What is standby or vampire power?

Standby power is the electricity a device draws while switched off or idle but still plugged in — keeping a remote sensor, clock, or network connection alive. It is also called vampire or phantom load and can quietly add up to a noticeable share of a home's bill.

How much can standby cost a year?

A typical home wastes around 50 to 100 kWh a year on standby across all its devices, often 15 to 30 in cost. Homes with many set-top boxes, consoles, and chargers left on can waste considerably more.

Which devices waste the most on standby?

Set-top boxes, games consoles in rest mode, and older AV equipment are usually the worst, drawing several watts continuously. Broadband routers also run 24/7 but are often left on deliberately, so the biggest easy wins are entertainment devices.

Where do the wattage figures come from?

The per-device standby figures are typical measured averages from energy-efficiency studies. Modern appliances meeting the EU one-watt standby rule draw less, while older or feature-rich devices draw more, so treat the totals as a representative estimate.

How do I cut standby waste?

Use a switched power strip to turn off clusters of AV devices at once, enable the deepest sleep mode on consoles, and unplug chargers when not in use. Routers you may choose to leave on, but everything else can usually be switched off overnight.

Standby Power Waste Calculator

This calculator adds up the hidden cost of devices left on standby. You tick the appliances that stay plugged in and idle in your home, enter your tariff, and it returns the total annual standby energy, its cost and CO2e, and points out the single worst offender to switch off first.

How it works

Standby power is drawn continuously, so each device’s yearly energy is its watts multiplied by all 8,760 hours in a year. Summing across devices and converting gives the totals:

kWh_device = standby_watts / 1000 × 8760
total_kWh  = Σ kWh_device
cost       = total_kWh × tariff_per_kWh
co2        = total_kWh × grid_factor (≈0.21 kgCO2e/kWh)

Because the draw runs every hour of the year, even a device pulling just a few watts on standby quietly consumes tens of kilowatt-hours annually.

Tips and example

A home leaving a TV, set-top box, games console, router, and printer on standby typically wastes around 130 kWh a year — roughly 32 in cost and 27 kg of CO2. The set-top box and console usually dominate. A single switched power strip on the entertainment cluster, flicked off overnight, eliminates most of that waste with no loss of convenience.