1
\$\begingroup\$

Suppose I have a TV plugged in and it is connected to a power outlet which is also turned on. This appliance is "turned on" and on "stand by mode". It consumes energy I think just to light up that little red LED to tell you it's switched on (does it use electricity for anything else?)

Now suppose I have a laptop or mobile charger that is plugged into a power outlet that is permanently turned on. If this charger is just sitting there without being plugged into anything .... is it consuming energy? Is this considered to be another "stand by device" which consumes energy for me? Will this impact my power bills?

In the extreme case: if a power outlet is turned on, is this consuming any energy?

\$\endgroup\$
  • \$\begingroup\$ Welcome to EE.SE. I have given this much thought myself. But if low-power or sleep-mode reduces power consumption by 99%, then it is doing some good. That 1% is being used to detect if you use the remote to turn ON the TV. \$\endgroup\$ – Sparky256 Nov 6 '18 at 1:07
  • \$\begingroup\$ Yes, a tiny amount of energy is consumed by these devices. Old ones can be very bad about it, but newer ones are usually designed with this in mind. In the power outlet case: No, not unless it's got some little light or something on it. I mean, I guess you could count the minuscule leakage current through the air between the live and neutral wires, and the slightly larger but still tiny parasitic capacitances... But that would be extremely pedantic. Your power meter probably can't even measure that. \$\endgroup\$ – Hearth Nov 6 '18 at 1:20
1
\$\begingroup\$

Yes. Vampiric power drain can happen even in a switching power supply that has no output load. It may be small, but it is non-zero. The internal ICs and passive components will still consume some power.

\$\endgroup\$
1
\$\begingroup\$

Also worth noting is that EU has regulations on how much power they can draw in standby mode. For devices not connected to the network it's 0.5W, for network connected devices it's 8 or 12 watts.

Let's take a compliant, not networked device: 0.5W * 24h * 365 = 4.38 kWh - where I live this would cost me around half a euro. Yearly, per device.

Source: https://ec.europa.eu/energy/en/topics/energy-efficiency/energy-efficient-products/standby

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.