How Much Does It Cost to Run a Space Heater All Night?
The formula
Cost per night = (watts ÷ 1000) × hours run × your electricity rate. Electric resistance heaters convert power to heat at essentially 100% efficiency, so wattage directly determines cost — there's no "efficient" plug-in heater that uses less energy for the same heat output.
Worked examples by heater size
| Heater power | 8 hours overnight | Per month (nightly) |
|---|---|---|
| 750 W (small) | $1.02 | $31 |
| 1,500 W (typical) | $2.04 | $61 |
| 2,000 W (large) | $2.72 | $82 |
Assumes $0.17/kWh, the approximate U.S. average residential rate. Use your own rate for an exact figure.
How to cut the cost
- Use a thermostat or timer instead of running continuously — most of the cost above assumes 8 straight hours, but a thermostat-controlled heater cycles off once the room is warm.
- Heat only the room you're in — close doors to avoid warming unused space.
- Compare against your central heating cost — for a whole house, a heat pump or gas system is usually cheaper; a space heater wins only for heating one small room.
Frequently asked questions
How much does it cost to run a space heater all night?
A typical 1,500W space heater run for 8 hours overnight at $0.17/kWh costs about $2.04. Run every night for a month, that is roughly $61.
Is it cheaper to leave a space heater on low all night or use a timer?
A thermostat or timer that only runs the heater as needed is almost always cheaper than leaving it on continuously, since it avoids heating an already-warm room.
Is a space heater cheaper than central heating overnight?
For heating one room, often yes. For heating a whole home, central heating or a heat pump is usually cheaper per unit of heat delivered.