Home Energy · Audit
Standby Power Audit
Add up the power your devices draw while switched off or idle, and see what it costs per year at your tariff.
Standby load
0 W
Annual energy
0 kWh
Annual cost
Enter your tariff.
Annual CO₂e
Optional — choose a factor.
Standby devices
Add each device and the standby watts you measured with a plug-in energy meter or found on its data sheet.
No devices yet. Use Add to enter your own, or Load example to see how it works.
| Device | Watts | Count | kWh/yr | Cost |
|---|
Smart-plug payback check
Enter your own figures. Nothing here is assumed.
From the plug's data sheet or a meter. Counted 24 h/day.
Enter your tariff and all three values to see the saving and payback.
Active, standby and off
- Active — the device is doing its main job (playing, heating, charging).
- Standby — it is waiting or ready (for a remote, a network signal, a timer) and still drawing power.
- Off — depending on the product, it may draw nothing or a small amount; "off" does not always mean zero. A plug-in energy meter shows which.
Small loads add up because they run for many hours: energy in kWh = watts × hours ÷ 1000, so a load left on all year uses watts × 24 × 365 ÷ 1000 kWh.
Formula
Annual kWh = watts × count × hours/day × days/year ÷ 1000
Annual cost = kWh × tariff
Annual CO₂e = kWh × chosen electricity factor (optional)
Smart-plug net kWh = (watts switched off × hours off − plug watts × 24) × days ÷ 1000
Example: 10 W drawn continuously is 10 × 24 × 365 ÷ 1000 = 87.6 kWh a year; multiply by your tariff for the cost. 15 W for 24 h a day all year is 15 × 24 × 365 ÷ 1000 = 131.4 kWh. See calculation methodology. To find your always-on load from the meter first, follow the DIY home energy audit guide.