Home tech

Standby power: which devices waste the most electricity when 'off'?

By Nazrul Islam. Updated October 11, 2026.

What is standby power (phantom load or vampire power)?

Standby power is the electricity a device draws while it is plugged in but not doing its main job. People also call it phantom load, vampire power or idle load. It powers clocks, remote-control receivers, network connections, status lights and power adapters.

Most devices that turn on with a remote never fully switch off. A small circuit stays awake, waiting for the signal. Devices that “wake fast” or download updates overnight keep even more circuitry running.

Each device draws only a few watts. The problem is that it draws them 8,760 hours a year, in every room.

How much standby power does a typical US home use?

Two well-known studies give a range.

NRDC put the average cost at about $165 per household per year. Nationally, it estimated about $19 billion a year. That equals the output of about 50 large (500 MW) power plants.

The two numbers measure slightly different things. LBNL measured standby of individual devices. NRDC’s “idle load” counts everything that never turns off, including furnace controls and water recirculation pumps. The audited homes averaged 65 always-on devices each.

At today’s prices, 164 W costs more than NRDC’s 2015 figure:

164 W × 8,760 h ÷ 1,000 = 1,437 kWh a year × $0.18 = about $259 a year.

Which devices use the most power when “off”?

The table below lists measured standby draws. Most of the device data comes from LBNL measurements made in the 2000s. Newer models are often lower, so treat these as “what to check first,” not as your exact numbers.

Yearly cost uses watts × 8,760 ÷ 1,000 × $0.18. NRDC’s audit found printers ranging from 2 to 26 W and cordless phones from 1 to 12 W. It also found desktop computers costing up to $49 a year in idle mode, TVs up to $38 and cable boxes up to $30.

The pattern is clear. Pay-TV boxes, game consoles left in instant-on, and computers that never sleep are the big ones. Phone chargers with nothing attached are close to zero. One LBNL-measured charger used 0.14 W, about 22 cents a year.

NRDC’s 2011 set-top box study found a typical DVR used about 29 W “off” and 30 W “on.” Turning it off with the remote saved almost nothing.

How do you calculate the yearly cost of standby power?

Use this formula:

Yearly cost = standby watts × 8,760 ÷ 1,000 × price per kWh

8,760 is the number of hours in a year. Dividing by 1,000 converts watt-hours to kilowatt-hours. The EIA expects the 2026 US average residential price to be about 18.2¢/kWh. Check your bill for your own rate.

A handy rule: each watt left on all year costs about $1.58 at 18¢. A 20 W cable box and console setup is about $32 a year.

How do you measure standby power at home?

Plug-in watt meter. Plug the meter into the wall and the device into the meter. Switch the device “off” the normal way, wait a minute, and read the watts.

Tips for good readings:

• As a rule of thumb, pick a meter that displays tenths of a watt. Readings under 1 W from cheap meters are rough.
• Measure a whole entertainment center at once by plugging its power strip into the meter.
• Watch for a few minutes. Some boxes spike when they download updates.
• LBNL notes most consumer meters cannot safely handle more than about 1,300 W. Do not use one on a space heater or other high-wattage appliance. See what it costs to run a space heater instead.

Whole-house reading. If your utility shows hourly smart meter data, look at the lowest hour of the night. LBNL suggests around 3 a.m. when the refrigerator compressor is likely off. That baseline is roughly your always-on load. Night lights, fans or pumps can inflate it.

Smart plugs with energy monitoring also work. Leave one on a device for a day to see its off-hours draw.

What should you unplug, and what should you leave on?

Worth cutting:

• Game consoles. Switch to the shutdown or energy-saving mode. On an Xbox Series X, that drops standby from 10-15 W to about 0.5 W. That saves roughly $15 to $23 a year at 18¢.
• Smart TV wake features. NRDC found “smart wake” or Quick Start raised standby from 0.6 W to about 12.5 W. Its model showed a TV’s yearly use jumping from 108 to 191 kWh. Turn these off unless you use voice or cast wake-up.
• Computer power settings. ENERGY STAR recommends display sleep after 15 minutes and computer sleep after 30. It says power management features can save a home office $15 per year.
• Rarely used gear. Guest-room TVs, second consoles, old stereos, printers you use monthly and spare chargers.

Leave on:

• Refrigerators, freezers, sump pumps and well pumps. These are not standby loads. Cutting them causes real damage. See how many watts a refrigerator uses.
• Medical equipment, such as CPAP machines, oxygen concentrators and anything a doctor prescribed.
• Smoke and CO alarms, security systems and furnace or boiler controls. Never cut power to safety devices.
• Your router and modem, unless you accept losing the internet, smart home devices and remote alerts while it is off.
• Cable or satellite DVRs that record shows or need overnight guide updates. Cutting power can cause long reboots and missed recordings.
• Devices with clocks you depend on, unless you are happy resetting them.

Microwaves made since 2016 are limited to 1 W of standby (about $1.58 a year at 18¢); older ones measured around 3 W (about $5). Unplugging one may not be worth the hassle.

Do smart power strips and smart plugs save money?

Smart (advanced) power strips cut power to some outlets when the main device is not in use. A typical home version has a “control” outlet for the TV or computer. When the TV turns off, the strip cuts the soundbar, console and player plugged into the “switched” outlets. Keep the DVR, router and anything that needs updates on the “always on” outlets. Savings vary by product and by how you use it.

Smart plugs let you schedule or remotely switch a device off. But the plug draws power itself. Shelly lists its Plug US at under 1 W of self-consumption. At 1 W, that is about $1.58 a year at 18¢. A smart plug on a 0.5 W device costs more than it saves. Use one only where the device draws several watts.

A simple switched power strip works too. It costs nothing to run and cuts everything at once.

Safety notes:

• Do not plug a power strip into another power strip (“daisy-chaining”).
• Plug space heaters directly into a wall outlet, never a power strip or smart plug.
• Replace any strip or plug that feels hot, smells burnt or has a damaged cord.

Are there federal limits on standby power?

Some limits exist, but not one rule for every device.

These rules explain why newer chargers and microwaves draw so little. They do not cover set-top boxes, consoles or “network standby” features like smart TV wake. That is where most waste now hides.

During an outage, unplug idle gear to stretch a portable power station, since a 20 W cable box alone drains 480 Wh a day.

Quick answers

Does a TV use electricity when turned off? Usually under 1 W. NRDC measured an average 0.6 W. With smart wake or Quick Start on, many smart TVs draw 5 to 20 W.

What is the biggest energy vampire in a home? In older measurements (LBNL 2000s, NRDC 2011), cable and satellite boxes with DVRs drew about 15 to 45 W even when “off”; newer boxes are often lower. Game consoles in instant-on mode and desktops that never sleep come next.

How much money does unplugging everything save? NRDC estimated $165 a year for the average home in 2015. You cannot cut all of that, since some loads must stay on. Cutting 20 W saves about $32 a year at 18¢.

Is it safe to unplug my router every night? It is safe, but you lose Wi-Fi calling, security cameras and smart alarms while it is off. Most people should leave it on.