WattNeeded / Guides

What size power station do you need to run a fridge and freezer for three days?

Short answer: 10,673 Wh of rated capacity — that's the 4 kWh+ — expandable system or generator territory. Serious storm prep. Pair the battery with solar or a generator at this scale.

The math, appliance by appliance

ApplianceAvg drawHours usedEnergy
Refrigerator (full-size)60 W72 h4,320 Wh
Chest freezer45 W72 h3,240 Wh
Energy needed over 72 hours7,560 Wh
÷ 0.85 inverter efficiency8,894 Wh
× 1.2 headroom (ageing, cold, overrun)10,673 Wh
Recommended: 4 kWh+ — expandable system or generator territory. Output check: 270 W continuous, 1,020 W surge.

Fridges and freezers use their average cycling draw for energy and full compressor draw for the output check — that's why the numbers differ from the label.

Adjust this in the calculator See current prices

Quick answers

Can a smaller unit than 10,673 Wh work?
The bare energy need is 8,894 Wh after inverter losses; the extra 20% covers battery ageing, cold weather, and outages running long. A smaller unit works on a good day — this size works on a bad one.
What about output watts, not just capacity?
The station must sustain 270 W continuous and survive a 1,020 W start-up surge. Nearly every unit in the 4 kWh+ clears both comfortably.
Could solar keep this running indefinitely?
Roughly 840 W of panels replaces a day's usage with ~4 hours of decent sun at real-world (75%) efficiency. Half that solar doubles your runtime instead of sustaining it.