Backup power

Start with a power audit

Before buying anything, work out what actually has to stay running. Most households need far less power than they think, as long as they choose carefully.

Make a list of essential devices with their wattage (printed on a label, in the manual, or measured with an inexpensive plug-in watt meter). Then estimate how many hours a day each one really needs to run.

• Medical equipment: oxygen concentrators, CPAP machines, powered wheelchairs, refrigerated medication.
• Communication: phones, a radio, internet equipment if it has backup power.
• Food: the refrigerator and freezer, run in cycles rather than continuously.
• Heat or cooling for vulnerable people: a furnace blower, a fan.
• Light: LED lamps and flashlights use very little power.

Running watts and starting watts

Anything with a motor or compressor (refrigerators, freezers, sump pumps, well pumps, air conditioners) draws a brief surge when it starts, often two to three times its running wattage. A generator or power station has to handle that surge, not just the running load.

Add up the running watts of everything you want on at the same time, then add the single largest starting surge. That's the minimum size to look for.

Medical devices come first

• Ask your doctor or equipment supplier how long each device runs on battery and what backup they recommend.
• Many utilities keep a medical priority or life-support list. Register so they know a household member depends on power, while remembering it doesn't guarantee faster restoration.
• Keep spare batteries charged, and know where you would go (a relative's home, a hospital) if backup power ran out.
• Ask the pharmacist how long refrigerated medicines, such as insulin, stay effective without refrigeration.

Your options, small to large

• Power banks: phone-sized batteries for charging phones, radios and headlamps. Cheap, safe indoors, and worth having several.
• Portable power stations: larger lithium batteries (rated in watt-hours) with regular outlets. Silent and safe to use indoors, and can be recharged from a wall outlet, a car or solar panels. Good for CPAP machines, lights, routers and short fridge cycles.
• Solar panels: pair with a power station to recharge during long outages. Output drops sharply in cloud, winter and shade, so size generously.
• Portable generators: the most power for the money, but they burn fuel, are loud, and must run outdoors. Inverter generators are quieter and produce cleaner power for electronics.
• Standby generators: permanently installed, start automatically, and run on natural gas or propane. They must be installed by licensed professionals.

Generator safety: carbon monoxide

Generator exhaust contains carbon monoxide (CO), a gas you can't see or smell that can kill within minutes. Most generator deaths happen when one is run in or too close to a home.

• Never run a generator indoors, or in a garage, basement, crawl space, shed or covered porch, even with doors and windows open.
• Place it outside at least 20 feet from the house, with the exhaust pointing away from doors, windows and vents, including your neighbors'.
• Install battery-powered or battery-backup CO alarms on every level and outside sleeping areas, and test them.
• If anyone feels dizzy, sick, weak or confused, get everyone into fresh air immediately and call 911.

Fuel and refueling

• Turn the generator off and let it cool before refueling. Fuel spilled on a hot engine can ignite.
• Store fuel in approved, labeled containers, outside living areas and away from fuel-burning appliances. Check local fire codes for limits on how much you can store.
• Gasoline breaks down within a few months. A fuel stabilizer extends that. Rotate stored fuel into your car before it ages.
• Run the generator for a few minutes every month or two so it starts when you need it.

Keeping food and medicine cold

Keep refrigerator and freezer doors closed. An unopened refrigerator keeps food safely cold for about 4 hours. A full freezer holds its temperature for about 48 hours (24 hours if it's half full).

Keep appliance thermometers in both. Perishable food (meat, dairy, eggs, leftovers) that has been above 40°F (4°C) for more than 2 hours should be thrown out. Food in the freezer that still has ice crystals or is at 40°F or below can be refrozen.

Heat, light and cooking without power

• Use LED flashlights and lanterns rather than candles. Candles cause house fires during outages every year.
• Never use a gas stove or oven, a grill, a camp stove or a charcoal burner to heat your home. Grills and camp stoves are for outdoor use only.
• If you have a fireplace or wood stove, have it inspected before you need it, and keep a CO alarm nearby.
• In heat, stay on the lowest floor, keep blinds closed, drink water, and know where a cooling center is. In cold, gather everyone in one room, layer clothing and close off unused rooms.
• To charge phones from a car, run the car outdoors only, never in a garage, even with the door open.

When the power comes back

Unplug sensitive electronics during the outage and plug them back in a few minutes after power returns, to avoid surges. Turn on major appliances one at a time. Check the refrigerator and freezer temperatures before eating anything from them, and when in doubt, throw it out.