Pick the right kind of backup power
| Option | Typical cost | Runs | Good for |
|---|---|---|---|
| Power bank (10,000–30,000 mAh) | $20–80 | phones for days | everyone should have one |
| Portable power station (battery + inverter, 500–3,000 Wh) | $300–2,500 | fridge for hours, CPAP overnight, lights and phones for days | quiet, safe indoors, recharge from solar or a car |
| Inverter generator (2,000–4,000 W) | $500–1,500 | fridge, freezer, lights, internet, furnace blower | quiet, fuel-efficient, clean power for electronics |
| Portable generator (5,000–10,000 W) | $600–2,000 | above plus well pump, sump pump, some 240 V loads | lots of power, loud, thirsty |
| Standby generator (natural gas or propane) | $8,000–20,000 installed | most or all of the house, automatically | long outages, medical needs, rural homes |
Many households do best with a mid-size inverter generator plus a power station: run the generator a few hours a day to cool the fridge and charge everything, and let the battery cover nights quietly and safely.
Size it to your needs
Add up what you'll run at the same time. Each appliance has a running watts number and a higher starting (surge) watts for the second it kicks on. Your generator must handle all running watts plus the single biggest surge.
Use the calculator below, or check the labels on your appliances.
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Generator safety: the big three
1. Carbon monoxide
Outside, 20 feet away, exhaust pointed away
Run generators only outdoors, at least 20 feet from the house, with the exhaust pointed away from doors, windows and vents. Never in a garage, even with the door open, or in a basement, crawl space, carport or shed. Install battery CO alarms inside. Choose a model with automatic CO shutoff if you can.
2. Electrocution and backfeeding
Never plug a generator into a wall outlet with a double-male "suicide cord." It sends power backward into the grid, where it can kill a lineman working on the lines down the street. It can also start a fire and destroy the generator when the power comes back.
There are two safe ways to power household circuits:
- Extension cords: run heavy-duty outdoor cords (12- or 10-gauge) from the generator straight to appliances. Simple and safe.
- Transfer switch or interlock kit, installed by a licensed electrician with a permit, plus an outdoor power inlet box. You then plug the generator into the inlet and choose which circuits to power. This is the right way to run a furnace, well pump or hard-wired loads.
3. Fuel and fire
- Turn the generator off and let it cool before refueling. Gasoline on a hot engine ignites.
- Keep it dry. Run it under an open canopy or generator tent — never in an enclosed space.
- Ground it according to the manual.
- Chain it to something solid. Generators get stolen in long outages.
Storing fuel
| Fuel | Shelf life | Notes |
|---|---|---|
| Gasoline | 3–6 months plain; about 1–2 years with stabilizer | Use ethanol-free if you can. Rotate into your car. Store in approved cans, in a detached shed, away from the house. |
| Diesel | about 1 year (longer treated) | Less flammable; for diesel generators. |
| Propane | doesn't go bad | Tanks stay outdoors, upright. Many generators are dual-fuel. Great for long-term storage. |
| Natural gas | piped in | Standby units only; usually keeps flowing in outages but can be shut off in earthquakes. |
A typical 3,000–4,000 W generator burns roughly 0.2–0.4 gallons an hour at half load (inverter models at the low end), so running it 10–12 hours a day takes about 2–5 gallons. Check your model's runtime chart. Running it in short bursts stretches your supply a lot.
Check your city and county rules for how much fuel you may store at home.
Keep it ready
- Run it monthly for 15–20 minutes under load (plug something in).
- Change the oil on schedule; keep a spare quart, spark plug and air filter.
- Before storing, add stabilizer and run it 10 minutes, or run it dry.
- Keep the manual, cords, oil, funnel and a flashlight in one tote with the generator.
Using your car as a generator
A running car can charge phones and power banks, or run a small inverter (300–400 W plugged into the 12 V socket). Only do this outdoors with the car in open air — never in a garage — and don't let the engine idle with snow blocking the tailpipe.
Sources: CDC — Carbon Monoxide Poisoning · CPSC — Portable Generator Safety · Ready.gov — Power Outages · Energy Saver (DOE)