargers' annual costs), it would take 241 years for it to pay for itself.

In other words: if you're interested in saving significant amounts of money on your electrical bill, you're better off shutting off a light when you leave the room than buying a new "zero draw" charger.

In the meantime, here's hoping that zero-draw chargers become the global standard. After all, even little amounts of power can add up worldwide.

This post was originally published on Smartplanet.com