A typical plug-in space heater uses 1,500 watts on high and about 750-900 watts on low. Because it is a resistive heater there is no meaningful startup surge.
- Running watts
- 1,500 WTypical; 750–1,500 W across models
- Starting watts
- NoneNo motor surge
- Per day
- 6 kWh8 h of use, cycling
- Current
- 12.5 AAt 120 V while running
Figures checked against DOE, ENERGY STAR and manufacturer data on . Your model's label is the final word.
Watts by model and setting
Most space heater models draw between 750 and 1,500 W while running; a typical one draws about 1,500 W. Assumes a 1,500 W heater on high for 8 hours with the thermostat cycling it on about half the time; running continuously it uses 1.5 kWh every hour.
- Heat setting: nearly all US plug-in heaters top out at 1,500 W (about 12.5 amps at 120 V), with a low setting around 750-900 W
- Thermostat cycling: once the room warms up, the element switches on and off, lowering average use
- Heater type (ceramic, oil-filled, infrared) changes how heat is delivered, not how much electricity 1,500 W of heat takes
- Fan-only or eco modes draw far less than heat modes
Running a space heater on a generator or power station
- Generator: at least 1,500 running watts. A generator rated 2,000 W or more covers it with room to spare.
- Power station: continuous output of at least 1,500 W. Pure sine wave output is the safe choice for motors and electronics.
| Power station capacity | Estimated runtime |
|---|---|
| 500 Wh | 0.6 h |
| 1,000 Wh | 1.1 h |
| 2,000 Wh | 2.3 h |
| 3,000 Wh | 3.4 h |
Based on 750 W average draw (running watts × duty cycle) and 85% usable capacity.
- A 1,500 W heater is one of the biggest plug-in loads: it will drain a 1 kWh portable power station in well under an hour on high
- On a generator, budget the full 1,500 W running; there is no surge, but it leaves little room on a 2,000 W inverter generator
- Plug it directly into the generator or a heavy-gauge cord rated for the load, and never leave it unattended
- Run generators outdoors only, far from windows and doors: carbon monoxide can kill
Add it to the generator calculator
Questions people ask
How many amps does a 1500 watt space heater draw?
About 12.5 amps at 120 volts, which is why it should have a 15- or 20-amp outlet largely to itself and should not share a power strip.
Can a portable power station run a space heater?
Only briefly. A 1,500 W heater empties a 1,000 Wh station in roughly 40 minutes on high; the low setting roughly doubles that.
Do energy-efficient space heaters use less power?
All resistive heaters turn electricity into heat at essentially the same rate, so 1,500 W of heat costs 1,500 W of electricity. Savings come from heating only the room you are in and using the thermostat.