How Many Watts Does a Space Heater Use?
Verified July 2026 Manufacturer + DOE typical ratings. Methodology
Space Heater wattage by type
| Setting | Draw | Runtime per 1,000Wh |
|---|---|---|
| Low setting | 750W | ~1.1 hr per 1kWh |
| Medium | 1,000W | ~51 min per 1kWh |
| High | 1,500W | ~34 min per 1kWh |
| Oil-filled radiator (avg cycling) | 900W effective | ~57 min per 1kWh |
This is the page where we talk you out of a purchase. Resistive electric heat is the single worst battery load in a home: continuous max draw, no duty cycle relief. Even the 6kWh EcoFlow Delta Pro Ultra runs a single heater on high for barely 3.5 hours. In a winter outage, the battery's job is protecting pipes-adjacent essentials (furnace blower so your gas furnace can run, fridge, phones) - not producing heat. A gas furnace's 500W blower delivers ~20x more heat per battery watt-hour than a space heater, because the gas does the heating.
How long real power stations run a space heater
Computed from each unit's rated capacity at 85% inverter efficiency and a 100% duty cycle (1500W running). Units that can't clear the start surge are excluded.
| Power station | Capacity | Estimated runtime | Price | |
|---|---|---|---|---|
| EcoFlow Delta Pro Ultra Longest | 6,144 Wh | 3.5 hours | $5,799 | Check price → |
| EcoFlow Delta Pro 3 | 4,096 Wh | 2.3 hours | $3,699 | Check price → |
| Anker SOLIX F3800 Plus | 3,840 Wh | 2.2 hours | $4,799 | Check price → |
| Bluetti Elite 200 v2 | 2,073 Wh | 1.2 hours | $1,699 | Check price → |
| Jackery Explorer 2000 v2 | 2,042 Wh | 1.2 hours | $1,499 | Check price → |
| Anker SOLIX C1000 | 1,056 Wh | 0.6 hours | $999 | Check price → |
| EcoFlow Delta 3 Plus | 1,024 Wh | 0.6 hours | $799 | Check price → |
| Bluetti AC70 | 768 Wh | 0.4 hours | $649 | Check price → |
⚡ Backing up more than a space heater?
Add your other appliances and outage length — our calculator sizes the whole load and shows exactly which units fit.
Size my full backup →Frequently asked questions
Can a power station run a space heater overnight?
Realistically no. Eight hours on low (750W) needs ~7,000Wh - only a maxed-out expansion system covers that, and it costs more than a whole-home standby generator.
What's the best way to stay warm during a power outage?
If you have gas/propane heat, back up the furnace blower (~500W) - that's the highest-value 500W in your house. Otherwise: one room, blankets, and an indoor-safe propane heater (Mr. Heater Buddy class) with CO alarm.
Do oil-filled radiators use less battery?
Slightly - they cycle a thermostat, averaging ~60% of rated draw. But 900W effective is still a battery-killer. They're better on generators than batteries.
Keep reading
- Full comparison database — every spec, side by side
- Best-for guides — ranked picks by use case
- 2026 state incentives — what still pays after the federal credit