Smart Plug Savings Calculator
Find out how much standby power is costing you — and whether smart plugs will pay for themselves.
Quick Start
Tip: You can measure actual standby wattage with a plug-in energy monitor (available for €10–15). Measured values are more accurate than label estimates.
Devices on Standby
Add devices that stay plugged in when not in use. The idle hours column is how long each device sits in standby per day.
Results
Add devices and click Calculate to see your standby costs.
Based on rated standby wattage. Actual draw varies by device and firmware. Measure with a plug-in energy monitor for precise figures.
Typical standby wattage reference
Note: routers, smart home hubs and security cameras need to stay on — do not connect these to smart plugs.
Smart plugs and standby power explained
Do smart plugs actually save money? +
For devices that draw meaningful standby power for many hours a day, yes. A games console drawing 8 W for 14 idle hours a day costs around €26/year in standby alone. A smart plug set to cut power overnight pays for itself in under a year. For devices drawing less than 1 W, the savings are minimal and the payback takes many years.
Which devices are worth putting on a smart plug? +
Good candidates: TV entertainment setups (TV + console + receiver), desktop PCs left idle overnight, printers, AV equipment, and microwave ovens. Poor candidates: routers, smart home hubs, security cameras, refrigerators, and anything that needs to be reachable 24/7. If cutting power would cause data loss or require a lengthy restart, skip it.
How do I find the standby wattage of my devices? +
Three ways: (1) Check the product manual or manufacturer's website — standby power is often listed in the spec sheet. (2) Use a plug-in energy monitor (€10–15 online), which shows real-time wattage. (3) Use the reference values in the table above as a starting point. Measured values are always more accurate than label estimates.
Does a smart plug itself use electricity? +
Yes — a Wi-Fi smart plug typically draws 0.5–2 W continuously to maintain its network connection. This is factored into the 90% efficiency default in this calculator. If your standby device draws less than 2–3 W, the smart plug's own consumption may partially offset the saving.
How standby power and smart plug savings work
What is standby power?
Standby power (also called phantom load or vampire power) is the electricity consumed by a device when it is plugged in but not actively in use. This includes devices in sleep mode, waiting for a remote signal, or keeping an internal clock running. Most modern devices draw 0.5–5 W on standby, but older AV equipment and games consoles can draw 10–20 W.
The formula
Annual standby cost = (standby watts ÷ 1000) × idle hours per day × 365 × electricity rate. For a device drawing 5 W for 16 hours a day at €0.28/kWh: (5 ÷ 1000) × 16 × 365 × 0.28 = €8.18/year.
How smart plugs reduce this
A smart plug on a schedule cuts power completely during hours the device does not need to be on standby. A TV that only needs standby from 6 pm to 11 pm can be powered off for the other 19 hours, eliminating 79% of standby draw from that device.
How much do standby devices actually cost? Read How Much Does Standby Power Cost?