Phantom Power: Devices That Use Electricity When Off

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Walk through your house at night with the lights off and count the little glows: the red dot on the TV, the clock on the microwave, the green light on the cable box, the charger blinking by the bed, the console in “rest mode.” Every one of them is drawing a bit of power while everyone sleeps. That’s phantom power, and in some homes it adds up to real money.

The short answer: phantom power, also called standby power or vampire load, is the electricity devices use when they’re switched off or not doing their main job. Lawrence Berkeley National Laboratory puts it at about 5–10% of home electricity in typical U.S. homes. Most single devices draw under a watt; a few, like cable boxes, draw much more and are worth tackling first.

What phantom power is, and why devices use it

Berkeley Lab, which has studied standby power for more than two decades, defines it as electricity consumed by devices when they are switched off or not performing their primary function. Some of it does a real job: listening for the remote, keeping a clock, staying on the network, charging a battery, keeping a fridge’s controls awake. Some of it is just poor design. The lab’s rule of thumb is that almost anything with an external power adapter, a battery, a remote, a display or light, or a constant network connection draws power around the clock.

The good news: standby power per device has fallen a lot. Berkeley Lab says typical products drew 1–3 watts in standby twenty years ago and are probably near 0.5 watts now. The bad news: we own far more of them, many connected to Wi-Fi.

How much does phantom power cost?

Here’s the easy math from Berkeley Lab: one watt running all year is about 9 kWh. At the U.S. average residential price of 18.31 cents per kWh (EIA, July 2026), that’s about $1.60 a year per watt. So:

• A phone charger at 0.5 W: about 80 cents a year.
• A cable box at 8 W: about $13 a year.
• A house with 50 W always on: about 440 kWh, or $80 a year.

Those are our estimates at the national average price; use your own rate from your bill. Field studies show how wide homes vary. In a 2015 report, NRDC, with Home Energy Analytics and a Stanford lab, analyzed smart meter data from 70,000 northern California homes and found an average always-on load of 164 watts, about 1,300 kWh a year and 23% of those homes’ electricity. That figure is broader than standby alone: it counts everything that never shuts off, including recirculation pumps, aquarium gear and devices left fully on. NRDC estimated that idle load costs about $165 per U.S. household a year at the national average price at the time.

Which devices use the most standby power

Berkeley Lab keeps a table of measured standby power for common products, compiled from studies and lab tests. Here are the medians and the highest readings, with what a year costs at the median by our math.

Device	Median standby (W)	Highest measured (W)	Median cost per year
Uninterruptible power supply (UPS)	25.5	26	About $41
Cable or satellite set-top box	8	30	About $13
Water heater controls	7.8	12	About $13
VCR	7.4	12	About $12
Security system	6.6	8.2	About $11
Stereo	4	27	About $6
Room air conditioner	4	10	About $6
Rice cooker	3.7	8	About $6
Security camera	3.5	9.4	About $6
Internet gear (modem, router)	3.3	8	About $5
Desktop computer	2.7	15	About $4
Printer	2.6	9.1	About $4
Game console	1.7	24.5	About $3
Microwave	1.5	7	About $2
Television	0.95	23.8	About $1.50
Phone/electronics charger (nothing attached)	0.52	1.9	About $0.80
Smart plug (its own draw)	0.25	1.43	About $0.40

The “highest” column matters. A median TV sips under a watt, but the hungriest TV in the data drew almost 24 W, and the top game console 24.5 W, roughly $38–39 a year each by our math. Consoles left in an “instant-on” or quick-resume mode are a common reason. Some always-on loads you shouldn’t touch, like smoke and CO alarms, GFCI outlets and the fridge.

How to find your own phantom load

1. Look at 3 a.m. The Department of Energy suggests checking your hourly smart meter data in your utility’s app: your use at 3 a.m. should be well below your use at 7 p.m. The lowest steady hour is roughly your always-on load, plus the fridge and anything else cycling.
2. Measure suspects with a plug-in meter. Plug the meter into the wall and the device into the meter, switch the device off, and read the watts. Berkeley Lab says such meters cost under $50, and some libraries lend them.
3. Go room by room. The TV corner and the home office usually hold the most: TV, sound bar, cable box, console, computer, monitors, printer, speakers.
4. Check the garage and basement. An old second fridge, a dehumidifier, a hot water recirculation pump or a UPS with nothing plugged into it can draw more than everything else combined.

What to unplug, and what to leave alone

Berkeley Lab’s own “what can I unplug now?” list starts with old devices you rarely or never use and seasonal ones that sit idle for months. Good candidates, from that list:

• The TV, set-top box and sound bar in the guest room.
• Old VCRs, DVD players, boom boxes and rarely used audio gear.
• Chargers with nothing attached, and e-bike or golf cart chargers in the off-season.
• Kitchen gadgets you use now and then: rice cookers, multicookers, bread makers.
• Rarely used scanners, shredders and old printers.
• A UPS with nothing connected to it.
• Seasonal gear: window AC units, humidifiers, dehumidifiers and air filters when the season ends.

