Berkeley Lab

Frequently Asked Questions (FAQs)

What exactly is standby power and why is it necessary?

Most experts agree that standby power is electricity used by appliances and equipment while they are switched off or not performing their primary function. That power is consumed by power supplies (the black cubes—sometimes called “vampires”—converting AC into DC), the circuits and sensors needed to receive a remote signal, soft keypads and displays including miscellaneous LED status lights. Standby power use is also caused by circuits that continue to be energized even when the device is “off”.

That definition is attractive to a lay person but inadequate for technical purposes. An international technical standards committee is developing a definition and test procedure.

How can I identify products that draw standby power?

Almost any product with an external power supply, remote control, continuous display (including an LED), or charges batteries will draw power continuously. Sometimes there is no obvious sign of continuous power consumption and you need a meter to be certain.

How much standby does my TV, microwave, etc. use?

We measured standby power in hundreds of products. See here for a ranges of Standby Power in chart format and a ranges of Standby Power in a table. Other excellent sources exist, notably an Australian measurement campaign, ENERGY STAR, and the Federal Energy Management Program.

What are Watts?

Watts is a measure of power (technically, Joules/second) analogous to speed (miles/hour). So you need to convert the power into energy (like speed into distance). Here’s an easy conversion factor: if a device draws 1 watt constantly for a year, then its energy consumption was 9 kWh. That corresponds to about $1.00.

So, when the chart says 5 watts, that’s 5 x 9 = 45 kWh/year = $5/year. You’ll quickly see that almost any single device consumes very little in annual electricity use but, when multiplied by 40+ products, the sum is significant.

How can I reduce standby power use in my home?

It’s not easy, but here are some suggestions:

  • If you aren’t frequently using a device, unplug it. (This works fine for the 6th TV in the guest bedroom or the VCR.) Warning, 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.
  • When shopping, search for low standby products. (Asking a salesperson will probably be a waste of time.) ENERGY STAR products have lower standby.
  • Buy a low-cost watt-meter, measure the devices in your home and take targeted action. You will certainly be surprised at what you discover and this exercise might even pay back the cost of the meter in savings. A list of watt-meters is here.

Limited research suggests that an informed and aggressive approach can reduce standby use by about 30%. Frankly, there are more productive ways to save energy with an investment of an hour but if high standby energy use stands between you and the goal of a zero energy home, then it’s an hour well spent.

Is standby power use necessary?

Sometimes. Certain appliance functions do require small amounts of electricity include:

  • Maintaining signal reception capability (for remote control, telephone or network signal)
  • Monitoring temperature or other conditions (such as in a refrigerator)
  • Powering an internal clock
  • Battery charging
  • Continuous display

Good design can make the power requirements for these functions very low (but not yet zero).

How much power is used for standby in the US?…Worldwide?

Nobody knows for sure, but it’s typically 5-10% of residential electricity use in most developed countries and a rising fraction in the developing countries (especially in the cities). Standby power in commercial buildings is smaller but still significant. Altogether, standby power use is roughly responsible for 1% of global CO2 emissions.

Is standby growing or shrinking?

It’s probably growing. Programs directed at consumer electronics have stimulated manufacturers to cut standby power use in many products. At the same time, the number of new appliances that continuously draw power is increasing rapidly, especially in the developing countries. We suspect that standby continues to increase. Recent Japanese policies to reduce standby appear to be effective since the latest studies (2008) suggest that standby power is decreasing. The reduction is a result of both improved technologies and heightened consumer awareness.

Can standby power consumption be reduced?

Yes. Many new technologies can improve the efficiency of power supplies, manage power use more carefully, and limit power use of displays. We believe that it is technically feasible to reduce standby power by 75% overall. Most savings will be less than a watt, but other cases will be as large as 10 watts.

Who coined the term “energy vampire”?

We don’t know. However, the term has been around since before 2001. The vampire refers to the external power supply—the little black cubes—which have two teeth (the plugs) and “suck” electricity all night. The term “leaking electricity” was coined by a Swedish engineer, Eje Sandberg, in 1993.