The one formula you need
Every electricity bill comes down to kilowatt-hours (kWh): one kWh is a 1,000 W appliance running for one hour. Unit rates depend on your supplier, region and tariff, so check your bill. The examples below use 25p per kWh, close to the Ofgem price cap in recent years.
Cost = watts ÷ 1,000 × hours used × price per kWh.
Typical costs at 25p per kWh
- Kettle (3 kW), boiled for 3 minutes five times a day: about 19p a day, or £5.60 a month. Boil only what you need. See our kettle picks.
- Vented tumble dryer: around 4 to 5 kWh a load, so about £1.10. A heat pump dryer uses about a third of that.
- Heated airer (about 300 W) for 6 hours: about 45p a load. See our heated airer picks.
- Compressor dehumidifier (about 200 W) for 8 hours: about 40p a day. Our dehumidifier list shows the wattage of each model.
- Air fryer (1.5 kW) for 20 minutes: about 13p a meal. Our air fryer picks start under £100.
- Fan heater (2 kW): 50p an hour.
Where the money goes
Anything that heats is expensive: tumble dryers, heaters, ovens, kettles, immersion heaters and electric showers. Phones, routers, smart speakers and LED bulbs are small change by comparison, so do not lose sleep over chargers left plugged in.
Cheapest ways to cut the bill
- Dry laundry on a heated airer with a dehumidifier in the same room instead of using a vented dryer.
- Use the air fryer or microwave for small meals rather than heating a full oven.
- Heat the person, not the room: a heated throw or a short burst of a fan heater in one room costs less than heating an empty house.
- Check your tariff: Economy 7 or a smart tariff can make overnight dishwasher and laundry cycles much cheaper.
Buy for the bill, not just the price
A cheaper appliance that uses more energy can cost more within a couple of winters. On Buyrskip every product shows its usual price and key specs, including power use where it matters, so you can compare the full cost of owning it, not just the price on the day.
Frequently asked questions
How do I work out the running cost of an appliance?
Divide the wattage by 1,000, multiply by the hours you use it and by your price per kWh. A 2,000 W heater used for 2 hours: 2 × 2 × 25p = £1.
What price per kWh should I use?
The unit rate on your latest bill. Under the Ofgem price cap it has been roughly 25p to 28p per kWh for electricity in recent years, but fixed tariffs, Economy 7 and smart tariffs differ.
Is an air fryer cheaper than an oven?
Usually, for small portions. A 1,500 W air fryer cooking for 20 minutes uses about 0.5 kWh (about 13p), while heating a large electric oven for the same meal often uses two to three times as much.
Are dehumidifiers expensive to run?
A compressor dehumidifier of about 200 W running 8 hours costs about 40p a day. Desiccant models use more power, but give off warmth, which helps in cold rooms.