Do Smart Plugs Use Electricity When Not in Use? (Standby Cost)
By Marlo Strydom · Updated
Do smart plugs use electricity when not in use? Yes, a powered smart plug draws some electricity even when its controlled outlet is off. Whether it saves money depends on how much power it stops the connected device from using.
That small draw matters when you compare the plug with the device it controls. A smart plug only saves energy when the power it cuts from the connected device is greater than the plug's own standby use.
What Standby Use Means for Your Bill
- A connected plug needs power for its radio, control chip, and status light.
- ENERGY STAR limits qualifying smart plugs in home energy systems to 1 watt of standby power.
- Use your utility rate and the plug's measured wattage to calculate the real yearly cost.
- Schedule devices only when the avoided standby use is higher than the plug's own draw.
Why a Smart Plug Uses Power While Off
The word "off" only describes the outlet controlled by the relay. The plug's radio and control chip stay awake so they can receive the next command. Some models also power a status light or energy meter.
The Department of Energy calls electricity used by a device that appears off standby power. The same idea applies to the plug and to many devices connected through it.
How to Calculate the Yearly Cost
Check the product specifications or measure the plug with a power meter. Multiply its watts by 8.76 to get yearly kilowatt-hours. Then multiply that result by the price your utility charges per kilowatt-hour.
| Standby draw | Energy per year | Cost at $0.15 per kWh |
|---|---|---|
| 0.3 watts | 2.63 kWh | $0.39 |
| 0.5 watts | 4.38 kWh | $0.66 |
| 1.0 watt | 8.76 kWh | $1.31 |
| 1.5 watts | 13.14 kWh | $1.97 |
The table uses an example rate, not a national average. Replace $0.15 with the rate on your own bill.
When a Smart Plug Saves More Than It Uses
Compare the plug's full-day standby use with the power it cuts from the connected device. For example, a 1-watt plug uses 8.76 kWh per year. If it removes a 5-watt standby load for 12 hours each day, it avoids 21.9 kWh. After subtracting the plug's use, the net reduction is about 13.14 kWh per year.
Savings are not automatic. A lamp with a true zero-watt off state may cost more to control with a smart plug. A game console, TV, or audio system may save energy, but only a meter or reliable specification can show how much.
Devices That Should Stay Powered
Do not cut power to a refrigerator, medical device, security system, router, recorder, or any device that must stay online. Some electronics also need standby power for updates, recordings, clocks, or safe shutdowns. Check the manual before putting any appliance on a schedule. A smart fridge can keep cooling without WiFi, but it still needs electrical power.
Three Ways to Get a Useful Result
- Measure first: Record the device's off-state draw and the plug's own draw.
- Use a real schedule: Count only the hours when the device can safely be disconnected.
- Check the load rating: Keep the connected device within the smart plug's voltage, amperage, wattage, and load-type limits.
Estimate Your Smart Plug Savings
- Energy Savings Calculator: estimate annual savings with your local electricity rate.
Related Guides
- Can a Smart Plug Turn On a Kettle? (Safety & Wattage)
- Do Smart Bulb Schedules Work Without Internet?
Useful Tools and References
- Smart Home Cost Estimator - Budget for devices, hubs, installation, and monthly plans.