How much does an electric heater cost to run per hour?
Short answer
An electric heater uses exactly its rated power: a 2000 W unit uses 2 kWh for every hour it runs at full output. To find the cost, multiply the kW by the hours of use and by the price per kWh printed on your electricity bill.
The electric heater is the appliance people most dread on the bill, and the reason is that its consumption is direct and unforgiving: unlike a fridge or an air conditioner, there’s no cycling and no compressor. What the label says is what it draws, for as long as it’s on.
The maths, in two steps
Step 1: convert watts to kilowatts. Divide by 1000.
Step 2: multiply by hours of use. That gives you kWh consumed.
| Power | Per hour | 4 hours a day, 30 days |
|---|---|---|
| 800 W (low-output panel) | 0.8 kWh | 96 kWh |
| 1200 W (quartz / halogen) | 1.2 kWh | 144 kWh |
| 2000 W (fan heater) | 2.0 kWh | 240 kWh |
| 2400 W (large fan heater) | 2.4 kWh | 288 kWh |
To turn that into money, take your electricity bill and find the price per kWh. That figure varies by distributor, tariff category and month, so there’s no point us printing one here: the one on your bill is the only correct one.
Monthly consumption (kWh) × your bill’s price per kWh = what that heater costs you.
What changes the bill most isn’t the heater — it’s the thermostat
A heater without a thermostat runs at 100% permanently. One with a thermostat reaches the temperature you set, cuts out, and switches back on when the room cools. In a well-closed room that can mean it works effectively half the time.
That’s the difference between 2000 W for 4 real hours (8 kWh) and 2000 W for 2 effective hours spread across 4 (4 kWh). Half the bill, same comfort.
So if you’re buying an electric heater for regular use, the thermostat is the feature that saves you the most money — far more than the heating element technology.
How to use less with the one you already own
- Close the door. Heating one room is cheap; heating a whole house with a portable heater is impossible and ruinous.
- Use the low setting. Most have two or three levels. 1200 W for twice as long costs the same as 2400 W, but the low setting is often enough to maintain temperature, so you don’t actually need twice as long.
- Block draughts. A gap under the door or a leaky window keeps the heater running far longer than necessary.
- Don’t use electric for continuous heating if you have gas. Electric works best as fast, targeted heat.
And the instantaneous load on your wiring
A practical point that’s often missed: a 2000 W heater at 220 V draws roughly 9 amps. If you plug it into the same circuit as other high-draw appliances (a microwave, an iron, an electric water heater), the breaker will likely trip. That’s not a fault in the heater — it’s how much you’re asking of that circuit.
Frequently asked
Which electric heater uses the least power?
They all use the same per watt: there is no genuinely 'low consumption' electric heater, because practically 100% of the electricity becomes heat. What changes is the power rating you choose and how long you need it on. A 2000 W fan heater warms a small room fast and then you switch it off; a 400 W low-output panel warms slowly but may stay on longer. The real difference comes from the thermostat: a heater that cuts out on its own once it reaches temperature can use half as much as one running flat out all the time.
Is an electric or a gas heater cheaper?
Heating with natural gas is considerably cheaper per unit of heat than heating with electricity, so if you have a gas supply, that's the economical route for heating a room continuously. Electric heaters win elsewhere: no installation required, no carbon monoxide risk, you can move them from room to room, and they're ideal for quickly warming one specific space or somewhere the gas doesn't reach. Plenty of homes use both: gas for the house, electric for the bathroom in the morning or the home office.
Is it true that quartz heaters use less?
Not in themselves. A 1200 W quartz heater draws 1200 W, exactly like any other appliance at that rating. What makes quartz (and halogen) different is that they heat by radiation: they warm you directly, almost instantly, rather than heating all the air in the room. That sometimes means you can run them for less time or on a lower setting, and then they do use less. But at the same power for the same hours, consumption is identical.
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