What size generator runs a refrigerator?

Keeping food cold is the most common reason people buy a generator. The good news is that a refrigerator is a modest load once it is running. The catch is the compressor’s start-up surge.

Typical refrigerator wattage

Champion Power Equipment’s wattage chart lists a household refrigerator at 150 to 400 running watts and 800 to 1,200 starting watts. Virginia Cooperative Extension’s appliance guide lists a frost-free 16-cubic-foot refrigerator at a nameplate rating of about 725 watts. Nameplate figures are maximums, often including a defrost heater, so they run higher than typical use.

Newer, efficient models are usually at the low end; older fridges, side-by-sides with ice makers, and garage fridges in hot spaces tend to run higher.

Read your own label

Look inside the fresh-food compartment, on the side wall, or behind the kick plate at the bottom. The sticker lists volts and amps (for example, 115 V, 6.5 A). Multiply to estimate maximum watts: 115 × 6.5 ≈ 750 W. That is a conservative figure for generator sizing.

Smallest generator that works

For a refrigerator alone, the generator must supply the starting surge. With a surge up to about 1,200 watts, a generator with a starting rating of at least that and a running rating comfortably above the fridge’s running draw will work. Small inverter generators in the 2,000-watt class generally handle one refrigerator plus lights and phone charging, provided you do not start the microwave at the same moment the compressor starts.

If you also want a chest freezer, add its running watts (Champion: 100 to 500) and remember that its compressor may start while the fridge is running. The calculator adds only the largest surge, which reflects that motors rarely start at the same instant, but if you are close to the limit, a little extra margin helps.

You do not need to run it all day

FoodSafety.gov advises that a refrigerator keeps food safe for about 4 hours if the door stays closed, and a full freezer about 48 hours (24 hours if half full). Many households run the generator for a couple of hours at a time to pull the fridge and freezer back down, then shut it off to save fuel. A cheap appliance thermometer inside the fridge tells you when to run it again: the target is 40°F or below.

Tips for running a fridge on a generator

• Plug the refrigerator directly into the generator with a heavy-duty outdoor cord rated for the load, or run it through a transfer switch.
• Start the generator, let it stabilize, then plug in the fridge before other loads.
• If your fridge has electronic controls, an inverter generator gives cleaner power, though most modern refrigerators run fine on conventional generators too. See inverter vs conventional.
• Throw out perishable food that has been above 40°F for more than 2 hours, per FoodSafety.gov.

Bottom line

One refrigerator: a generator that can start at least about 1,200 watts and run several hundred watts continuously. Fridge plus freezer plus lights: aim for about 2,000 to 3,500 running watts depending on the models. Check your labels, then confirm with the calculator.