Chest freezer power outage: how long the cold lasts and what applies afterwards.
A power cut or a fault in the chest freezer in the cellar is usually noticed only when everything has started to thaw. This guide shows how long a freezer can hold its cold, what to do during an outage and what applies to food that has partly thawed. Pick your country and you see only what the authorities there recommend.
- Keep it closed: do not open the door or lid. A well-filled freezer holds the cold longer.
- How long: there is no general figure. The instruction manual gives the “storage time during a fault” for your appliance.
- Afterwards: food that is still frozen can stay in storage. Food that has partly thawed should be used quickly, raw meat, poultry and fish heated through, thawed ice cream discarded. If in doubt, throw it out.
- Switzerland: the BWL advises not to refreeze food that has thawed but to use it quickly.
- The same everywhere: you often notice the outage only when the food is already soft, and then you do not know how long it was warm.
- Frigo during a power cut: the connectivity unit keeps running for about four hours on its built-in battery.
Who this guide is for
- Households with a chest freezer or upright freezer in the cellar, garage or holiday home
- Anyone who freezes provisions, home cooking or game
- Anyone away on holiday or over the weekend
Different rules apply to restaurants and retail, see the guide to cold room monitoring. If you freeze game, the limits for cooling before freezing are in the guide to how to cool game meat. How cold the fridge should be is covered in the guide How cold should your fridge be?.
How long does the cold last without power?
There is no fixed figure. The German Federal Institute for Risk Assessment (BfR) writes that freezers can keep frozen food sufficiently cold for many hours during a power cut, provided they are well filled and are not opened, at least during the first hours. As a rough guide, the Austrian magazine Konsument gave the following figures in 2010, measured until the food had warmed from −18 °C to −9 °C:
| Appliance | Guide |
|---|---|
| Chest freezer | about 30 hours |
| Upright freezer | for many appliances after only about ten hours |
| Your appliance | value under “storage time during a fault” in the instruction manual |
The figures come from a 2010 report and may differ for newer or other appliances. Rely on the manufacturer's figure for your appliance.
What you can do during an outage
- Keep it closed. Every opening lets cold escape, even if you only want to look.
- Note the start. Without a time you cannot judge afterwards how long the appliance was warm.
- Read the manufacturer's figure. “Storage time during a fault” in the instruction manual.
- Store outside only in an emergency. In cool outdoor temperatures food can stand on a balcony or terrace for a short time, well packed and protected from contamination, animals and sun. The German Frozen Food Institute advises against longer storage outside.
- Check once power returns. The condition of the food decides, see below.
Would you notice before the food turns soft?
Get your setup →Partly thawed: what applies to the food?
The following statements are guidance from authorities and consumer organisations, not regulations. What matters is how far the food has thawed and what it is.
| Condition | Guide |
|---|---|
| Still frozen solid | Can stay in storage. |
| Soft outside, core frozen | Quality may suffer, a health risk is not necessarily present. |
| Partly thawed, cooked or plant-based | Store chilled at no more than 7 °C and use soon, or refreeze. |
| Partly thawed, raw animal products | Heat meat, poultry and fish through completely. Chilled storage or refreezing is possible afterwards. |
| Ice cream | Thawed ice cream should be discarded. |
| Fully thawed and warm | Use or discard. If in doubt, discard. |
The bodies do not all recommend the same. The German Frozen Food Institute, an industry association, names the routes above for refreezing after heating. The Swiss BWL advises instead not to refreeze thawed food but to use it quickly. If you want to be safe, follow the stricter line.
If temperature and duration can no longer be traced, consumer organisations advise throwing the food out if in doubt.
Austria: Konsument and the Ministry of the Interior
What the bodies say
- Konsument (VKI): if the food has not partly or fully thawed there are no problems. Food that has partly thawed must be cooked before it is refrozen. Food that has fully thawed and is warm has to be used or discarded. The appliance should stay closed as far as possible until the service technician arrives.
- Federal Ministry of the Interior: freezers are designed for outages of a few minutes or hours. The chest freezer should not mainly serve as a stock for a blackout, the stock should be kept mostly without electricity.
Germany: BfR and the Frozen Food Institute
What the bodies say
- BfR: when food partly thaws, quality and minimum shelf life may suffer. Raw animal foods should first be heated through completely after thawing, after which refreezing is possible once fully cooled. Thawed ice cream should be destroyed.
- Temperature: under the German ordinance on frozen foods (TLMV), deep-frozen foods must be at −18 °C or colder. On a household temperature deliberately raised to −12 °C, the BfR writes that this poses no health hazard but that quality and shelf life may suffer.
- German Frozen Food Institute: the advice on refreezing and on short-term storage outdoors is in its press release of 14 January 2026.
Switzerland: Canton of Zurich and the BWL
What the bodies say
- Canton of Zurich: keep fridges and freezers closed as far as possible. After six hours without power the fridge should be emptied, the freezer only after 24 hours.
