The short answer
A typical electric space heater needs about 1,500 W running, averaging about 1,500 W over time. A full day needs roughly 42,353 Wh of battery.
The load and who can run it
| Item | Typical value | Basis |
|---|---|---|
| Running watts | 1,500 W | typical planning value |
| Starting watts | No significant surge | typical planning value |
| Duty cycle | 100% | share of time drawing power |
| Average draw | 1,500 W | running watts × duty cycle |
A continuous resistive load — drains any battery quickly and stresses small generators.
Power stations that can run it (51)
Wattstanding calculationWattstanding calculation — runtime = capacity × 85% ÷ (running watts × duty cycle). Showing the 30 lowest-priced of 51 qualifying stations.
Generators that can run it (155)
Total your own list with the appliance load & runtime calculator.
Questions readers ask
How many watts does a electric space heater use?
A typical one runs on about 1,500 W; averaged over time it draws about 1,500 W. Check your own nameplate.
How many watt-hours do I need to run it for a day?
About 42,353 Wh of battery capacity for 24 hours, by our calculation (average draw × 24 h ÷ 85% efficiency).
Figures marked as Wattstanding calculations show their working; product figures come from the sources on each product page. How we work