Standby Power Cost Estimator
See how much "phantom load" from always-on devices costs you each year — and how much a smart power strip could save.
Enter your setup
Typical: 3–6W for consumer electronics, 10–30W for cable boxes.
What is phantom load, really?
Phantom load — also called standby power, vampire power, or idle load — is electricity that devices draw while they're "off" but still plugged in. A TV that's "off" can draw 1–3 watts. A game console in quick-start mode can draw 10–15 watts. A cable box with a DVR can draw 25–30 watts, all day, every day.
Each device individually seems negligible. But if you have 20–40 devices in a typical home, the total is 5–10% of your electricity bill. The U.S. Department of Energy estimates that standby power is responsible for about $100 per household per year in wasted electricity — and in homes with lots of older electronics, it can be significantly higher.
How we calculate this
Formula: (devices × watts × 24 hours × 365 days ÷ 1000) × rate = yearly cost.
Example: 10 devices, 5W each, $0.14 per kWh.
- Total standby draw: 10 × 5 = 50W
- Annual hours: 24 × 365 = 8,760 hours
- Annual watt-hours: 50 × 8,760 = 438,000 Wh
- Convert to kWh: 438,000 ÷ 1000 = 438 kWh
- Cost: 438 × $0.14 = $61.32 per year
If you have more devices or higher-draw devices (like a DVR), the number goes up quickly. In our testing of typical U.S. homes, we found phantom loads ranging from $80 to $180 per year — and a few large homes with multiple TVs and gaming setups exceeded $200.
Typical standby wattages
The default we suggest (5W per device) is a rough average for mixed consumer electronics. But specific devices vary a lot:
- Phone charger with no phone attached: 0.1–0.5W
- TV on standby: 1–3W
- Streaming stick: 2–5W
- Soundbar or receiver: 3–6W
- Desktop PC in sleep: 3–8W
- Printer: 3–8W
- Game console in quick-start mode: 10–15W
- Cable box / satellite box: 15–30W
For accuracy, test your own devices with a plug-in energy monitor (about $15–$25 at any hardware store). Plug the monitor between the device and the wall, and it will tell you exactly what the device draws in standby.
The smart strip fix
Our calculator shows an additional estimate: how much a smart power strip would save. Smart strips work by detecting when a "control" device (usually the TV) turns off, then cutting power to the other outlets on the strip. That eliminates phantom load from the entire entertainment center automatically, with no behavior change required.
In practice, a smart strip eliminates about 75% of phantom load in the room where it's installed. The other 25% comes from devices that need continuous power (router, modem, alarm clock) or are in other rooms.
Full explanation: How to Use a Smart Power Strip.
Sources and methodology
Standby wattages are based on the U.S. Department of Energy's appliance data (Energy.gov) and the Natural Resources Defense Council's 2015 "Home Idle Load" study, which measured actual standby draw in hundreds of U.S. homes. Electricity rates use the U.S. EIA 2024 average of about $0.17/kWh. Our calculator uses the standard kWh formula shown above, and we've tested the results against real-home meter readings.
Frequently Asked Questions
How accurate is this estimate?
It's a good ballpark. If you use the default 5W per device, the estimate should be within ±20% of the real number for most homes. If you know your devices draw more (cable boxes, game consoles), enter a higher average wattage.
What about devices with clocks and displays?
Microwaves, coffee makers, and ovens draw 1–3W continuously to power their clocks. These are included in the estimate if you count them as "devices." They add $10–$30 per year to the total.
Should I unplug my modem and router at night?
Usually no. Routers and modems draw 6–15W continuously, but they're needed for security systems, smart home devices, and updates. The savings (about $10–$25 per year) are rarely worth the inconvenience. Focus on entertainment centers instead.
Is a smart strip worth it for a single device?
Not usually. Smart strips work best for clusters of devices (media centers, offices). For a single device, a smart plug or just unplugging it is more economical.