Electric-heater cost calculator
Work out how much it costs to run an electric heater, from its power rating, how long you run it and your electricity price.
Result
Cost per year
Cost per week
How to use this calculator
- Check your heater's power rating — most portable electric heaters are 1–3kW.
- Enter how many hours a day and days a week you run it.
- Enter your electricity price per kWh.
- Read the estimated cost per week and per year.
Assumptions
- Assumes the heater runs at full rated power the whole time it's on — a thermostatic heater cycling on and off will cost somewhat less than this in practice.
Technical details: what the fields mean
- Heater power
powerWatts - Heater power rating — 1000W, 2000W and 3000W are common settings on portable electric heaters.
- Hours per day
hoursPerUse - How many hours a day the heater actually runs.
- Days per week
daysPerWeek - How many days a week you use it.
- Electricity price
pricePerKwh - Your electricity price per kWh — check a recent bill.
Methodology
Energy per week = power (kW) × hours per day × days per week. Cost = energy × price per kWh, projected to a year.
Worked example
2000W heater, 4 hours/day, 7 days/week, 27p/kWh
Inputs: powerWatts=2000, hoursPerUse=4, daysPerWeek=7, pricePerKwh=0.27
Result: £15.12/week, £786.24/year
Practical guidance
- Electric resistive heaters are expensive to run continuously — for whole-room or whole-home heating, other systems (heat pumps, gas central heating) are usually cheaper per kWh of heat delivered.
- A thermostat or timer reduces actual running time well below 'hours switched on'.
Common mistakes
- Assuming a heater's maximum wattage setting is what it always draws — many heaters have adjustable power settings.
- Using electric heaters as a primary whole-home heat source without comparing the running cost to your main heating system.
FAQs
How much does it cost to run a 2kW electric heater?
At 4 hours a day, 7 days a week and 27p/kWh, about £15.12 a week — enter your own figures above for an exact cost.
Are electric heaters expensive to run?
Per unit of heat, yes — electric resistive heating is generally more expensive than gas central heating or a heat pump, though cheaper to install.