What Size Power Station Do I Need for a Space Heater?
Understand why electric space heaters are difficult battery loads and calculate the inverter and energy required for short heating periods.
Space heaters are usually high continuous-power loads, so both inverter output and stored watt-hours become constraints almost immediately.
Space heaters are among the worst portable-battery loads because they convert electricity directly into heat at roughly 1,500W. A station can power one only if the inverter supports the draw, but runtime is short unless the battery is very large.
What matters
- Use the heater’s electrical input, commonly near 1,500W at full power.
- Heating for hours can consume several kWh quickly.
- Low settings may cycle or reduce power depending on the heater design.
- Battery backup is often more efficient when focused on the heating system controls or blower rather than resistance heat.
Decision factors that change the answer
Continuous wattage
Most full-size portable heaters draw around 1,500W on high.
Battery drain
At 1,500W, a 2kWh station can be depleted in roughly an hour after losses.
Low setting
A 750W mode roughly doubles runtime versus 1,500W but still uses large amounts of energy.
Alternative heat
Where safe and appropriate, non-electric heat often preserves battery energy for more critical loads.
Relevant examples from our tracked database
| Model | Capacity | AC output | Solar input | Weight |
|---|---|---|---|---|
| BLUETTI AC200L | 2,048 Wh | 2,400 W | 1,200 W | 62.4 lb |
| EcoFlow DELTA 2 Max | 2,048 Wh | 2,400 W | 1,000 W | 50 lb |
| Jackery Explorer 2000 Plus | 2,042.8 Wh | 3,000 W | 1,400 W | 61.5 lb |
This table is a model-level reference from our current source-linked database, not a claim that every model from either brand has the same characteristics.
How to size it
- Read the heater input watts.
- Multiply by intended hours of use.
- Add inverter losses and reserve.
- Verify continuous output exceeds the heater draw.
A 1,500W heater running for one hour consumes about 1.5kWh before conversion losses, so even a 2kWh-class station can be depleted quickly.
Worked example
A 2,048Wh station with 85% usable AC energy provides about 1.74kWh. At a 1,500W heater load, idealized runtime is only about 1.16 hours before reserve.
Common buying mistakes
- Sizing only by inverter watts.
- Expecting a 1kWh station to provide many hours of 1,500W heat.
- Ignoring other essential outage loads.
Space heaters are technically simple but energy-intensive. Use battery heat selectively unless you have a very large storage system.
Check the underlying numbers
Use these site resources to replace generic assumptions with your own load or the source-linked data behind this guide.
Use the numbers before choosing a model
Start with your load list. The battery needs enough watt-hours for the desired runtime and enough continuous/surge watts to operate the appliances at the same time. Then check whether your recharge method can replace the energy you expect to consume.
For outage planning, we recommend keeping reserve capacity instead of designing a system that reaches 0% at the end of the forecasted outage.
Next step
Estimate battery runtime → or Build a critical-load energy budget →.