They suck electricity even when you're not using them. By Jeff Bertolucci, Contributing Writer May 5, 2011 They are the night stalkers: vampire appliances (TVs, computers, DVD players and cell phone chargers) that siphon energy around the clock, even when idle. The average U.S. home has 40 such devices that draw power continuously and account for nearly 10% of home energy use, according to the Lawrence Berkeley National Laboratory. The good news is that with the proper equipment you can drive a stake through the heart of these energy wasters. A good first step is the Belkin Conserve Smart AV, a $30 surge protector/power strip designed for home-entertainment systems. It automatically shuts off components, such as a gaming console, receiver and speakers, when you turn off your TV. Plug your television into Conserve Smart AV's green master outlet, and when the set is turned off, the device cuts power to peripheral devices connected to five of its seven outlets. The two outlets that remain are for gadgets, such as cable set-top boxes and DVRs, that need 24/7 connectivity to download program guides and record shows. Belkin estimates that Conserve Smart AV can save up to $76 per year in energy costs, assuming your home-entertainment system includes a DVD player, VCR, game console, subwoofer and amplifier that are left on (but not active) 19 hours a day. Power down. You don't have to spend money to slay a vampire. A simple step, such as unplugging cell phones and MP3 players once they're charged, is a helpful cost-cutting suggestion from the Environmental Protection Agency. If you use a desktop computer with a separate monitor, configure its energy settings so that it powers down when not in use; that alone could save you up to $85 per year, the EPA says. (Laptops power down automatically, but desktops -- particularly older ones -- may not.) Look for home appliances, such as microwaves and cordless phones, with low standby-power ratings. The Web site for the Federal Emergency Management Agency's Standby Power Data Center can tell you how much energy a device uses when it's idle. Just enter a product type, model number, or company or brand name, and the FEMA Center database will reveal which of the products meet the agency's standby-power requirements. Advertisement Other options. Standard wall chargers for cell phones and MP3 players act like Dracula, too, by continuing to feed power to a device after it's fully charged and also by drawing small amounts of energy even when no device is attached. Unfortunately, spending money on a gadget that's supposed to fix the problem may not pay off. The Ventev EcoCharge ($30 to $35) senses when a device is charged, then sends power only when the device's software requests it. The iPhone/iPod model is $35; two versions with either a mini- or micro-USB connector (for other phones and also for portable media players) cost $30 each. Your energy savings may total only a few dollars per year, however, depending on the efficiency of the wall charger you're switching from, so simply unplugging your devices may be the better option. If you're truly on a crusade to hunt down energy wasters, you'll need a measuring tool. Consider an inexpensive energy monitor such as P3 International's Kill A Watt EZ. Priced at about $35, this handy device plugs into a wall outlet. Connect an appliance to the Kill A Watt, and it will measure how many kilowatt-hours of energy are being used and estimate how much the appliance costs to operate. The next move is up to you, Van Helsing. Follow Kiplinger on Twitter.