How long will a power station run a space heater?
A 1,500 W space heater on high drains a 1,000 Wh power station in about 34 min (0.6 hours) — if the power station’s inverter can carry 1,500 W at all.
How to work it out
- 1,000 Wh = 1,000 Wh available
- 1,500 W ÷ 85% inverter = 1,764.7 W
- 1,000 Wh ÷ 1,764.7 W = 0.6 hours (34 min)
Heat is the hardest thing to make from a battery. Every watt of a resistance heater turns into heat, but making 1.5 kW for hours takes far more energy than a portable power station holds.
Adjust for your project
More options: Efficiency · Duty · Reserve
- In hours and minutes
- 34 min
- Energy delivered to the load
- 850 Wh
- Average draw from the battery
- 1,764.7 W
- Check the power station’s continuous AC rating too: many units in this size class cannot run a 1,500 W load at all, whatever their watt-hours.
Runtime by power station size
| Power station capacity | Runtime | Energy delivered to the load |
|---|---|---|
| 256 | 0.1 hours | 218 Wh |
| 500 | 0.3 hours | 425 Wh |
| 1000 | 0.6 hours | 850 Wh |
| 1500 | 0.9 hours | 1,275 Wh |
| 2000 | 1.1 hours | 1,700 Wh |
| 3600 | 2 hours | 3,060 Wh |
Why batteries and heaters don’t mix
- Check the continuous rating first. A 1,500 W heater needs an inverter rated above 1,500 W continuous; plenty of 1,000 Wh units are rated below that and will shut off.
- Low setting doubles the time, still short. At 750 W — the bottom of the extension service’s 750–1,500 W range — the same station lasts about 1.1 hours.
- Heat the person, not the room. An electric blanket at 60–100 W runs most of a night on the same battery — see how long a power station runs an electric blanket.
- Fuel stores far more heat. A 20 lb propane cylinder holds about 432,000 Btu — roughly 127 kWh of heat. That is why off-grid heating is usually propane, wood or diesel, with batteries only running the fan.
On the grid, the same heater costs about 26¢ an hour at 17¢ per kWh — see the cost to run a space heater. If you are heating with propane instead, read the manufacturer’s ventilation rules and keep a CO alarm nearby; how long a 20 lb propane tank lasts for heating does the fuel math.
Different size? Use the full Power Station Runtime Calculator.
What you’ll need
- Portable power station (about 1,000 Wh)Premium price
Battery, inverter and charger in one box. Check both the watt-hour capacity and the inverter’s continuous and surge watts against what you plan to run.
See options on Amazon (opens in a new tab) - Battery-operated carbon monoxide alarmBudget price
CPSC advises battery or battery-backup CO alarms whenever a generator is in use. Look for UL 2034 certification and test monthly.
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Frequently asked questions
How long will a power station run a space heater on low (750 W)?
About 1 h 8 min on a 1,000 Wh unit.
How long will a 3,600 Wh power station run a 1,500 W heater?
About 2 h 2 min (2 hours).
Other common sizes
- How long a power station runs a refrigerator — 12.9 hours on 1,000 Wh
- What size power bank for a Starlink Mini — About 1,000 Wh for a full day; 300 Wh lasts about 7 hours
- How long a power station runs an electric blanket — 4.3 hours on 500 Wh, 8.5 on 1,000 Wh
Sources
- Victron Energy — Energy Unlimited (book) (opens in a new tab) — Lead-acid charge efficiency 80–95% (85% suggested as a starting value); battery energy efficiency about 75% for full cycles, about 89% in partial state of charge; inverter efficiencies above 90%.
- Champion Power Equipment — Generator Wattage Chart (opens in a new tab) — Typical running and starting watts for household, RV and job-site appliances (a manufacturer’s planning chart — your nameplate wins).
- Virginia Cooperative Extension, BSE-301: Estimating Appliance and Home Electronic Energy Use (2020) (opens in a new tab) — Wattage × hours ÷ 1,000 = kWh per day; watts = amps × volts when only amps are listed; a refrigerator runs at full wattage about a third of the time; typical nameplate wattages.
- Starlink — Mini specification sheet (opens in a new tab) — Power consumption: average 25–40 W; input rating 12–48 V, 60 W.
- Starlink — Standard kit specification sheet (opens in a new tab) — Power consumption: average 75–100 W.