Guide · 2026-11-11

How long can a power station run a fridge?

A fridge does not draw one steady wattage. The compressor starts, runs, and rests, so the number on the nameplate is not the all-day average. That is why RunTime’s load list has no fridge. The better starting point is the yellow EnergyGuide label, which gives the model’s estimated yearly electricity use in kilowatt-hours.

From kWh per year to average watts

Average watts = kWh per year × 1,000 ÷ 8,760. There are 8,760 hours in a 365-day year.

Arithmetic only, not a particular fridge: a label that reads 438 kWh per year works out to 438,000 ÷ 8,760, which is 50 W on average, or 1.2 kWh a day. Use the number on your own label.

The FTC describes that figure as an estimate based on typical use, and says the electricity an appliance uses depends on how you use it. Treat the label as a plan, not a promise, and measure if you can.

The hour math

Usable watt-hours are the station’s published capacity times inverter efficiency. A fridge plugs into an AC outlet, so RunTime uses the AC path and its 85% planning assumption. The station pages in this library do not print an inverter efficiency.

At a 50 W average, a 1,024 Wh station has 870.4 Wh to give, which is about 17 hours 24 minutes. A 256 Wh station has 217.6 Wh, which is about 4 hours 21 minutes. Open RunTime, pick your station or type its watt-hours, choose “Type watts” for the load, and enter the average from your label.

The startup check is separate

Runtime is about energy. Starting the compressor is about power. A station has to hold the running watts inside its continuous AC rating and the start inside its surge rating, which is a short permission, not a second tank. The station pages list both figures from each maker’s page. The fridge’s own nameplate or manual is the place to look for its running and starting figures. If you cannot find a starting figure, a plug-in meter during a compressor start, or the fridge maker’s support line, is a better source than a guess.

How to read a power station label explains continuous and surge. How to find a device’s watts from its label explains why a nameplate’s volts times amps is a ceiling, not an average.

Measure if you can

A plug-in meter left on the fridge for a full day gives kilowatt-hours for that day in your kitchen. Divide by 24 for average watts, and type that into RunTime instead of the label figure. None of this is a recommendation of a station or a fridge.

Sources: FTC, Appliance Shopping With the EnergyGuide Label and 16 CFR 305.14, label content for refrigerators and freezers, read 2026-11-11. Station capacities and AC ratings are from the maker pages cited on each station page.