How much does it cost to run a immersion heater? (2026 price cap)
At the GB-average Ofgem price cap for 1 October to 31 December 2026, a immersion heater rated at 3kW costs 79p an hour to run and around £288 a year assuming 1 hour a day heating a cylinder.
Per hour
79p
Per typical use
79p
Per day
79p
Per week
£5.54
Per year
£288
Typical rating and how we worked this out
This page uses a typical rating of 3kW for a immersion heater; published figures for this appliance range from 3kW to 3.8kW. An immersion heater heats water directly in the cylinder rather than via a boiler — a straightforward, and on a standard tariff relatively expensive, way to heat water, though a well-timed top-up can beat running a boiler for a small amount of hot water. The running cost follows the same formula used across this site: watts ÷ 1,000 × hours × unit rate. Typical use is modelled as 1 hour a day heating a cylinder, which is how the per-day, per-week and per-year figures above were calculated — see the cost-to-run calculator to change the wattage, hours or region yourself.
Rate used: Ofgem price cap, 1 October to 31 December 2026, GB average electricity — 26.32p/kWh (excl. VAT, removed 1 Oct 2026–31 Mar 2027).
Cost by region
Same appliance, same use — ranked most to least expensive by region under the price cap:
| Region | Elec p/kWh | Cost per hour | Typical annual cost |
|---|---|---|---|
| Merseyside and Northern Wales | 27.86 | 84p | £305 |
| South Eastern England | 26.88 | 81p | £294 |
| Eastern England | 26.61 | 80p | £291 |
| London | 26.60 | 80p | £291 |
| South Western England | 26.58 | 80p | £291 |
| Southern Wales | 26.55 | 80p | £291 |
| North Western England | 26.49 | 79p | £290 |
| Southern England | 26.47 | 79p | £290 |
| Northern Scotland | 26.35 | 79p | £289 |
| Southern Scotland | 26.11 | 78p | £286 |
| West Midlands | 25.60 | 77p | £280 |
| Yorkshire | 25.60 | 77p | £280 |
| North Eastern England | 25.46 | 76p | £279 |
| East Midlands | 25.36 | 76p | £278 |
| Great Britain average | 26.32 | 79p | £288 |
East Midlands is cheapest at £278 a year; Merseyside and Northern Wales is most expensive at £305 a year — a gap of £27.38 for identical use.
How a immersion heater compares with similar appliances
Ranked by typical annual cost in heating & cooling, GB average:
- immersion heater — £288 a year (this page)
- infrared heating panel — £269 a year
- halogen heater — £231 a year
- electric fireplace — £346 a year
- electric fan heater (2kW) — £384 a year
- dehumidifier — £173 a year
Three practical ways to cut the cost
- Use the timer, if fitted, to heat water shortly before it is needed rather than keeping the cylinder hot all day
- Use the smaller top element for a quick top-up rather than the full-cylinder bottom element
- Improve the cylinder insulation jacket — a well-lagged cylinder holds heat for hours after the element switches off
FAQs
- How much does it cost to run a immersion heater for an hour?
- 79p at the GB-average rate (26.32p/kWh, 3kW). One typical use — 1 hour a day heating a cylinder — costs closer to 79p.
- How much does a immersion heater cost to run per year?
- Around £288 a year at the GB-average rate, assuming 1 hour a day heating a cylinder — about £5.54 a week.
- Which UK region is cheapest to run a immersion heater in?
- East Midlands, at £278 a year, against £305 in Merseyside and Northern Wales — £27.38 apart for identical use, purely from the regional rate.
- Does the exact wattage of my immersion heater change the cost much?
- Yes — ratings range 3kW–3.8kW, so the top of that range costs about 1.3x the bottom. This page uses 3kW; check your own rating plate.
- Does the October 2026 price cap affect this figure?
- Yes — figures use the Ofgem cap for 1 October to 31 December 2026. Electricity excludes VAT (removed 1 Oct 2026–31 Mar 2027); gas includes 5%. See the price cap page for the full breakdown.
Sources
- Heatable — how much energy do household appliances use — wattage and usage figures for this appliance.
- Ofgem — Energy price cap unit rates and standing charges (regional tables, read 12 September 2026).
Related
- Cost-to-run calculator and full A–Z — check any appliance or enter a custom wattage.
- Energy price cap, 1 October to 31 December 2026 — every region, every payment method.
- Back-billing calculator — if a bill for this or any appliance looks like it covers too many months.
- Free bill audit — if your overall energy costs look high regardless of any one appliance.
Send us one bill. We'll send back every overcharge — and the cheapest legitimate replacement.
Whether you run a Mayfair restaurant group or rent a flat in Salford, the audit is the same and the fee is the same: nothing, unless we save you money.