Method. Cost = watts ÷ 1000 × hours used × your unit rate. A 2,500 W tumble dryer running one hour a day at 25 p/kWh costs 62.5 p a day, £3.94 a week and roughly £228 a year. Washing machines, dishwashers and fridge-freezers are quoted per cycle or per year because their real draw cycles up and down — the presets use typical consumption figures, which is kinder to reality than their (misleading) nameplate watts.

Worked example. Electric shower: 9,500 W × 10 minutes = 1.58 kWh ≈ 40 p at 25 p/kWh. Two showers a day is near £290 a year — four-minute showers are the single cheapest renovation you will ever make.

Standby. A 10 W router left on all year costs about £22. Modern TVs and consoles sip 1 W or less in standby (under £3 a year), so chase hours-of-use rather than climbing behind the furniture — the exception is old set-top boxes and anything warm to the touch overnight.

Edge cases. This measures electricity only, not the gas half of the bill, and it prices use, not the standing charge you pay regardless. Smart meters and £10 plug-in energy monitors give real readings for anything with a plug.

Method: unit-rate arithmetic, no estimates of your tariff. Typical-consumption presets compiled from manufacturer and energy-savings-body published figures. Not financial advice. Last reviewed 2026-09-21.