How long will a freezer stay cold without power?
Scenarios Updated 2026-08-08
Two different questions get asked as one. How long the food stays frozen with no power at all is a thermal question about the cabinet and what is in it, and this library holds no measurement of it. How long a battery keeps the compressor cycling is an electrical question, and that one has an exact answer.
The electrical answer is smaller than almost everyone expects. A chest freezer draws about 30 W while its compressor runs, which is less than a games console at idle, and every published US machine in this library carries it without strain. What decides the hours is the battery, not the inverter.
A freezer is almost free to run
What refrigeration actually costs
The compressor-running figures and the certified annual energy behind them. Both loads are derived the same way and carry the same warning: the running watts are what the compressor pulls WHILE RUNNING, and it is switched off much of the time.
Derived from a certified annual figure rather than read off a plate. The cabinet behind this figure is a Midea chest freezer, and we have found no published amps or watts for it: its own spec page and EnergyGuide label carry the certified year and no electrical rating. That is one search of one maker’s documents, not a statement about the category.
See the record →The FTC EnergyGuide label on a 7 cu ft manual-defrost cabinet. This is the anchor every other freezer number here is checked against.
The number to size a battery against. It already contains the duty cycle, which is why it is so much smaller than running watts times twenty-four.
The certified annual kilowatt-hours on the label, divided by 365 days. The annual number is the maker’s; the division is ours.
For contrast, and it is the larger of the two: a fridge opens more often, holds a smaller temperature difference and carries a defrost cycle.
See the record →A compressor’s locked-rotor demand, as a multiple of its running draw. Large in ratio and trivial in absolute terms, because the running draw is so small.
Official spec + Derived from official coefficients + Derived by WattPairverified 2026-08-01appliance records · refrigeration
That start-up multiple is the reason the verdict is not automatic on paper and is uniform in practice. Multiplied out it comes to a demand every machine here clears without touching its surge ceiling, and the load ratio never rises above a few percent of continuous output. The honest reading is that "what size power station do I need for a freezer" is the wrong question. Almost any of them starts it; the choice is about how long.
What a battery actually buys
Live runs, largest and smallest
The same load against two ends of the library. The verdict is identical and the hours are not — which is the whole point of the page. Hours are printed only for the 7 of 12 machines whose records carry a usable-capacity figure to divide.
The longest run in the library on this load, and the load ratio is barely off the floor. Nothing about the inverter is being tested here; this is a battery-size answer.
Show the working →The smallest machine here starts it just as comfortably. What changes is the hours — and how much of the draw is the machine keeping itself awake.
Show the working →The fridge for comparison, on the same battery. Roughly twice the load and roughly two-thirds of the hours.
Show the working →The gap between those two runs is not the gap between the batteries, and this is the finding worth taking away. On the large machine the freezer accounts for 26 W of a 36 W total, with the rest being the station’s own self-consumption. On the small one the load is the same 26 W against a 38 W total — the machine is spending 12 W on staying switched on. Roughly a third of a small station’s discharge, on a load this light, is the station itself.
The half we cannot answer
How long the contents stay frozen with the power off, and what is still safe afterwards, are not electrical questions and this site publishes no figure for either. They depend on how full the cabinet is, how well it is insulated, the room temperature and how often the lid is opened — none of which is in any record here. The federal food-safety guidance covers exactly that, it is maintained by people who do test it, and it is where the second half of this question belongs. Wording checked against the USDA and FoodSafety.gov outage pages on 2026-08-08.
Sizing it for your own outage
Four steps, in the order that changes the answer most.
Find the kilowatt-hours per year on your own EnergyGuide sticker and divide by 365. That is your daily figure, and it already includes the duty cycle.
Self-consumption is a real share of the total on a light load. The calculator counts it; a watts-times-hours estimate on the back of an envelope does not.
Open the source →Refrigeration is the load that runs for the whole outage rather than in bursts, so the useful unit is days of autonomy.
The single largest variable in the thermal half is one you control for free, and it costs nothing to get right.