What size generator do I need for a refrigerator and freezer?
A refrigerator and a chest freezer together need a generator rated about 1,700 running watts. That is a small generator. The Champion 2500-Watt Ultralight Inverter handles both.
If you want the fridge, freezer, lights, wifi, and phone chargers running at once, the requirement rises to 2,500 running watts once you account for the compressor surge.
How many watts do a refrigerator and freezer use?
Running watts are what the appliance draws continuously. Starting watts (also called surge watts) are the brief spike a motor needs for a second or two when it starts. Needs alone is what that appliance requires by itself. With basics adds a refrigerator, a chest freezer, 20 LED bulbs, wifi, and phone chargers, which together draw 720 running watts and 1,620 peak.
Both need figures are the peak load with a 20% safety margin, rounded up to the nearest 100W. The recommended class is the smallest generator whose continuous rating covers the with-basics figure.
Refrigerator (full-size)
- Running watts
- 300W
- Starting watts
- 1,200W
- Needs alone
- 1,500W
- With outage basics
- 2,400W
- Recommended class
- 3,600W or more
Chest Freezer
- Running watts
- 150W
- Starting watts
- 600W
- Needs alone
- 800W
- With outage basics
- 2,200W
- Recommended class
- 3,600W or more
How long does food stay safe in an outage?
Food safety is the real deadline here, and it is shorter than most people guess. According to the CDC:
- Refrigerator: 4 hours with the door kept closed
- Full freezer: 48 hours
- Half-full freezer: 24 hours
A full freezer holds cold far better than a half-empty one, because the frozen food itself is the thermal mass. If you expect a long outage, filling empty space with frozen water bottles buys you time.
The number to judge by is temperature, not hours. A refrigerator should sit at 40 degrees Fahrenheit or below. If you keep an appliance thermometer inside, you can check it directly instead of guessing, and the CDC's advice is to throw out refrigerated perishables after 4 hours without power or a cold source. Never taste food to decide whether it is safe.
How is this calculated?
Two rules decide everything on this page:
- Total running watts must stay under the generator's continuous rating.
- Total running watts plus the single largest surge must stay under the generator's peak rating.
For the second rule you add only the largest surge, not every surge, because appliances rarely start at the same instant. We then add a 20% margin so the generator is not running flat out.
Appliance wattages are typical values for common residential models. Your specific appliance may differ. The nameplate on the appliance itself is always the better number.
What else should you know before you buy?
- The compressor surge is what you size for. A full-size refrigerator draws about 300 watts running and 1,200 watts to start. A chest freezer goes from 150 running to 600 starting. The running watts are almost nothing, so the surge is what decides the generator.
- Both starting at once is the risk, not the steady draw. Sizing assumes only the largest surge happens at any instant. If the fridge and freezer compressors happen to start together, the total spike is higher. Adding a little headroom covers that.
- A small inverter is enough, and it is quieter. Because the running load is so low, a small inverter generator runs both appliances for hours on very little fuel at roughly conversation-level noise.
- Do not plug a refrigerator into a generator that is already loaded. Start the generator first, let it stabilize, then add the fridge as the first appliance so its surge has the whole unit available.
Add up your own appliances
Pick what you want to power and get your exact size, with the math shown.
Open the Generator Size Calculator →Frequently asked questions
What size generator do I need to run a refrigerator and freezer?
About 1,700 running watts for both together. That is small enough that even a compact inverter generator handles it. Adding the usual outage loads brings it to roughly 2,500 watts.
Can a small generator run a refrigerator?
Yes. A full-size refrigerator draws only about 300 watts running, though it needs around 1,200 watts for the moment the compressor starts. The starting watts are what to size for.
How long will food stay safe in an outage?
The CDC says 4 hours for a refrigerator with the door kept closed, 48 hours for a full freezer, and 24 hours for a half-full freezer. Keep the doors shut and check the temperature rather than guessing. Throw out refrigerated perishables after 4 hours without power or a cold source.
Should I plug the refrigerator in first?
Yes. Start the generator and let it stabilize, then add the refrigerator before other appliances so its compressor surge is not competing with loads that are already running.
Will a generator damage my refrigerator?
A conventional generator produces power that is fine for a refrigerator. Inverter generators produce cleaner power and are a safer choice for anything with sensitive electronics, including modern fridges with digital controls.
Related
- Generator size calculator (add up your own appliances)
- Appliance wattage chart (running and starting watts)
- What will a 7,500 watt generator run? (a full worked example)
- Portable vs standby generator (which type fits your situation)
Last reviewed September 2026. Appliance wattages are typical residential values and may differ from your specific models.