Heating, cost per hour
2kW electric heater: cost per hour, per evening and per winter
A fan heater, an oil filled radiator, a convector and a halogen heater sold as a '2kW heater' all draw the same 2kW when they are working at full output. They still cost noticeably different amounts to run, and the reason has nothing to do with the wattage printed on the box. It is how much of the time each one is actually pulling that power.
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All four draw 2kW; only the duty cycle differs
A halogen heater and a fan heater usually have no thermostat, so both draw their rated power for as long as they are switched on. An oil filled radiator and a convector do have a thermostat and cycle off once the room is warm, and the convector, with far less metal to heat, reacts faster and ends up cycling on more often across an hour than the slower, heavier radiator. Same 2kW written on every box; four different average draws, depending on what fraction of the hour each one is actually pulling that power.
| Option | Running | Cost per hour | Relative |
|---|---|---|---|
| Halogen heaterone 1kW bar, no thermostat | 26.3p | 28.5p | |
| Oil filled radiator2kW rated, thermostat, slow to react | 31.6p | 33.5p | |
| Convector heater2kW rated, thermostat, quick to react | 36.8p | 39.7p | |
| Fan heater2kW rated, no thermostat, runs flat out | 52.6p | 54.7p | |
| Gas central heatingwhole house, not one room | 95.6p | £1.31 |
The halogen heater works out at 28.5p an hour and the gas central heating at £1.31, a factor of 4.6. Run any of the four electric heaters for a typical 300 hours across a heating season and the gap between the cheapest and dearest of them alone is worth about £308.
What an evening and a winter actually cost
A fan heater run flat out for a four hour evening comes to about £2.11 in electricity, and left on for four hours a day across a roughly 120 day UK heating season that adds up to about £252.67. The same evening on a thermostatted convector is about £1.47, and the same winter about £176.87. A halogen heater run on one bar is the cheapest of the four across a winter at about £126.34, but only because it is heating you directly rather than the room.
Where the working comes from
The purchase price barely moves any of these numbers; even the dearest heater here pays for itself in a few pence an hour spread across its life. The decision that saves money is whether it has a thermostat at all, and whether the room lets that thermostat actually switch the heater off.
One room, or the whole house
Gas central heating comes out at £1.31 an hour in this table, above any single electric heater, and that needs a caveat. An hour of gas heats a whole house, not one room. An hour of a fan heater heats one room. Warm one room for an evening, and an electric heater at 54.7p an hour beats firing up a boiler built to heat every radiator in the house. Heat three or four rooms at once and gas is doing that work at a cost per room a plug in heater cannot match, because the boiler's fixed costs are then split across all of them.
The radiator and convector duty cycles here, 60% and 70%, are a typical single room once it is warm. A draughty room, a high ceiling or an open door pushes the real duty cycle towards the fan heater's 100%, erasing most of the saving a thermostat is supposed to offer.
Guess the cheapest
Which heats a home for the least money per kWh of heat?
Home sizes use Ofgem's typical domestic consumption values for gas from 1 July 2026 (low 6,000, medium 9,500, high 14,000 kWh a year), less the 10% a condensing boiler loses up the flue, as the heat the home needs. Ofgem.
The verdict
For an hour or an evening in one room, a thermostatted radiator or convector costs less than a heater with no thermostat, because the thermostat switches it off some of the time. A halogen heater on one bar is cheaper still, but only while you sit in front of it. None of that makes electric heating cheap next to gas; it is simply the cheaper way to warm one room for a few hours when heating the whole house would cost more.
Put your own numbers in
Prefilled with a fan heater running flat out. Change the hours a year to match how long you would actually leave it on.
Cost per meal
Set the purchase price to zero for the running cost alone.
Questions
How much does a 2kW heater cost per hour to run in the UK?
Between about 28.5p and 54.7p an hour among common electric 2kW heaters, at the current capped electricity rate, 26.32p per kWh. A fan heater with no thermostat runs flat out and costs about 52.6p an hour; a thermostatted oil filled radiator or convector costs less because it switches off some of the time.
Which is cheaper to run, a fan heater or an oil filled radiator?
The oil filled radiator, at about 31.6p an hour against about 52.6p for the fan heater, because its thermostat cuts the draw once the room is warm. A fan heater usually has no thermostat, so it keeps pulling its full 2kW the whole time it is switched on.
How much does it cost to run a 2kW heater all evening?
For four hours: about £2.11 for a fan heater run flat out, £1.47 for a thermostatted convector, and £1.05 for a halogen heater run on one bar.
How much does it cost to run a 2kW heater all winter?
At four hours a day across a roughly 120 day heating season, about £252.67 for a fan heater run flat out, down to about £126.34 for a halogen heater on one bar, with a thermostatted convector at about £176.87.
Is it cheaper to run one electric heater or the central heating?
For one room, an electric heater at 54.7p an hour or less usually beats £1.31 an hour of gas central heating, because that hour of gas is built to heat the whole house. Once you are heating several rooms at once, gas is doing more work for that same £1.31, and the comparison stops favouring the single heater.
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More heating and damp costs, or read how we work these out.
Prices used on this page
- Electricity, 26.32p per kWh. Ofgem price cap, direct debit, average of England, Scotland and Wales, including 5% VAT.. Ofgem energy price cap unit rates and standing charges. Checked 1 October 2026.
- Mains gas, 7.97p per kWh. Ofgem price cap, direct debit, average of England, Scotland and Wales, including 5% VAT.. Ofgem energy price cap unit rates and standing charges. Checked 1 October 2026.