What's the most practical, low-cost way to provide backup power for a single refrigerator?

Short answer

For most homeowners, the most practical, low-cost way to keep a single refrigerator running during outages is a small 2000-watt class inverter generator (typically 1800W running/2200W peak) paired with a heavy-duty 12-gauge outdoor extension cord. Run the generator only as needed (for example, 15–30 minutes each hour) to maintain safe temperatures. This setup is affordable, reliable, and easy to deploy safely.

Why this works (and what your fridge actually needs)

• A typical modern full-size refrigerator uses about 100–200 watts while running, but needs a brief startup surge of 600–1200 watts when the compressor kicks on. Mini-fridges are lower; older or larger units may be higher.
• A 2000W inverter generator provides clean power (pure sine wave) that compressors and control boards like, and the surge capacity to start the motor smoothly.
• Intermittent operation saves fuel while keeping food cold, especially if you keep the doors closed and add thermal mass (e.g., frozen water bottles).

Sizing example
- Fridge running: 150W
- Startup surge: ~800W
- Recommended generator: ≥1800W running / ≥2200W surge
- 12 AWG (12/3) outdoor extension cord ≤50 ft to minimize voltage drop

What you’ll need

• 2000W class inverter generator (quiet type; 1800W running / 2200W surge). Estimated cost: $400–$700.
• 12-gauge (12/3) outdoor extension cord, ideally ≤50 ft, with a single-outlet end. $30–$60.
• Fuel can with fresh gasoline and fuel stabilizer. $15–$30 plus fuel.
• Optional but helpful:
  • Plug-in watt meter (Kill A Watt-type) to verify draw. $25–$35.
  • Cable lock/chain to secure generator. $15–$40.
  • Battery-powered CO alarms for the home. $20–$40.
  • Generator cover/tent canopy designed for running in rain.

Step-by-step: Generator backup for a single fridge

1. Verify refrigerator load

   • Plug a watt meter between the fridge and wall for a day to confirm running watts and note the highest surge reading if available.
   • If you can’t measure, assume 150–200W running and up to 1000W surge for a standard full-size fridge.

2. Place the generator safely

   • Move it outdoors, at least 20 feet from doors, windows, and vents; exhaust pointed away from the house.
   • Never run in a garage, carport, or near open windows. Use a generator-rated rain cover if needed.

3. Connect using a proper cord

   • Use a 12-gauge outdoor extension cord directly from the generator to the fridge’s plug. Avoid daisy-chaining cords.
   • Do not backfeed your panel with a “suicide cord.” If you want whole-circuit backup later, install a transfer switch or interlock kit.

4. Start and test

   • Start the generator with no load connected. Let it warm for a minute.
   • Plug in the fridge. Listen for the compressor to start. The generator should not bog down.
   • Check the fridge interior after 30–60 minutes to confirm it’s cooling normally.

5. Run time strategy

   • In moderate ambient temps with doors closed, run the generator 15–30 minutes per hour to hold safe temperatures. In hotter weather or during frequent door openings, increase runtime.
   • Keep a cheap fridge/freezer thermometer inside to monitor temps (fridge ≤40°F / 4°C, freezer 0°F / −18°C).

6. Fueling and maintenance

   • Shut off and let cool before refueling. Use fuel stabilizer for storage, rotate fuel every 3–6 months, and exercise the generator monthly for 10–15 minutes.
   • Check oil per the manual; many small units need oil checks every 20–50 hours.

Alternate low-cost option: Battery + inverter (short outages)

If outages are typically under 6–12 hours and you want quiet, a DIY battery setup can bridge short gaps, but it’s usually more expensive than a small generator for long outages.

What to use:
- 100Ah LiFePO4 battery (≈1200Wh usable). $250–$400.
- 1000–1500W pure sine wave inverter with low idle draw. $150–$300.
- 2 AWG battery cables, 100–150A fuse/breaker, lugs, and a safe enclosure. $50–$100.

Runtime estimate:
- If your fridge averages 60–80W over time (duty cycle considered), a 1200Wh battery can deliver ~10–16 hours. Heavier loads or door openings reduce that.

Important notes:
- Use a pure sine wave inverter to protect the compressor.
- Fuse the positive lead close to the battery.
- Keep wiring short and heavy-gauge.
- To recharge, you’ll need AC power or solar; this is why multi-day outages favor a small generator.

Safety considerations

• Carbon monoxide: Place generators outdoors only. Install CO alarms in living spaces.
• Electrical: Use 12-gauge cords to minimize voltage drop and heat. Avoid overloading outlets. Keep cords fully uncoiled.
• Weather: Use a proper generator rain cover; never place on a wet surface. Elevate slightly to avoid puddles.
• Fuel: Store gasoline in approved cans, away from ignition sources. Let the generator cool before refueling.
• Power quality: Prefer inverter generators or pure sine inverters for compressor health.

Tips for best results

• Pre-chill before storms: Set the fridge/freezer one notch colder a few hours before the outage window.
• Add thermal mass: Freeze water bottles or jugs to help stabilize temps.
• Door discipline: Open the fridge as little as possible.
• Label the fridge cord: So you can quickly move between wall and generator without confusion.
• Lock it down: Use a cable lock if the generator is visible from the street.

Common mistakes to avoid

• Buying a non-inverter generator that struggles with surge or produces dirty power, leading to compressor stress.
• Using thin or long extension cords (14/16 AWG), causing voltage drop and overheating.
• Backfeeding the house via a dryer outlet—this is dangerous and illegal.
• Running the generator in a garage with the door open—still unsafe for CO.
• Letting fuel go stale; the carburetor gums up and the unit won’t start when you need it.

When to call a pro

• If you want to power the fridge from your home’s circuit without running a cord, have a licensed electrician install a transfer switch or panel interlock with an inlet. Expect $400–$1200 depending on scope.
• If you live in a condo/apartment with generator restrictions, ask a pro about indoor-safe battery power stations sized correctly for your fridge’s surge and duty cycle.

Cost snapshot

• Inverter generator + cord + fuel: ~$500–$800 upfront, a few dollars of fuel per day at intermittent runtime.
• DIY battery + inverter: ~$450–$800 for short outages, plus charger/solar if needed.

For most households, the 2000W inverter generator plus a 12-gauge cord is the best balance of cost, reliability, and simplicity. Test your setup on a calm day so you’re ready when the lights go out.