How long does a freezer last without power? Fridge and freezer

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When the power goes, the fridge and freezer are the first thing many people think of. The good news is that a short power cut of a couple of hours usually does the food no harm.^[1] The most important thing you can do yourself is keep the doors closed.

In short: Don't open the fridge or freezer unnecessarily.^[1] A full freezer holds its temperature for about 48 hours and a half-full one for about 24 hours if the door stays closed, and an unopened fridge keeps food cold for about 4 hours.^[2]

Before the power goes

The Danish Veterinary and Food Administration recommends a fridge temperature of no more than 5 degrees.^[1] The Swedish Food Agency advises keeping the fridge at 4 °C, having a fridge thermometer that doesn't need power, and keeping cold packs or plastic bottles of water in the freezer.^[3] The U.S. FDA recommends thermometers in both the fridge and the freezer, so you can check the temperature during a power cut.^[2]

No more than 5 °C in the fridge
A thermometer that needs no power
Cold packs or water bottles in the freezer

While the power is out

Don't open the fridge and freezer unnecessarily. That way the food stays cold for longer.^[1] If you can, note when the power went, and move frozen cold packs, frozen water bottles or food from the freezer into the fridge so it holds the cold longer.^[3]

If it is cold outside, you can put newly bought food outside in the cold, but avoid placing it directly on the ground.^[1]

How long does the freezer last?

A full freezer holds its temperature for about 48 hours, and a half-full one for about 24 hours, as long as the door stays closed.^[2] So a well-filled freezer keeps the cold longest, and it pays to leave it shut even if you are curious.

Can I refreeze the food?

If the food in the freezer still has ice crystals, or is no warmer than about 4 °C, it can be refrozen or cooked.^[2] This is where a freezer thermometer makes a difference, because then you don't have to guess.

When should food from the fridge be thrown out?

Once the power is back, the fridge should get down to no more than 5 °C. Above 5 degrees there is a risk of bacteria growing in the food, and some items may have been damaged and should be discarded.^[1] Sensitive items like fresh fish and minced meat are affected more than, say, yoghurt and cheese.^[1]

After a power cut you can use your senses and look at, smell and taste the food to judge whether it is still good.^[1] The Swedish Food Agency sets a limit for when that is enough: if the power cut lasted no more than 7 hours and the fridge started at 4 °C, or no more than 4 hours if it started at 8 °C.^[3] If it lasted longer, your senses are not enough to go by. The FDA stresses that you can't rely on appearance or smell alone.^[2]

If you are unsure about fresh fish or minced meat after a long power cut, be extra careful. Those are exactly the items that are affected most.^[1]

If the power cut is announced

If a power cut has been announced for a set period, you can plan to cool hot food at another time, or buy new chilled goods once the power is back.^[1] If you need to cool hot food, use a cold water bath so the temperature drops below 10 °C within four hours at most.^[1]

Keep food that needs no fridge

Also keep food at home that can be eaten without cooking, for example canned goods and crispbread, which need neither a fridge, a hob nor an oven.^[4] Then you don't depend on the fridge if the power is out for long. Read more in power cut: how to manage when the electricity goes.

Ready for a power cut

See what the authorities recommend your household has ready for three days.

See your checklist

For the full list of what to keep at home, read on here: Emergency supply list: what to keep at home

Frequently asked questions