An electric heater consumes as many kilowatt-hours per hour as its power rating in kilowatts: a 2000-watt heater therefore consumes 2 kWh per hour and a 1500-watt heater 1.5 kWh. What the electricity consumption of an electric heater costs per hour depends on your kWh rate. With an example rate of 30 cents per kWh, you pay approximately 60 cents per hour on the highest setting.
How do you calculate the power consumption of an electric heater?
The calculation is simple: power in kilowatts multiplied by the number of hours multiplied by your rate per kWh. A 2000-watt heater is 2 kW. If it runs for an hour at full power, you use 2 kWh. The rate varies per energy contract, so check your annual statement or your supplier's app. In the examples below, we calculate using 30 cents per kWh; this is an assumption, not a current rate.
A heater does not run continuously at full power
The stated wattage is the maximum. As soon as the room reaches the set temperature, a heater with a thermostat throttles back or turns off temporarily. In practice, your actual consumption is therefore often lower than the number on the packaging, especially in a well-insulated room. In a drafty room with cold walls, the heater will stay on longer.
What does it cost to heat a room per day?
Take a heater that runs at full power for an average of three hours a day. That is 6 kWh, or approximately 1.80 euros per day at our example rate. If you heat a home office for eight hours, but the heater runs for half that time, you end up at 8 kWh and approximately 2.40 euros. The table below provides an overview.
| Power | Consumption per hour | Cost per hour (30 ct/kWh) | Cost for 4 hours |
|---|---|---|---|
| 1000 watts | 1 kWh | € 0.30 | € 1.20 |
| 1500 watts | 1.5 kWh | € 0.45 | € 1.80 |
| 2000 watts | 2 kWh | € 0.60 | € 2.40 |
Saving smartly with an electric heater
Only heat the room you are sitting in and close the door. A heater is particularly cost-effective as supplemental heating for one room, while the rest of the house is at a lower temperature. You can read more about that trade-off in our article Is an electric heater cheaper than central heating for one room?. In addition, use a timer so that the heater does not run unnecessarily, and place it in a safe location, as described in where to place an electric heater most safely.
Direct answer: an electric heater consumes as many kWh per hour as its power in kW. 2000 watts is 2 kWh per hour, 1500 watts is 1.5 kWh. Multiply by your kWh rate for the costs.
Highlighted: the AirFlow HW2002 electric heater
The Dynter HW2002 is a compact electric heater with adjustable power, suitable for heating a single room.
Power: 1500 - 2000 watts
Suitable for: rooms up to 40 m²
Temperature: 15°C to 45°C adjustable
Controls: LCD touchscreen and remote control
Extras: timer function, oscillating function, overheating protection, and tip-over protection
Dimensions and weight: 18 × 18 × 45 cm, 1.6 kg
Thanks to the timer and the adjustable power, you keep control over your consumption. Also read which electric heater suits your room before you choose.
Is it okay to leave a heater on all night?
That is a safety question that you should look at separately from the costs. We discuss it in Is it okay to leave an electric heater on all night?. Always follow your device's manual.
Would you like to get started yourself? View the Dynter HW2002 electric heater or discover all Dynter heaters.
Frequently asked questions
How much does a 2000-watt heater consume per day?
At full power and on for 24 hours that would be 48 kWh, but that is rarely realistic. With a thermostat and a few hours of use per day, the consumption is much lower. Calculate based on the hours the heater is actually heating.
Is a lower setting more economical?
Yes, you consume less per hour. However, a higher setting might be needed for a shorter time to get the room to temperature. The total consumption therefore depends on how long the heater has to work.
Does a heater consume power on standby?
A little bit, for example for the display or the remote control. Unplug it if you are not using it for a long time.
How do I measure the actual consumption?
With an energy meter between the wall outlet and the heater, you can see exactly how many kWh the device consumes. That is much more accurate than an estimate.
Is an electric heater always cheaper than central heating?
Not always. Per kWh, gas or heat pump heat is often cheaper, but a heater pays off if you are only briefly heating one room. See our comparative article above.