Freezer autonomy
Calculate how long frozen food lasts without electricity and what to do.
Autonomy calculator
General rules
Full freezer
A completely full freezer keeps food frozen for up to 48 hours without electricity, as long as the door stays closed. Frozen items act as ice blocks, keeping the temperature low for longer.
Half-full freezer
A freezer at half capacity keeps a safe temperature for 24 hours. Less frozen mass means less thermal inertia. Tip: keep frozen water bottles to fill empty spaces.
What to do during a power outage
Golden rule: do NOT open the door!
Every time you open the freezer you lose approximately 4 hours of autonomy. Resist the temptation to check. If you need something, open quickly, take what you need and close immediately.
Tips to maximise duration
- Cover the freezer with blankets or quilts for extra insulation
- Group frozen items together (more mass = more cold)
- Place ice packs or frozen water bottles in empty spaces
- If you have two freezers, consolidate everything into one
- Avoid opening the door unnecessarily
When to discard food
Food safety
- Meat, fish, seafood: if above 4 degrees C or thawed for more than 2 hours, THROW AWAY
- Cooked vegetables: if fully thawed, do not refreeze
- Bread, cakes: safe to refreeze if they still have ice crystals
- Ice cream: if softened, throw away (do not refreeze)
- Fruit: safe to refreeze if it still has ice crystals
- General rule: if it has ice crystals and is below 4 degrees C, it can be safely refrozen