'Phantom load' lurks in homes

The Republican Newsroom By The Republican Newsroom The Republican
on September 08, 2008 at 7:34 AM, updated September 08, 2008 at 1:02 PM


"Turn off that TV! You're running up the electric bill!"

That frustrated plea from parents is not entirely correct. You are probably running up the electric bill even when the television set is switched off.

A host of appliances and electric devices throughout the home draw what is called a "phantom load," an amount of electricity that keeps them primed for use or their displays lit up. (A quick test: how many digital clock displays can you find on devices in your home?).

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Indeed, as much as 5 to 10 percent of an annual household electric bill is wasted through phantom loads, studies have found.

"It's the load you don't know you're using. It happens because many of these are 'instant on' devices. A TV is always drawing electricity because it is sitting and waiting for the remote control to signal it on," said Lacey P. Girard of Western Massachusetts Electric Co. last week. "They're not drawing as much power as when they are turned on, but collectively, their use does add up."

For example, when your PC is fired up, the computer and monitor might be drawing 250 watts of power. But you might be using the system only two hours a day, for a total of 15 kilowatt-hours of electricity a month (the standard unit to measure electricity use.) At current rates, that will add about $2.78 to your monthly bill.

When that computer system is off but plugged in, the system may still be drawing 5 watts. But it is doing that for 22 hours a day, for a total of 3.3 kilowatt-hours a month, not an insignificant amount of power.

If the system is in a sleep mode when not in use, though, the monthly power use climbs to 12.5 kilowatt-hours, or about $2.31 a month in power costs.

Most people have 20 or more devices in their home drawing phantom loads, from cell phone chargers (1 or 2 watts even when nothing is charging) to garage door openers (perhaps 12 watts) to digital cable boxes (about 35 watts when on and just as many watts when off).

A household with the typical assortment of electronics may be drawing 80 watts of electricity even in the dead of night, when nothing is being used. With electricity costing about 17 to 19 cents a kilowatt-hour in most of the Pioneer Valley, that means $9 or $10 a month of phantom load costs.

Can one eliminate this waste of electricity entirely?

Not without sacrifice.

Digital cable boxes and digital video recorders, such as TiVo units, are two of the larger power gluttons in the home, drawing about 35 watts each of phantom load. However, if you unplug the cable box, you lose all the interactive information on it, such as the program guide.

And it may take anywhere from 10 minutes to 24 hours for the cable company's server to completely restore all of that information. And, with a digital recorder, such as TiVo, unplugging the unit would mean that you cannot record anything.

However, for the computer room and for entertainment center equipment that does not need to stay on 24/7, there is a solution, said Tilman Wolf, an associate professor of electrical and computer engineering at the University of Massachusetts-Amherst.

"The best thing to do is to buy a power strip that has an on-off switch on it," he said. "Turn it off when the equipment isn't in use. When it's off, nothing connected to it draws power."

For computer systems, including peripheral equipment such as routers and printers, that solution makes a lot of sense. At night or during vacations, a lot of electricity can be saved by turning off the power strip.

However, the big power sinkholes in a home are the motorized devices, such as refrigerators, basement dehumidifiers, and attic fans that operate around the clock, said Wolf.

Both attic fans and dehumidifiers can draw 400 watts when operating, and a 25-cubic-foot, side-by-side refrigerator can draw twice that amount (although it shuts down intermittently through the day).

The fan, if used just 12 hours a day, might cost almost $25 a month to operate. The dehumidifier, if run all day, might cost almost $50 a month. And the refrigerator might add $34 a month to the electric bill.

Wolf said that replacing these devices with the most energy-efficient models possible might be the best solution.

"With appliances, it's a tough decision," he said. "You can spend $1,000 for a new refrigerator. But spending the extra dollars to get an efficient appliance might mean savings each month that can really add up."

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