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A dead-easy way to kill vampire power

Belkin's Conserve Power Switch is a simple off switch that fits over an electrical outlet to cut standby power, the energy that's wasted when gadgets and appliances are plugged in but not running.

Martin LaMonica/CNET

As much as 10 percent of your electricity bill is simply being sucked away for no useful purpose. Blame standby, or vampire, power.

Belkin this month released perhaps the simplest way to cut that standby power with its Conserve Power Switch. The small gadget is just a switch in a handy format that cuts the flow of power to anything that plugs into it.

There's not much to this device, but that's its appeal. The Power Switch, which costs $6.99, plugs into a regular outlet and you plug a device into that. When you want to use your coffee machine, flick it on and a small green light turns on to indicate the plug is live.

Could this simple act actually be worth it? Depending on what power source you intend to cut off, this little gadget or one like it can pay for itself in a few years.

Lawrence Berkeley National Laboratory calculates that the average microwave uses 3 watts when it's off. That means if you only turn it on occasionally, you could save about $3 a year based on the national average electricity price by cutting the standby power.

By contrast, the standby power on the average coffee maker is only 1 watt, so it would take years to recoup the purchase price. That said, it's not exactly difficult to switch on an outlet before charging your phone or other electronic gadget. (For comparison, a PC in my office consumed 2 watts when off, a monitor 1 watt, and an IP phone 4 watts. See a full chart here.)

For multiple gadgets, such as a home computing setup or entertainment center, the better way to go is a power strip, or surge protector. You can manually cut the power to everything on a strip or buy a smart strip that cuts power to peripherals when a PC or TV is off. DVRs and set-top boxes are heavy users of stand-by power, estimated to be about 21 watts and, because they're on all the time, cost in the neighborhood of $2 billion a year in wasted energy.

Since the Conserve Power Switch is smaller than the palm of your hand, it's well-suited for outlets that you have easy access to, such as counters.

If you're curious, handheld power meters, such as the Kill A Watt, will tell you what different devices consume. Belkin's Insight power meter displays the standby or run-time power along with projected annual cost and carbon emissions. It also sells a simple timer.

Belkin last year purchased Zensi, a startup that's developed a highly sophisticated way to recognize the voltage signature of different devices from a single outlet, but it has yet to commercialize that technology. It seems that when it comes to slaying vampires, perhaps the best weapon is simplicity.

This article was corrected at 9:55 a.m. PT with corrections to the stand-by power averages from Lawrence Berkeley National Laboratory.