Quick answer: A typical 1500W electric heater costs about £0.37 per hour to run in the UK (at 24.5p/kWh) or $0.26 per hour in the US (at 17c/kWh). Running it 4 hours a day costs roughly £44/month in the UK or $31/month in the US. Use the calculator below with your own wattage and electricity rate for an exact figure.
Electric Heater Running Cost Calculator
Auto-filled with a typical average – edit to match your own tariff
How Much Does It Cost to Run an Electric Heater?
The running cost of any electric heater depends on three things: its wattage, how many hours you run it, and your electricity rate. The formula is simple:
Cost = (Wattage / 1000) × Hours Used × Electricity Rate per kWh
A heater doesn’t always run at full power the whole time – thermostats cycle the element on and off once a room reaches temperature. Most heaters run at full draw 30% to 70% of the time depending on room size, insulation and outside temperature, so treat these figures as a “heater running flat out” ceiling rather than an exact bill prediction.
Electric Heater Cost by Wattage (UK & US)
| Wattage | Cost/Hour (UK, 24.5p) | Cost/Hour (US, 17c) | Cost for 8 Hrs/Day, 30 Days (UK) |
|---|---|---|---|
| 500W | £0.12 | $0.09 | £29.40 |
| 750W | £0.18 | $0.13 | £44.10 |
| 1000W | £0.25 | $0.17 | £58.80 |
| 1500W | £0.37 | $0.26 | £88.20 |
| 2000W | £0.49 | $0.34 | £117.60 |
| 2500W | £0.61 | $0.43 | £147.00 |
Which Type of Electric Heater Is Cheapest to Run?
All resistive electric heaters convert nearly 100% of electricity into heat, so a 1500W fan heater and a 1500W oil-filled radiator cost the same per hour of full-power use. The real difference is how efficiently each type holds and spreads heat, which changes how many hours you actually need to run it:
| Heater Type | Typical Wattage | Best For |
|---|---|---|
| Fan Heater | 1000-2000W | Fast spot heat, small rooms |
| Oil-Filled Radiator | 1500-2500W | Slow, steady background heat |
| Ceramic Heater | 750-1500W | Quick warm-up, safe surface |
| Infrared/Radiant Panel | 400-1200W | Heating people directly, not air |
| Convector Heater | 1000-2000W | Whole small room, silent |
5 Ways to Cut Your Electric Heater Bill
- Heat the room, not the house – use a smaller heater in the one room you’re in instead of central heating for an empty house.
- Use a thermostat/timer model – cycling on/off at a set temperature uses far less energy than a heater left on constantly.
- Close doors and draught-proof – even a well-sized heater wastes power heating a draughty room.
- Choose radiant heaters for spot-heating – infrared panels warm you directly at lower wattage instead of heating the whole air volume.
- Check your off-peak tariff – some UK/EU suppliers offer cheaper overnight rates; storage heaters can exploit this.
FAQs
Is it cheaper to leave an electric heater on low all day or heat in bursts?
For most rooms, heating in bursts when you’re actually in the room is cheaper overall, since a heater left on all day – even on low – still consumes power continuously. The exception is very well-insulated rooms with thermostatic heaters, where a low constant setting can avoid the higher draw of repeatedly reheating a cold room from scratch.
How many watts does a room need to heat comfortably?
A rough rule of thumb is 10 watts per square foot for a room with average insulation and an 8ft ceiling (so a 150 sq ft bedroom needs roughly 1500W). Poorly insulated older rooms or high ceilings may need 15-20 watts per square foot.
Does a bigger heater always cost more to run?
Only while it’s on. A bigger heater draws more watts per hour, but it also warms the room faster and may cycle off sooner via its thermostat, so total daily cost can end up similar to a smaller heater running for longer.
How do I find my electricity rate per kWh?
Check a recent electricity bill – it will list your rate in pence/kWh (UK), cents/kWh (US), or your local currency per kWh. If you’re on a variable or time-of-use tariff, use your average or peak rate for a conservative estimate.
Is a heat pump cheaper to run than an electric resistance heater?
Yes, significantly – a heat pump moves existing heat rather than generating it from electricity, so it can produce 2-4x more heat per unit of electricity than a plug-in electric heater. This calculator is for standard resistive heaters (fan, oil-filled, ceramic, infrared, convector), not heat pumps.
Does room size affect my heater running cost?
Yes indirectly – a bigger or draughtier room needs a higher-wattage heater or more hours to reach the same comfort level, which increases cost even though the per-watt price of electricity stays the same.