Q. Many devices that are “always on” while seemingly “off” draw power so that they can spring into action on demand. How much electricity does a television, for example, use when plugged in but not turned on?
A. Lawrence Berkeley National Laboratory has done extensive studies of standby power since 1996 for the Department of Energy. In particularly inefficient appliances, standby power use can be as high as 20 watts.
“For a single appliance, this may not seem like much,” the laboratory’s Web site says, “but when we add up the power use of the billions of appliances in the U.S., the power consumption of appliances that are not being used is substantial.”
An exact reading of the standby power drawn by an individual appliance can be obtained only by using a fairly expensive energy meter or by turning off all the rest of a home’s appliances and checking the utility meter.
For making an estimate, a laboratory Web site — standby.lbl.gov/data.html — provides tables of the minimum, average and maximum power used by appliances that cannot be switched off completely without being unplugged. For television sets, the laboratory estimates a minimum power use of zero watts, an average of 5 watts and a maximum of 21.6 watts.
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This question and answer piece was in the New York Times this morning. My husband and I have replaced the light bulbs that we use to most or are left on the longest (i.e. porch lights at night) with energy efficient bulbs. We've plugged all our "always on" things into power strips we can turn off at night or when we are gone during the day (cell phone chargers, tv, dvd player, laptops etc.) We'll replace other lightbulbs as they go out. Just this small thing has brought our electric bill down consistently to below 2001 levels...in cost alone. Its easy to brush aside small things as too insignificant to bother with. But these are all soooo easy to do and the cumulative effect can be very significant.

Harmony House