How much does it cost to run an immersion heater?
An immersion heater with a typical power of 3,000 watts costs 79p an hour at the current price cap.
Uses Ofgem's price cap for 1 October to 31 December 2026: 26.32p per kWh, the average for Great Britain when paying by Direct Debit. Prices checked 13 November 2026.
Result
An immersion heater (3,000 W) costs 79p an hour to run at the price cap rate of 26.32p per kWh.
an hour, to the nearest penny
| A day | 79p |
|---|---|
| A week | £5.53 |
| A month | £24.02 |
| A year | £288.20 |
| Electricity used in a year | 1,095 kWh |
That is 44% of the 2,500 kWh a typical home uses in a year.
Show the workings
| Step | Sum | Answer |
|---|---|---|
| Turn watts into kilowatts | 3,000 W ÷ 1,000 | 3 kW |
| Cost of one hour | 3 kWh × 26.32p per kWh | 79p |
| Cost of one day's use | 79p × 1 hours | 79p |
| Cost of one week | 79p × 7 days | £5.53 |
| Cost of one year | £5.53 ÷ 7 × 365 days | £288.20 |
What this leaves out or assumes
- The standing charge is left out, because you pay it whether or not you use this appliance.
- A month is one twelfth of a year.
- The appliance draws its full power for the whole time it is on.
Where the figures come from
- Electricity unit rate, price cap, Great Britain average, Direct Debit: 26.32p per kWh. Source: Ofgem: Energy price cap unit rates and standing charges. Checked 13 November 2026.
- Typical yearly electricity use, medium user: 2,500 kWh a year. Source: Ofgem: Review of typical domestic consumption values, decision (Table 1). Checked 13 November 2026.
Typical power for an immersion heater is from Centre for Sustainable Energy: How much electricity am I using?. Yours may differ: check its rating plate.
Cost by how long it runs
| Running for | Electricity used | Cost |
|---|---|---|
| 5 minutes | 0.25 kWh | 6.6p |
| 10 minutes | 0.5 kWh | 13.2p |
| 30 minutes | 1.5 kWh | 39.5p |
| 1 hour | 3 kWh | 79p |
| 2 hours | 6 kWh | £1.58 |
| 4 hours | 12 kWh | £3.16 |
| 8 hours | 24 kWh | £6.32 |
| 24 hours | 72 kWh | £18.95 |
Cost over a month and a year
If you used it this much every day:
| Used for | A month | A year |
|---|---|---|
| 30 minutes a day | £12.01 | £144.10 |
| 1 hour a day | £24.02 | £288.20 |
| 2 hours a day | £48.03 | £576.41 |
| 4 hours a day | £96.07 | £1,153 |
| 8 hours a day | £192.14 | £2,306 |
| All day, every day | £576.41 | £6,917 |
How much electricity does an immersion heater use?
An immersion heater rated at 3,000 watts uses 3 kWh of electricity for every hour it draws full power. Used for 1 hour every day, that is 1,095 kWh a year, 44% of the 2,500 kWh a typical home uses.
Cost in your region
The price cap is different in each region. Running an immersion heater for an hour costs 76.1p in East Midlands, the cheapest region, and 83.6p in Merseyside and Northern Wales, the dearest.
| Region | Price per kWh | Cost for an hour |
|---|---|---|
| East Midlands | 25.36p | 76.1p |
| Eastern England | 26.61p | 79.8p |
| London | 26.60p | 79.8p |
| Merseyside and Northern Wales | 27.86p | 83.6p |
| North Eastern England | 25.46p | 76.4p |
| North Western England | 26.49p | 79.5p |
| Northern Scotland | 26.35p | 79.1p |
| South Eastern England | 26.88p | 80.6p |
| South Western England | 26.58p | 79.7p |
| Southern England | 26.47p | 79.4p |
| Southern Scotland | 26.11p | 78.3p |
| Southern Wales | 26.55p | 79.7p |
| West Midlands | 25.60p | 76.8p |
| Yorkshire | 25.60p | 76.8p |
Paying by Direct Debit. Prices for other ways of paying.
How it compares
| Appliance | Typical power | An hour |
|---|---|---|
| Electric shower | 9,000 W | £2.37 |
| Immersion heater | 3,000 W | 79p |
| Electric heater | 2,500 W | 65.8p |
| Oil-filled radiator | 2,000 W | 52.6p |
| Dehumidifier | 500 W | 13.2p |
| Towel rail | 450 W | 11.8p |
| Heating blanket | 150 W | 3.9p |
Running costs of every appliance
Checking your own immersion heater
3,000 watts is a typical figure. Yours may be higher or lower. Look for the rating plate on the back or underside, find the number followed by W or kW, and put it in the calculator above.
Typical power is from Centre for Sustainable Energy: How much electricity am I using?, checked 13 November 2026. Prices are from Ofgem: Energy price cap unit rates and standing charges. The costs are our own sums.