What Size Generator for a Freezer?
A 2,200W inverter covers a chest or upright freezer with room to spare: plan on 500 running watts and a 1,500W compressor start. Run the fridge beside it and you're at a 3,400W inverter. The full combos are in the table.
Wattage by type
| Freezer type | Running | Starting |
|---|---|---|
| Chest freezer, 7 cu ft | 100 to 350 W | 500 to 1,000 W |
| Chest freezer, 15 cu ft | 200 to 400 W | 700 to 1,200 W |
| Planning number | 500 W | 1,500 W |
| Upright, frost-free | 300 to 600 W | 1,000 to 1,800 W |
| Old upright | 600 to 800 W | 1,800 to 2,400 W |
What it takes with company
Same engine as the wattage picker: running total plus the single biggest start spike, then the smallest class that carries it with 20% headroom.
| Load list | Running | Peak | Buy |
|---|---|---|---|
| Freezer alone | 500 W | 1,500 W | 2,200W inverter |
| Freezer + fridge | 1,200 W | 2,700 W | 3,400W inverter |
| Freezer + fridge + the basics | 1,400 W | 2,900 W | 3,400W inverter |
The details that change the answer
A freezer full of meat is the appliance people actually buy the generator for, and the good news is it's one of the cheapest loads on the list. Chest freezers especially: the cold stays put when you open the lid, the compressor is small, and a modern 15 cu ft chest unit runs under 400W. Frost-free uprights cost more watts because the defrost heater (300 to 500W of pure resistance) kicks in on a timer and adds itself to whatever else is running.
The clock is generous. A full chest freezer holds zero-ish for about 48 hours closed, 24 if half full (FDA figures). So the strategy for a long outage is rotation, not continuous power: two hours of generator in the morning and evening keeps a freezer frozen indefinitely and leaves the rest of the fuel for the furnace and the phones. Tape the lid shut if teenagers live with you.
Questions people ask
How long will a freezer stay frozen without power?
About 48 hours if it is full and stays closed, about 24 half-full, per FDA guidance. A chest style beats an upright because the cold air does not fall out the door. If the outage will outlast that, run the generator on it two hours out of every eight or so rather than continuously.
Can one small generator run the fridge and freezer together?
Yes. Both planning numbers together are 1,200 running watts, and the worst single start spike (the fridge, 1,500 extra) puts the peak at 2,700W, which a 3,400W inverter covers with headroom. They will rarely start in the same second, but size as if they can, because eventually they will.