Electricity basics
How Much Does Standby Electricity Cost?
Calculate the cost of measured standby watts. Check which devices can be switched off safely and avoid assuming every plugged-in appliance wastes power.
A continuous standby load costs watts ÷ 1,000 × hours × your rate. Measure the device's actual standby mode. Keep required safety and network functions powered.
On this page
A device can look switched off while still using electricity. A display, remote receiver, clock, or network connection may remain active.
The DOE standby guidance describes power use in low-power modes. The useful question is how much your specific device uses, for how long, and whether its standby function is needed.
Identify the actual low-power mode
“Off,” “sleep,” and “network standby” can mean different things. A television with quick-start enabled may not behave like one with that feature disabled. A computer may be asleep rather than fully shut down.
Check the manual before changing a setting. Some devices carry out updates, keep records, or maintain connections while idle. Do not assume every function is unnecessary.
Calculate a steady standby load
For a continuous 365-day year, there are 8,760 hours. A hypothetical steady 3 W load uses 3 ÷ 1,000 × 8,760 = 26.28 kWh.
At an example $0.20/kWh, the annual cost is about $5.26. A hypothetical 20 W continuous load would use 175.2 kWh and cost $35.04 at the same rate.
Apply the same arithmetic to the standby power you measure. Record each mode separately when a device changes its power use during the day.
If a device is actively used for part of the year, subtract those active hours from the standby period. Do not count the same hours in both modes.
Measure rather than guess
A compatible plug-in monitor can help, but check its resolution and accuracy at low power. A very small difference may be below what the meter reliably measures.
The P3 manual distinguishes real watts from other electrical readings. Use watts or accumulated kWh, not volt-amps, in a running-cost calculation.
- Put the device into the mode you want to assess.
- Allow its normal transition or update process to finish.
- Observe whether the power remains steady or varies.
- Record energy over enough time for a useful reading.
- Note which features were enabled during the check.
These readings show the device's use during your measurement period. To calculate a home's idle load, include the other devices and their standby hours.
Switch off selectively
Natural Resources Canada discusses standby functions and suitable power-control options. The choice depends on the equipment and the services you need.
A switchable outlet or suitable power bar can simplify control of compatible low-load accessories. Follow every device's instructions and the power-control device's ratings. Do not apply this idea to portable heaters.
Keep alarms, required refrigeration, medical equipment, and essential network devices powered as their instructions require. Also consider whether a shared switch would interrupt recording, updates, or another user's work.
Prioritize the useful saving
Compare the measured annual cost with the effort or equipment cost of eliminating it. A new smart plug can consume energy itself. Include that consumption in the total energy comparison.
Use the electricity calculator with the hours the device actually spends in standby. Add the measured loads and their standby hours to calculate the total cost of the devices you can safely switch off.