What is phantom load or vampire energy?

Phantom load (also called standby power or vampire energy) is the electricity consumed by devices when they are switched off but still plugged in. TVs, cable boxes, chargers, and microwaves all draw power continuously from the outlet even when not in active use.

Standby Power Calculator

How much is phantom load costing you? Check the devices in your home to calculate your always-on electricity waste.

How to Use This Calculator

Check the devices in your home

Check the boxes for every device in your home that stays plugged in — even when "off." These always-on loads are called phantom load or "vampire energy." The checklist uses real standby wattage values from product testing data. Adjust the quantity using + and − buttons for devices you own multiple of (TVs, phone chargers, etc.).

Uncheck devices you don't have

Uncheck anything you don't own. The pre-checked defaults represent a typical American home. If you have solar monitoring hardware, smart home hubs, or other always-on devices, add their wattage mentally — this calculator covers the most common phantom loads.

See where the waste is

The result shows your total always-on wattage, annual kWh wasted, and annual cost. The "Top offenders" section identifies the three biggest contributors so you know where to focus — often a cable box or DVR is responsible for a surprising fraction of the total.

The Formula

Total standby watts = ∑ (Device standby W × Quantity) Daily kWh = Total watts × 24 hrs ÷ 1,000 Annual kWh = Daily kWh × 365 Annual cost ($) = Annual kWh × Electricity rate

Standby power is measured at the device's lowest power state while still plugged in (often called "standby mode," "soft-off," or idle). The values here come from product testing by ENERGY STAR, LBNL (Lawrence Berkeley National Laboratory), and the EU's Ecodesign directive measurement program.

The 24-hour factor is key: phantom loads run continuously — 8,760 hours per year. A device drawing just 5W contributes 43.8 kWh/year and costs $6.57 at average US rates. Not much alone, but 10 such devices = $65.70/year of pure waste.

Example

Typical US home — surprising standby costs

An average US home with a cable box, router, two TVs, a microwave, coffee maker, desktop computer, and three phone chargers has this phantom load profile:

Cable/satellite box15W

Router/modem10W

2× LED TV1W

Microwave3W

Coffee maker1.5W

Desktop computer6W

3× phone charger0.9W

Result

Total standby load37.4W

Annual kWh wasted327 kWh

Annual cost$49/year

Top offenderCable box (15W = $20/yr)

The US Department of Energy estimates the average home spends $100-200 per year on standby power — roughly 5-10% of the total electricity bill. Using smart power strips and unplugging unused chargers can eliminate a significant fraction of this waste without sacrificing convenience.

FAQ

What uses the most standby power in a typical home? ▼

The worst offenders in most homes are: cable/satellite boxes (15-25W, often left on 24/7 even when not recording), DVRs (10-20W), game consoles (5-15W in standby, much more in "instant on" mode — a PlayStation 5 in rest mode uses ~1.3W, Xbox Series X ~13W), routers and modems (8-15W, but these provide useful service so unplugging them makes less sense), and desktop computers in sleep mode (5-10W).

What can I do to reduce phantom load? ▼

The most effective steps: (1) Use a smart power strip for entertainment centers — when the TV turns off, it automatically cuts power to the cable box, game console, and speakers. (2) Unplug chargers when not charging — they still draw power when idle. (3) Replace your cable box with a streaming stick if you don't record — modern Fire TV/Roku sticks use 2-4W while streaming vs 15-25W for a cable box. (4) Enable deep sleep mode on computers and game consoles. (5) Use the Energy Monitor on your electricity meter or a plug-in power meter (Kill-A-Watt) to identify other hidden loads.

Do solar panels help with standby power costs? ▼

Yes — solar panels offset your total electricity consumption including phantom loads. However, standby loads typically run 24/7, while solar panels only produce during daytime. Without battery storage, nighttime phantom loads are still grid-powered. The smartest approach is to reduce phantom loads first (free savings), then size your solar system based on the remaining consumption. Every 100 kWh/year reduction in phantom load is one less panel you need to buy.

Why does a cable box use so much power? ▼

Cable and satellite boxes have historically used enormous standby power (15-25W) because they stay powered to receive updates, maintain the electronic program guide, and enable instant-on. The ENERGY STAR specification pushed manufacturers to reduce this, and newer X1/Flex boxes from Comcast draw about 12W. Still, at 24/7 operation, even 12W = 105 kWh/year = $16 at average US rates. Many homes with 2-3 boxes spend $30-50/year just on set-top box standby power.