What size generator do I need to run a refrigerator and freezer?
Short answer: 1,000–1,500 watts, and the smallest inverter generator you can buy covers it. Here's the math so you can check your own units.
The numbers that matter
| Load | Running watts | Starting (surge) watts |
|---|---|---|
| Modern refrigerator, 20 cu ft, Energy Star | 150 | 600 |
| Older fridge or 25+ cu ft | 300–400 | 1,000–1,300 |
| Chest freezer, 10–15 cu ft | 200 | 600 |
| Upright freezer with auto-defrost heater | 350 | 900 |
Add the running watts of everything on at once: a modern fridge + freezer is about 350 W. The surge trap: if both compressors start at the same instant — which happens after a power cut restores — the worst case is roughly 1,200 W for under a second. That's the number your generator's surge rating must cover, and any 1,000 W+ inverter generator handles it.
Why an inverter model specifically
Compressor motors are inductive loads. Conventional generators produce adequate power but with dirtier sine waves and higher total harmonic distortion (THD), which stresses the fridge's control board on newer units. Inverter generators hold THD under ~3% — clean enough for electronics — and throttle down at light load, which is exactly what a fridge-only setup is.
The duty-cycle trick: run it twice a day
Food safety rules from USDA guidance: an unopened fridge stays below 40°F for about 4 hours, and a full freezer holds temperature for 48 hours. So during an outage you don't need 24/7 power — run the generator roughly 2 hours in the morning and 2 in the evening and everything stays cold indefinitely.
Fuel math for that schedule with a 2,000 W inverter generator (~0.3 gal/hr at the ~25% load a fridge presents): about 1.2 gallons a day. A 5-gallon can runs the food for four days. Add a 20 lb propane tank on a dual-fuel unit and you're covered a week without refueling gasoline.
The 2,000 W dual-fuel inverter class is the sweet spot for this job — quiet enough for a neighborhood, sips fuel, runs gas or propane.
Where battery power wins outright
A fridge and freezer are the ideal battery-bank load: small, steady, and worth protecting silently overnight. A single 100 Ah LiFePO4 battery (1,280 Wh, ~80% usable) through an 85%-efficient inverter runs a fridge/freezer pair for 20+ hours. Two batteries plus a small solar panel make the fuel question disappear for this job. Size that setup with our battery bank sizer, or run both loads plus the well pump with the generator size calculator.
FAQ
Can I run my fridge off an extension cord?
Yes — use a 12-gauge outdoor cord rated for the load, kept as short as practical. Never back-feed the house through a dryer or wall outlet; that's a transfer-switch job and a code and safety violation.
What about the ice maker and defrost cycle?
Auto-defrost heaters add 300–500 W when they cycle. On a 2,000 W generator with a freezer also plugged in, a simultaneous defrost + compressor start can trip the breaker. Some fridges let you disable the defrost timer — worth doing during an outage.
Does the freezer need its own generator?
No. A full freezer barely runs — it's already at temperature. One right-sized generator, run on the twice-a-day schedule, protects both.