- BWL: frozen food counts as part of the emergency stock because it can still be eaten without problems after a power cut. Food that has thawed should not be refrozen but used quickly.
Both are recommendations, not regulations for private households.
Where a manual check leaves gaps
- Cellar, garage, holiday home. You rarely look in there.
- Holiday and weekends. An outage on the first day is noticed only on your return.
- Lid not latched, plug pulled. The appliance may still run but does not cool enough.
- A creeping fault. The appliance runs, but the temperature slowly rises.
- No record. Without a history you do not know whether or how long the food was warm.
What a sensor adds
A sensor measures around the clock, alerts the people you name as soon as the temperature leaves your limit, and writes every deviation with start, end and duration to a continuous record. You can then see whether and for how long it was warm, instead of guessing.
Important: Frigo measures the air temperature at the sensor's location, not the core temperature of the food. It does not cool anything and does not save frozen food, it alerts you earlier.
If power fails, the connectivity unit keeps running on its built-in battery for about four hours. During that time Frigo keeps measuring and alerts you when the temperature leaves your limit, as long as the mobile network is available. Once the battery is empty, Frigo reports that the connectivity unit has stopped sending data. The sensors do not store readings, so there is no data for that period. New readings arrive once the connectivity unit has power again. For cases that affect only the appliance, such as a pulled plug, an open lid or a fault, Frigo alerts you without this time limit.
How the system is built is explained under How does Frigo work?.
Four things to set per appliance
- the target value, for example −18 °C
- the limit at which an alert is sent
- who is notified, including at night and on holiday
- who checks on site and what to do then
Frequently asked questions
How long does a chest freezer hold its cold without power?
It depends on the appliance and how full it is. In 2010 Konsument gave about 30 hours until −9 °C for chest freezers and about ten for many upright freezers. The BfR speaks of many hours if the appliance is well filled and stays closed during the first hours. The instruction manual gives the value for your appliance under “storage time during a fault”.
May I refreeze food that has partly thawed?
The recommendations differ. The German Frozen Food Institute names refreezing after chilled storage at no more than 7 °C for cooked dishes and raw plant-based foods, raw animal products should first be heated through completely. The BWL in Switzerland advises not to refreeze thawed food but to use it quickly. Thawed ice cream should be discarded.
Should I open the freezer during a power cut to check?
No. The BfR names as a condition that the appliance is not opened, at least during the first hours. Every opening lets cold escape.
How warm may it get in the freezer?
Under the German ordinance on frozen foods, deep-frozen foods must be at −18 °C or colder. The BfR relates its statement on −12 °C to a household temperature deliberately set higher: no health hazard, but quality and shelf life may suffer. That does not apply to food that has thawed.
Does Frigo work during a power cut?
Yes, for a limited time. The connectivity unit has a built-in battery and keeps running for about four hours during a power cut. During that time Frigo keeps measuring and alerts you when the temperature leaves your limit, as long as the mobile network is available. Once the battery is empty, Frigo reports that the connectivity unit has stopped sending data. The sensors do not store readings, so there is no data for that period. New readings arrive once the connectivity unit has power again. For outages that affect only your appliance, Frigo alerts you without this limit.
Does Frigo replace my own judgement of the food?
No. Frigo measures the air temperature at the sensor's location, not the core temperature of the food, and replaces neither your judgement nor the advice of the manufacturer or the authorities.
Sources
- German Federal Institute for Risk Assessment (BfR): Correct cooling of food in private households (FAQ, 13 Feb 2023, Germany, in German)
- German Frozen Food Institute: Power cut? What to do with frozen products (press release, 14 Jan 2026, Germany, in German)
- Konsument (VKI): Freezers (15 Sep 2010, Austria, in German)
- Konsument (VKI): Freezers, storage time during a fault (25 Aug 2003, Austria, in German)
- Federal Ministry of the Interior: Behaviour during a blackout (as of 16 Feb 2026, Austria, in German)
- Canton of Zurich: Leaflet on power cuts (Switzerland, in German)
- Federal Office for National Economic Supply (BWL): Sound advice, emergency stock (Switzerland, in German)
- Verbraucherzentrale Niedersachsen: Food during a power cut (4 Aug 2026, Germany, in German)
Your freezer in view
See a deviation before the food turns soft, and have the record automatically.
To private use →This article is guidance, not legal advice and not health advice. It reproduces recommendations from authorities and consumer organisations, which can differ, and replaces neither the manufacturer's information nor your own judgement. If in doubt, discard the food. Frigo measures the air temperature at the sensor's location, does not cool anything and does not save frozen food. Alerts require a working connection. During a power cut the connectivity unit keeps running on its built-in battery for about four hours, after that Frigo reports that the connectivity unit has stopped sending data. Sources as of: October 2026.