Capability · What you can do · 6 min read
Keep the fridge cold in a power cut
Keep the doors shut and the clock in mind: a fridge stays cold for up to four hours in a power cut, and a full freezer stays frozen for up to 48 hours, 24 if it’s half full (Food Standards Agency, checked 26 Aug 2026). Here’s how to stretch both.
First move: shut the doors and leave them shut
The FSA’s advice starts where you should: “keep fridge and freezer doors closed as much as possible”. Every opening dumps the cold air you’re trying to keep. Citizens Advice puts the same point positively: the longer you keep a fridge or freezer door closed during a power cut, the longer it stays cold.
So decide once. Note the time the power went off, agree with the household that the doors stay shut, and put a strip of tape across them if children forget. You are not managing the fridge now, you are managing the clock.
Know how long you’ve got
The FSA’s figures, with the doors kept shut:
| Appliance | Stays safe for | The detail |
|---|---|---|
| Fridge | Up to 4 hours | Normally at 5 °C or below; in a power cut, under 8 °C is tolerable |
| Freezer, full | Up to 48 hours | Food stays frozen with the door kept closed |
| Freezer, half full | Up to 24 hours | Less frozen mass means a faster thaw |
The rule that follows: if the fridge temperature rises to 8 °C and above, eat the food that normally needs refrigeration within 4 hours, or let it go. Fridges and freezers vary by make and model, so the FSA calls these estimates, not guarantees. For everything beyond the kitchen when the power goes off, see what to do in a power cut.
Group the frozen food and fill the gaps
Notice what the FSA’s own numbers tell you: a full freezer lasts twice as long as a half-empty one, because frozen food keeps frozen food cold. Put that to work. Push everything together into as few drawers as possible so the frozen mass acts as one block.
Do the preparation version today, while the power is on. Citizens Advice suggests filling plastic bottles with water and adding them to the gaps in your freezer to help keep it colder for longer. A freezer full of food and ice bottles is a 48-hour freezer; the bottles double as drinking water once thawed, and as cool-box blocks.
Eat in the right order: fridge, then freezer, then tins
Work through the house in order of urgency. First the fridge, inside its 4-hour window: milk on cereal, yoghurts, the leftovers, the things children will ask for anyway. Then the freezer as it starts to surrender: the FSA says fully defrosted food should be used within 24 hours, and you can freeze food again once cooked, though you’ll only be able to reheat it once after that.
The cupboard comes last, because tins don’t care how long the power is off. That is exactly why your emergency food shelf is built from ready-to-eat tins. One safety line if you’re cooking your way through the freezer: never use a camping stove, barbecue, patio heater or generator indoors, in a garage or in a tent. They produce carbon monoxide, which the NHS notes has no taste or smell.
When the power comes back: what to bin
Check the fridge thermometer if you have one, and apply the FSA’s rules rather than your nose. Fridge food that has been at 8 °C or above for more than 4 hours goes in the bin. Freezer food that fully defrosted more than 24 hours ago goes too. Food that is still cold, or still holding ice, is in play.
For anything in between, the old kitchen rule is the right one: if in doubt, throw it out. A binned yoghurt costs pence; food poisoning costs a week. Losing a full freezer feels worse, which is what the next section is for.
Will insurance pay for a freezer full of food?
Sometimes. Citizens Advice warns that a home contents policy “may not cover the contents of a freezer”, so check your policy wording for freezer contents or food-in-freezer cover before you need it, and note any single-item limit. If it’s there, photograph what you throw away and keep the receipts for replacements.
Separately, Citizens Advice notes you might be able to claim money from your electricity network operator after a power cut, depending on its cause and length. Call 105, the free power cut number for England, Scotland and Wales, to report the cut and ask; the compensation route is covered in how long a fridge lasts without power.
Cool boxes and cold windowsills
A cool box earns its keep in the first hours. Load it with those frozen water bottles and move the most vulnerable fridge items in: milk, opened jars, children’s medicines that say refrigerate (check the label’s storage range first). That buys calm without opening the big doors every ten minutes.
In winter, a garage, porch or shaded windowsill is cold, but it is not a fridge: the temperature is uncontrolled and can swing. Use it for drinks, butter, unopened jars and cans, and keep meat, fish and dairy to the FSA timings above no matter how frosty the morning looks.
Frequently asked questions
How long does food last in the fridge without power?
Up to 4 hours with the door kept shut, according to the Food Standards Agency. After that, if the temperature has reached 8 °C or above, eat food that normally needs refrigeration within 4 hours or throw it away. Appliances vary, so treat the figures as estimates.
How long will a freezer last in a power cut?
Up to 48 hours if it’s full and the door stays shut, or 24 hours if it’s half full, says the FSA. That’s why it pays to keep the freezer well stocked and to fill spare space with bottles of water before a storm is due.
Can I refreeze food that has defrosted?
Not raw. The FSA’s advice is to use fully defrosted food within 24 hours, and you can freeze food again once you have cooked it, though after that you’ll only be able to reheat it once. So cook the defrosting mince, then decide whether to eat it or refreeze it.
Should I open the fridge to check on it?
No. Keeping the doors closed is the single most effective thing you can do, per the FSA and Citizens Advice. Opening the door to peer at the milk spends the very cold you’re rationing. Note when the power went off, keep the doors shut, and work from the clock.
Does home insurance cover a freezer full of spoiled food?
Check your policy: Citizens Advice warns contents policies may not cover freezer contents, though some include it or offer it as an add-on. You may also be able to claim from your network operator depending on the cause and length of the cut. Dial 105 to report and ask.
Is food still safe if it has ice crystals in it?
The FSA’s test is time, not appearance: fully defrosted food should be used within 24 hours. Food that is still partly frozen is still inside that process. If something has clearly been warm and wet for an unknown time, apply the kitchen rule: if in doubt, throw it out.
Sources & review
- Food Standards Agency: Food safety in a power cut. Checked 26 August 2026. Fridge 4-hour figure, freezer 48/24-hour figures, 5 °C and 8 °C thresholds, doors-closed advice.
- Food Standards Agency: How to chill, freeze and defrost food safely. Checked 26 August 2026. Use fully defrosted food within 24 hours; refreeze only once cooked; reheat once.
- Citizens Advice: Prepare for a power cut. Checked 26 August 2026. Water-bottle tip, doors-closed advice, network operator compensation.
- Citizens Advice: Household contents insurance. Checked 26 August 2026. Freezer contents may not be covered; single-item limits.
- NHS: Carbon monoxide poisoning. Checked 26 August 2026. Carbon monoxide does not have any taste or smell.
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