Winter has been relatively mild and virtually snow-free so far in many regions. That’s helped take the chill off utility costs. In fact, the people who monitor such things say electric bills are down, especially in areas like the mid-Atlantic.

But there’s a way to cut costs even more, though it may not be immediately obvious:

Slay the vampires.

“Vampire power,” also known as “standby power,” is electricity consumed by electronic devices and appliances even when they are switched off or in standby mode. Their external power supplies — typically, little black cubes with two teeth (the plugs) — “suck” electricity, according to the Lawrence Berkeley National Laboratory, which has measured standby power in hundreds of devices.

“Americans have an increasing number of devices that get plugged in and charged up,” said Ronnie Kweller, spokeswoman for the Alliance to Save Energy in Washington, D.C.

Consider that a single house, according to some estimates, may have as many as four or five dozen of these devices contributing greatly to a monthly electric bill.

How much? The folks at Lawrence Berkeley offer a conversion factor:

If a device draws one watt constantly for a year, then its energy consumption is 9 kWh. That corresponds to about $1. So when the chart on the lab’s website lists 5 watts for a device, that means five times nine, which equals 45 kWh a year, which equals $5 a year.

Multiply that by four or five dozen and, voila, a not-insignificant expense.

Kweller’s personal example: “When the switch to digital television happened, we got a box from the cable company that had to be plugged into our TV. It has a light that is on all the time, so I assume it’s drawing power 24/7.”

Most houses have more than one cable box, so those eternal lights multiply.

Her television draws power, too, Kweller said, “though, as an Energy Star model, at least the standby power it is using is less than a model that isn’t Energy Star-qualified.”

Some devices are definitely energy hogs. Individually, they may not consume all that much electricity. Together, they add up to a hefty, though hard to isolate, part of your monthly bill.

Let’s start with your computer — the Department of Energy offers some guidelines to help you decide whether to turn it off.

Though there is a small surge in energy use when a computer starts up, that is still less than the energy used when the computer is running for long periods of time.

For energy savings and convenience, consider turning off the monitor if you aren’t going to use your PC for more than 20 minutes. Turn off both the CPU and the monitor if you’re not going to use it for more than two hours.

Make sure monitors, printers and other accessories are on a power strip/surge protector. When the equipment is not in use for extended periods, turn off the switch on the power strip to prevent the devices from drawing power even when they are shut off.

If you don’t use a power strip, unplug extra equipment when it’s not in use.

Most personal computers will reach the end of their usefulness because of advances in technology long before the effects of being switched on and off multiple times has a negative effect on their service lives. The less time a personal computer is on, however, the longer it will last.

A computer also produces heat, so turning it off also will reduce your home’s cooling load in warmer weather.

Do you have an iPhone, an iPad, an iPod, an Amazon Kindle, or similar devices made by other manufacturers?

Each comes with a charger, doesn’t it? The iPhone and iPod use the same ones, but the iPad and the Kindle have their own.

If your mobile device is not being charged, be sure to unplug the charger, too, or it will continue to draw power as well and run up your bill, Kweller said.

If you attached all your mobile stuff to a power strip or a similar device designed for use with chargers, reupped their power all at once, then shut off the switch to the strip, it might cut your power costs.

The list of devices drawing down standby power is endless: DVD and CD players, Wii game consoles, digital clocks, DVR boxes, WiFi routers and cable modems, fax machines (yes, some people still have to send forms), burglar alarms, stoves and microwaves.

Standby power consumes 5 to 10 percent of all electricity in developed countries, but there is some debate whether consumption is growing, the folks at Lawrence Berkeley say.

An informed and aggressive approach can cut standby use by about 30 percent.

Figuring out how to do that may take some time. But it might help reduce your monthly contribution to the well-being of the local utility company’s stockholders.

Is standby power really necessary?

Sometimes, it is, the Lawrence Berkeley National Laboratory says. Certain appliance functions that require small amounts of electricity include:

• Maintaining signal-reception capability (for remote control, telephone or network signals)

• Monitoring temperature or other conditions (such as in refrigerators)

• Powering an internal clock

• Battery-charging

• Continuous display (such as when a microwave clock stays on when the oven itself is off)

— Lawrence Berkeley National Laboratory

How to power down

• Unplug a device if you aren’t frequently using it. Don’t frequently unplug and plug in appliances because you could get electrocuted from frayed wires and plugs.

• Use a switchable power strip for clusters of computer or video products. That way, you can switch everything to zero with one action.

• Search for low standby-power products when shopping. (Energy Star-qualified products have lower standby power).

• Buy a low-cost watt meter, measure the devices in your home, and take targeted action. The exercise might even recoup the cost of the meter in savings.

— Lawrence Berkeley National Laboratory