What your appliances actually cost to run
Guide · updated 2026-08-23
Every running cost is the same sum: kilowatts × hours × your unit rate. The hard part is knowing the kilowatts, so here they are.
The sum
Power in watts, divided by 1,000, multiplied by hours of use, gives kWh. Multiply by your unit rate in pence and you have the cost. A 3 kW kettle boiling for three minutes uses 3 × 0.05 = 0.15 kWh — under 5p at most rates.
The wattage is on the rating plate, usually on the back or inside the door. Where a thermostat cycles the appliance on and off — fridges, heaters, ovens — the plate gives the peak, not the average, so the figures below are per typical use instead.
Typical energy per use
- Kettle — about 0.1-0.15 kWh per boil. Roughly 5p a day for a heavy tea drinker.
- Electric oven — 1-2 kWh an hour. A Sunday roast is one of the larger single items in a week.
- Electric shower (8.5-10.5 kW) — around 1.5 kWh for a ten-minute shower, and it is one of the biggest instantaneous loads in a house.
- Washing machine — 0.5-1 kWh a cycle; a 30°C wash uses roughly half what a 60°C one does, because almost all of it is heating water.
- Tumble dryer — 2-4 kWh a cycle for a vented or condenser model, around 1-1.5 kWh for a heat pump dryer. Usually the single most expensive appliance in the house per use.
- Dishwasher — 1-1.5 kWh a cycle, again mostly water heating.
- Fridge freezer — 0.5-1.5 kWh a day, running continuously.
- Fan heater (2 kW) — 2 kWh an hour. Cheap to buy, expensive to run, and the classic winter bill shock.
- Air source heat pump — very roughly 5-15 kWh a day in winter for a typical house, depending on insulation and weather.
- Electric car — 3-4 miles per kWh, so around 10-13 kWh per 40 miles driven.
Standby is mostly a myth now
Modern appliances draw around 0.5-2 W on standby, thanks to regulation. A house full of them might total 20-40 W — perhaps £30-£60 a year, and worth a plug strip, but nothing like the tumble dryer. Old set-top boxes and some games consoles in rest mode are the real exceptions and can pull 10-20 W each.
Costing it at your own rate
Multiply any figure above by your unit rate. On a half-hourly tariff that rate depends on when you run it, which is where the savings are — see the cheapest time to use electricity. For your actual live rate, check prices for your region.
Common questions
What is the most expensive appliance to run?
Per use, a tumble dryer at 2-4 kWh a cycle. Over a year, electric heating dwarfs everything else in a home that has it.
How much does it cost to boil a kettle?
About 0.1-0.15 kWh, so a few pence at typical unit rates. Boiling only what you need is the entire saving available.
Does leaving things on standby waste much electricity?
Far less than it used to. Most modern devices draw 0.5-2 W, adding up to perhaps £30-£60 a year across a whole house. Old set-top boxes are the notable exception.
See it on your own numbers. halfhourly.uk shows live half-hourly prices for every GB region for free, and if you connect an Octopus account it prices your own smart-meter readings against every tariff.