Can a power station run a freezer in a power cut?

By the Ferncharge team · Figures last checked 21 October 2026

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The short answer: often, yes, but you may not need to. The Food Standards Agency says food in a full freezer should stay frozen for up to 48 hours (24 hours if it's half full) if you keep the door closed, and notes these are estimates (FSA). If a cut runs longer, or you want a margin, a freezer's daily energy is modest: Which? estimates a chest freezer uses about 178 kWh a year, which is roughly 490 Wh a day (Which?). The harder part is the compressor's start-up surge.

Compared on manufacturers' published specs. Ferncharge has not tested these products. Estimates only.

Add a fridge-freezer to the sizing calculator (pre-filled with cautious figures), then change the watts and hours to match your freezer.

First: keep the door shut

Before you plug anything in, the FSA's advice is to keep the freezer closed. A full freezer holds its temperature longer than a half-empty one (FSA). For a short cut, a closed freezer may need nothing at all. A power station helps most when a cut is likely to run past those times, or when the freezer is part full.

Step 1: energy (watt-hours). How much does it use a day?

The best figure is your own freezer's energy label, which gives its consumption in kWh per year. To turn that into an average draw:

average watts = kWh per year × 1,000 ÷ 8,760 (hours in a year)

Using Which?'s average estimates by type (Which?):

Freezer type	Which? estimate	Average draw	Per day
Chest freezer	178 kWh a year	about 20 W	about 488 Wh
Tall freezer	212 kWh a year	about 24 W	about 581 Wh
Under-counter freezer	132 kWh a year	about 15 W	about 362 Wh

Our arithmetic from the Which? estimates, which are averages. Your own freezer's label is a better starting point, and real use will differ.

From a power station's mains socket, allow for our assumed 10% inverter loss and roughly 90% usable capacity on a LiFePO4 battery (methodology): about 810 Wh is available from every 1,000 Wh of rated capacity.

Example: a chest freezer at about 488 Wh a day for a 12-hour cut uses about 244 Wh. That needs about 300 Wh of rated capacity on our assumptions, before anything else you run.

Step 2: start-up. Can the power station start the compressor?

A freezer doesn't draw its average all the time: the compressor switches on and off, and each start briefly draws much more. BLUETTI's manual says devices with motors or compressors may start at 2–4 times their rated power (BLUETTI manual), and EcoFlow says a fridge's start-up surge is typically 2–3 times its running watts (EcoFlow).

So check two figures on the power station's spec sheet:

Continuous AC output: at least the freezer's rated input in watts (on its rating plate, not the average above).
Surge or peak output: enough for the start-up. The cautious end of BLUETTI's range is 4 × the rated input.

If something else is running when the compressor starts (a kettle, a microwave), add those watts too.

Fridge-freezers and fridges

A fridge-freezer works the same way: use its energy label for daily energy and its rated input for the start-up check. The FSA says a fridge should stay cold for up to 4 hours if you keep the door closed as much as possible (FSA), so the fridge side runs out of time sooner than the freezer. See our power cuts guide for the 12-hour winter example with a fridge-freezer.

Safety

Keep the power station dry, on a hard surface and away from the freezer's door seals, follow both manuals, and never connect a power station to your home's wiring. See our safety guide.

FAQs

How long will food stay frozen in a power cut?

The FSA says up to 48 hours in a full freezer and 24 hours if it's half full, if you keep the door closed. It notes these are estimates.

How much electricity does a freezer use in a day?

Divide the kWh per year on its energy label by 365. Which? estimates a chest freezer uses about 178 kWh a year (about 488 Wh a day) and a tall freezer about 212 kWh (about 581 Wh a day).

What size power station do I need for a freezer?

For energy, multiply the freezer's daily Wh by the days you need, then divide by about 0.81 for the mains socket on our assumptions. For output, check the continuous rating covers the freezer's rated input and the surge rating covers about 2–4 times that.

Why does my power station switch off when the freezer starts?

The compressor's start-up draw can exceed the power station's surge or continuous rating, especially with other appliances running. Run the freezer on its own and check the surge figure in the manual.

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