How Much Electric Do
Electric Heaters Use?
Electric heaters are simple to budget for once you know two numbers: the heater's wattage rating plus the current Ofgem unit rate. At the April 2026 cap of 24.7p per kWh, a typical 2kW plug-in heater costs around 49p per hour to run. This guide breaks it down by heater size plus shows where you can save.
An electric heater uses roughly 1 to 3 kWh of electricity per hour depending on its wattage rating. At the current Q2 2026 Ofgem unit rate of 24.7p per kWh, that means 25p per hour for a 1kW heater, 49p per hour for a 2kW heater plus 74p per hour for a 3kW heater. Running a 2kW heater for 6 hours a day across an average UK winter month costs around £88 in electricity. Lower-wattage heaters with thermostats plus timers cut this significantly.
The figures that matter
1kW heater
Smallest typical plug-in heater. Suits a small bedroom or office.
2kW heater
The UK average for a fan plus convector heater. Heats a small living room.
3kW heater
High-output oil-filled or fan heater for larger rooms.
Current unit rate
Ofgem Q2 2026 cap, average direct debit price. Updated quarterly.
Four things to consider
wattage matters most
Double the wattage means double the running cost. Match the heater to the room size, not the maximum heat you can buy.
thermostats save 30%+
A thermostatic heater cycles on plus off automatically. Real-world running costs drop sharply versus uncontrolled heaters.
avoid 24/7 use
Continuous heating with a portable electric heater is rarely cheaper than running central heating in the relevant zone.
match heater to space
1kW for a 10m² bedroom, 2kW for a 15 to 20m² living room, 3kW only for larger spaces or short bursts.
How to calculate the running cost of any electric heater
Working out the running cost of any electric heater is straightforward. You need two pieces of information: the wattage rating printed on the heater plus your current electricity unit rate.
The formula:
- Step 1: Convert watts to kilowatts. A 2000W heater is 2kW.
- Step 2: Multiply by hours used. 2kW for 1 hour equals 2 kWh.
- Step 3: Multiply by your unit rate. At the current 24.7p Ofgem cap that is 2 × 0.247 = 49.4p per hour.
Real numbers at 24.7p per kWh (Q2 2026 Ofgem cap):
- 1kW heater: 24.7p per hour, £1.48 per 6 hours, £44 per month at 6 hours daily.
- 1.5kW heater: 37p per hour, £2.22 per 6 hours, £67 per month at 6 hours daily.
- 2kW heater: 49p per hour, £2.96 per 6 hours, £89 per month at 6 hours daily.
- 2.5kW heater: 62p per hour, £3.71 per 6 hours, £111 per month at 6 hours daily.
- 3kW heater: 74p per hour, £4.45 per 6 hours, £133 per month at 6 hours daily.
Where the savings come from. A heater with a built-in thermostat does not run continuously. It heats the room to the set point then cycles. In a well-insulated UK living room a thermostatic 2kW heater typically runs at full power for around 30 to 40 percent of the time, which roughly halves the monthly cost versus the figures above. Heaters without thermostats run at full draw the whole time you have them switched on.
Heater types compared on running cost. Fan heaters are cheap to buy plus heat fast yet have poor efficiency over long use. Oil-filled radiators take longer to warm but retain heat plus cycle less often. Halogen heaters give targeted spot heating which suits short bursts. Convector heaters fall between fan plus oil-filled on cycle behaviour. The wattage on the label is what dictates the cost. The technology mostly affects how that cost is distributed through the day.
Real number ranges
Hourly running cost by heater wattage (24.7p per kWh)
A typical 2kW heater day
1 hour pre-work
Heater on for 1 hour to warm the kitchen plus living room. Cost: 49p.
off at work
Heater off while household out. Zero cost. Smart plug or timer makes this automatic.
4 to 5 hours peak use
Heater on through evening with thermostat cycling. Cost: roughly £1.50 to £2.50.
bedroom 30 mins
Brief warm-up before bed. Cost: 25p. Daily total roughly £2 to £3.
Four ways to cut electric heater running costs
Use a thermostatic model
A built-in thermostat cycles the heater off when room temperature is reached. Saves 30 to 50 percent versus uncontrolled heaters.
Heat the person, not the room
Spot heating with a small panel or halogen heater costs less than warming a whole large room.
Combine with a smart plug
Smart plugs plus timers prevent heaters being left running overnight or while you are out.
Insulate before you upgrade
An extra 100mm of loft insulation cuts heating demand more than any heater swap.
Compare the options
Electric heater (plug-in)
- •Cheap to buy at £30 to £120 for most domestic models.
- •No installation cost. Plug-in plus go.
- •Runs at 24.7p per kWh on the current Ofgem cap.
- •Heats one room only. Suits short bursts plus single-room use.
- •2kW for 6 hrs daily costs roughly £89 per month.
Gas central heating (zone)
- •Higher upfront cost for the boiler plus the system itself.
- •Runs at 5.7p per kWh on gas under the current Ofgem cap.
- •Heats whole zones. Better for sustained use through the day.
- •Modern boiler is around 90% efficient. Net cost still lower than electric per kWh delivered.
- •Equivalent zone costs roughly £30 to £50 per month for the same warmth.
Heating costs are one part of the picture. Our full Appliances hub covers running costs across every major household appliance from kettles to heat pumps so you can build a complete view of your electricity bill.
Visit the Appliances Hub
This article is one chapter inside our complete Appliances knowledge base. The hub covers running costs across every major household appliance from kettles to heat pumps.
More on appliance running costs
Three closely related running cost articles. how much electric does a heater use covers the wider category. how much electricity does a heat pump use compares against the lower-cost alternative. how much electric does an electric blanket use shows the cheapest spot-heating option.