How this is worked out
Energy used in kWh = watts ÷ 1,000 × hours. Cost = kWh × unit rate. We then scale up to a week, a month and a year (52 weeks).
The default unit rate is Ofgem’s price cap for 1 October to 31 December 2026: 26.32p per kWh for electricity, the average for England, Scotland and Wales paying by Direct Debit. The standing charge of 54.83p a day is paid whatever you use, so it isn’t included.
Typical running costs
These use the price cap rate and a typical wattage. Your appliance may differ, so check its rating plate.
| Appliance | Power | Cost per hour |
|---|---|---|
| Oil-filled radiator on full | 2,000W | 52.6p |
| Fan heater | 3,000W | 79.0p |
| Electric blanket | 100W | 2.6p |
| Dehumidifier | 250W | 6.6p |
| Tumble dryer (vented) | 2,500W | 65.8p |
| TV (55in LED) | 100W | 2.6p |
| Air fryer | 1,500W | 39.5p |
Heaters and dryers with thermostats or sensors cycle on and off, so the real cost is often lower than running at full power the whole time.
Worked example
A 2kW oil-filled radiator used for 3 hours a day, every day: 2 × 3 = 6 kWh a day. At 26.32p that’s £1.58 a day, or about £575 a year if you used it every day of the year.
Questions people ask
How much does it cost to run a 2kW heater for an hour?
A 2kW heater uses 2 kWh an hour. At the price cap unit rate of 26.32p per kWh (1 October to 31 December 2026), that’s about 53p an hour.
How do I find an appliance’s wattage?
Look for the rating plate on the back or underneath, or in the manual. It’s given in watts (W) or kilowatts (kW). For appliances that cycle on and off, like fridges, the yearly kWh figure on the energy label is a better guide.
Why is my real bill different?
Your own tariff may be cheaper or dearer than the price cap average, rates vary by region, and many appliances don’t draw full power all the time. Your bill also includes a daily standing charge, which this calculator leaves out.
What is the energy price cap?
It’s the maximum Ofgem allows suppliers to charge per unit and per day on standard variable tariffs. It changes every three months, on 1 January, 1 April, 1 July and 1 October.
Sources
Trade review pending. A named tradesperson will check this calculator, and their name and qualifications will appear here.
Figures last checked 25 October 2026. Read how we calculate and our disclaimer. Found a mistake? Tell us.