Slaying the Power Vampires

Electronic News, August 16, 1999 by Charles Small

When you turn a piece of electrical equipment off, it's off, right?

Wrong!

Like the legendary vampire, certain home appliances and electronics, live on in the world of the undead, drawing power even when they are ostensibly turned off. These products include televisions, VCRs, telephone answering machines, cordless phones, portable power tools and office equipment.

This phenomenon is known as leaking electricity. The EPA estimates that leaking electricity consumes 45 billion kilowatt-hours of electricity each year -- nearly 5 percent of total residential electricity use -- and costs U.S. consumers more than $3.5 billion annually.

Cordless and portable products with internal rechargeable batteries, as well as standalone battery chargers and recharging stations for cellular phones, are responsible for leaking electricity. This is particularly true of lower end devices with less sophisticated circuitry. In these products, the battery charger continues to draw power even after the battery has been fully charged.

You can easily verify this by touching any wallpack power supply. It will be warm even when it is not powering anything. Such wallpacks are called "power vampires."

Power-vampire wallpacks are shipped with consumer goods simply because they are the least expensive supplies available. More efficient wallpacks could be made using better transformers and switching regulators -- but at higher cost. Governments around the world are very aware of the leaking-electricity phenomenon and know that manufacturers will not switch to greener wallpacks out of the goodness of their hearts. Therefore, stricter government regulation for wallpacks -- especially in Europe -- is expected soon.