Other fixes need a setting, not a plug: turn on sleep mode on computers, put a hot water recirculation pump on a timer, switch off the hot or cold side of a water dispenser you don’t use, and turn off a heated toilet seat in summer. Leave alone anything that protects you or your food: smoke and CO alarms, the fridge and freezer, a sump pump, medical equipment, and your router if anyone works from home or relies on a security system. Berkeley Lab adds a safety note: don’t keep plugging and unplugging devices with worn cords.

Power strips, smart plugs and timers

Unplugging behind the TV every night doesn’t last. Tools that make it automatic do:

• A switched power strip cuts a whole cluster, like the TV corner or the office, with one click. Berkeley Lab recommends it for groups of computer or video gear. The Department of Energy also points to advanced power strips, which turn the extras off when the main device (say, the TV) goes off.
• Smart plugs with energy monitoring show what a device draws in an app and can switch it off on a schedule. They draw a little themselves (Berkeley Lab’s median is 0.25 W), so use them on loads bigger than that: a console, a printer, a cable box you don’t record on.
• Timers fit pumps and other gear that should run only at set hours.

Be realistic. Berkeley Lab says limited research suggests an informed, aggressive approach can cut standby use by about 20%, and that most single fixes save less than a watt. Phantom power is worth an evening, not a weekend. If you want bigger savings, heating, cooling and hot water matter far more; see what uses the most electricity. And ignore any gadget that claims to stop “vampire power” or “clean” your electricity to cut the bill by half: see electricity-saving device scams.

Tools for finding and cutting phantom power

Prices change often. The prices below are what we saw at the maker or a major retailer in October 2026; check the current price before you buy.

The Kill A Watt P4400 (about $33 on the maker’s store) is the simplest tool: no app, no account, just watts and kWh on a screen. The Kasa KP125M shows live and historical use in the Kasa app, can switch a device off on a schedule, and works with Apple Home, Alexa and Google Home through Matter. The Emporia smart plug (about $34.99 on sale at Emporia) is rated 10 amps continuous, lower than most, and Emporia says not to use it for refrigerators, freezers, medical or critical network gear. The Emporia Vue 3 (about $199.99 with 16 sensors at Emporia) shows your whole home’s lowest overnight draw and every circuit; it installs in your breaker panel, a job for a licensed electrician for most people.

Check the Kill A Watt P4400 price on Amazon

Check the Kasa KP125M price on Amazon

Keep exploring

Start with our how to lower your electric bill plan, then compare energy monitoring smart plugs and whole-home energy monitors. If your plan charges more in the evening, read time-of-use rates explained. Watts and kilowatt-hours are explained in electrical energy, and more tips are in the energy saving tips category.

Phantom power questions

Does unplugging things really save money?

Yes, but usually a little. Each watt you stop wasting saves about $1.60 a year at the July 2026 U.S. average price, by our math. Unplugging a cable box you don’t use (Berkeley Lab’s median is 8 W) saves about $13 a year; unplugging a phone charger saves under a dollar. Start with the big standby users and the old second fridge.

Do phone chargers use electricity when nothing is plugged in?

A little. Berkeley Lab’s measured median for electronics chargers with nothing attached is about half a watt, roughly 4–5 kWh a year. That’s well under a dollar, so unplug them for tidiness or safety rather than savings. Old, warm “brick” adapters tend to waste more than newer ones.

Does a TV use power when it’s off?

Yes. Berkeley Lab’s median TV in standby uses just under 1 watt, but the highest reading in its data was nearly 24 W. Quick-start or “instant on” settings and the boxes around the TV, like cable boxes, sound bars and consoles, usually waste more than the TV itself. Turning off quick-start modes in the settings helps.

How much of my bill is phantom power?

Berkeley Lab puts standby at about 5–10% of home electricity in typical U.S. homes. NRDC’s study of 70,000 California homes found an average always-on load of 164 watts, 23% of their electricity, but that counts everything that never turns off. Check your own lowest overnight hour in your utility’s app to see where you stand.

Are smart plugs worth it for phantom power?

For devices that waste a few watts or more, yes. A smart plug uses about a quarter of a watt itself by Berkeley Lab’s median, so it pays off on a console, printer or set-top box, not on a phone charger. An energy-monitoring plug also shows you what the device really draws, which is the best reason to own one.

Is it safe to leave things plugged in?

For normal, undamaged devices, yes; that’s how they’re designed to be used. Replace or unplug anything with a frayed cord or a hot, damaged adapter, and don’t overload power strips. Never unplug smoke or CO alarms, the fridge, a sump pump or medical equipment to save power.