Small space heater Runtime Estimate

Resistive heaters drain batteries quickly. Power setting and thermostat mode can change draw, so plan from the exact mode you will use.

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Planning wattage range

750-1500 W. Use a measured average when the device matters.

Planning default

750 W at 100% duty cycle, or about 750 W average load.

Confidence label

Estimated. Treat the result as a planning estimate, not a lab measurement.

1,024 Wh example

With 85% efficiency and a 10% reserve, about 783 Wh remains usable. At the default load, that is roughly 1h 3m. Runtime math does not prove the station can supply the required AC output or startup surge.

Evidence behind these load values

Published device values and editorial calculator assumptions have different evidence. An editorial range is a starting input, not a measured category range; replace it with your device reading. Context links explain units or compatibility and do not prove the numbers. The check date records the evidence classification, not a new hardware test.

Evidence type: Source-reported range · Editorial planning default
Source type: Editorial · Official
Confidence: Estimated
Conditions: Heat setting and thermostat or Auto-Eco cycling can change average draw. The official model example supports 750-1,500 W settings, not a universal category range.

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Evidence behind these load values
Value	Evidence type	Conditions	Source and dates	Confidence
Planning wattage range750-1,500 W	Source-reported range	Operating state: Mixed or variable Output path: AC Measurement interval: Unknown	Lasko Ellipse space heater product pageSource date: UnknownChecked: Aug 8, 2026	estimated
Planning default750 W	Editorial planning default	Operating state: Steady Output path: AC Measurement interval: Unknown	No separately attributed sourceSource date: UnknownChecked: Aug 8, 2026	estimated
Duty cycle100%	Editorial planning default	Operating state: Steady Output path: AC Measurement interval: Unknown	No separately attributed sourceSource date: UnknownChecked: Aug 8, 2026	estimated

Device measurement guide

Use the measured average

Enter a steady watt reading or a full-cycle average in the runtime calculator. Use 100% duty cycle for an average that already includes on and off periods.

Device wattage (W): Read watts after a steady load settles; record energy over time for a cycling load.
Duty cycle (%): Average watts calculated from Wh divided by hours already include off-cycle time, so do not apply duty cycle again.

How to Measure Device Watts for Runtime Planning

Use this load in the runtime calculator

Verify your watts

Check the device label for running watts or input amps and volts.
Use a plug-in watt meter for AC loads when the result matters.
For cycling loads, measure long enough to capture on/off behavior.

Open wattage library

Check output path

AC inverter loads usually lose more energy than direct DC loads.
Keep reserve for cold weather, battery age, and load changes.
Do not treat label capacity as fully usable watt-hours.

Read the method

Check surge and output

Runtime does not prove a station can start a compressor or motor.
Compare device startup watts with the station surge rating.
Compare running watts with the station continuous output rating.

Check startup surge

How to use this scenario

Start with 750 W if you do not have a watt-meter reading yet.
Small space heater is treated as a continuous load, so runtime is sensitive to the real wattage you enter.
Keep at least a planning reserve because battery age, temperature, output path, and device settings can move the result.

Watch-outs

The scenario wattage is an estimate. Measure the real load before relying on it for outage, travel, or critical planning.
Runtime does not prove the station can start or safely run the load. Check continuous output and startup surge before trusting a station.

Sources

EnergySage space heater wattage guide (editorial) - Lists 1,500 W as a common space-heater draw.
Reliant appliance energy comparison (editorial) - Compares common home device wattage such as LED TV, desktop computer, fan, microwave, and space heater.
Lasko Ellipse space heater product page (official) - Official specifications list 750-1,500 W for this model and describe thermostat/Auto-Eco operation. A single model does not establish a universal category range.

Use this load in the runtime calculator Check source wattage ranges Find a practical power station size Compare runtime by battery capacity Check startup surge

Related Scenarios

Compare nearby loads before assuming one wattage profile covers your setup.