What to Do When the Power Goes Out: Safety First, Then the Food, the Heat, and the House

Many outages are over within a few hours. The ones that matter come with a winter storm or a heat wave and run for days, and that is when people get hurt by what they bring in to fight the dark and the cold. The CPSC says more than 100 people die each year from carbon monoxide linked to portable generators. Meanwhile the food in the fridge and the pipes in the walls are on a clock.

Below: the safety rules first, then the food, the heat, the house, the restart, and getting ready for next time, drawn from Ready.gov, the CDC, the CPSC, OSHA, the Red Cross, and utility safety pages.

First Check: Is It Just Your House?

Look outside. If the streetlights and the neighbors' windows are dark too, the outage is the utility's. If only your house is dark, the cause may be inside. Southern California Edison (SCE) and Cook County, Illinois both say to check your breakers or fuses and whether the neighbors have power first.

• Only your house: check the panel with a flashlight for a tripped breaker. Our breaker guide covers resetting one safely, and the signs that mean hands off: a burning smell, scorch marks, buzzing, heat, or water near the panel. If nothing has tripped, call the utility.
• The whole street: report it to your utility by phone or its online outage map, if it has one.
• Call 911 only for an emergency: a fire, a downed line, a CO alarm, or someone sick or hurt. Baltimore's emergency management office says not to call 911 for information.

Safety Rules for the Whole Outage

Carbon monoxide

Carbon monoxide (CO) has no color or smell, and the CPSC warns that a generator used indoors can kill in minutes. In an outage, it comes from what people bring in for power, heat, or cooking:

• Generators, grills, camp stoves, and charcoal stay outside. The CDC says never to use them inside the home, in basements or garages, or near windows. For generators, the CDC and the CPSC add: not even with the doors and windows open.
• Generators run outdoors only, at least 20 feet from the house, with the exhaust pointed away from windows, doors, and vents, per the CPSC. Never in a garage, basement, crawlspace, or shed, or on a porch. Our portable generator guide covers models that shut off automatically when CO builds up.
• No gas oven or range for heat, per Ready.gov and the CDC. No outdoor stoves or heaters indoors, per the Red Cross, and fireplaces and wood stoves only if properly vented, per the CDC.
• No car running in the garage, even with the door open; the CDC says never in an attached one. To charge phones in the car, move it out of the garage and away from the house before running the engine, as the Texas Department of Insurance advises.
• CO alarms with battery power on every level. The CPSC says battery-operated alarms or plug-ins with battery backup, outside sleeping areas and on each floor. A plug-in with no battery goes dead with the power.

If a CO alarm sounds, get everyone out, pets included, call 911 from outside, and stay out until responders say it is safe. Our CO alarm guide covers what comes next.

Light: flashlights, not candles

The Red Cross, the CDC, and SCE all say to use flashlights or battery lanterns instead of candles, which are a fire hazard. If you do light a candle, the CDC says never to leave it unattended. Ready.gov suggests a flashlight for every member of the household.

Downed power lines

Assume every downed line is live, as New York State's emergency management office says, and keep everyone away from it and from anything it touches. The Red Cross says to stay at least 35 feet away; some utilities ask for more (SCE says 100 feet), so use the larger number if yours gives one. Call 911 from a safe place.

Generators: never plug one into a wall outlet

Powering the house by plugging a generator into a wall outlet is called backfeeding. The CPSC calls it extremely dangerous: it can electrocute utility workers and neighbors on the same transformer, and it bypasses some of your home's circuit protection. OSHA says never to connect a generator to a building's electrical system unless a qualified electrician has installed it with a transfer switch. Otherwise, plug appliances straight into the generator with heavy-duty outdoor cords rated for more watts than their load (CPSC). Keep it dry, since Ready.gov warns a wet generator can shock you, and let it cool before refueling.

Medical equipment that needs power

Ready.gov says to talk to your medical provider about a power outage plan for medical devices powered by electricity and for refrigerated medicines. The Red Cross says to evacuate if you have medical devices that need power, or if the house gets too hot or too cold. Some utilities, SCE among them, run programs for customers who rely on powered medical equipment; ask yours.

Keep Food Safe

Keep the refrigerator and freezer closed. The CDC and the FDA say a closed refrigerator keeps food cold for about 4 hours, and a full freezer holds its temperature for about 48 hours (about 24 if half full). Eat fresh, perishable food first, as the Red Cross suggests, and if the power may be out longer than 4 hours, the USDA says to move food into a cooler with enough ice or frozen gel packs to keep it at 40°F or below. Move milk, meat, eggs, and leftovers before the fridge has been off 4 hours, since that's when the CDC says perishables go.

• What to throw out: the CDC says to throw out perishable food in the refrigerator (meat, fish, cut fruits and vegetables, eggs, milk, and leftovers) after 4 hours without power or a cold source like ice. Ready.gov adds a temperature rule: throw away any food that has been at 40°F or higher for two hours or more, or that has an unusual odor, color, or texture. Both rules apply; whichever one the food hits first, it goes.
• The freezer: the CDC says thawed food that still has ice crystals or is at 40°F or below can be refrozen or cooked.
• Appliance thermometers in the fridge and freezer turn guessing into a decision. The CDC's targets: 40°F or below in the refrigerator, 0°F or below in the freezer.
• Never taste food to decide. When in doubt, throw it out (CDC).
• Medicine: Ready.gov says that if the power is out for more than a day, discard any medication that should be refrigerated, unless the label says otherwise. For a medicine you depend on, ask your doctor or pharmacist, as the Red Cross advises.

Stay Warm (or Cool) Safely

Most furnaces and boilers, gas ones included, need electricity to run, so the heat usually goes off with the power. Hold on to the heat you have:

• Layer up and get out the blankets, sleeping bags, and winter coats (CDC).
• Keep doors closed. The CDC says to close off rooms you aren't using and stuff towels in the cracks under doors.
• If it gets too cold, leave. Ready.gov says to go to a community location with power if the cold or heat is extreme; local officials can tell you where warming and cooling centers are open. If you leave, set the thermostat no lower than 55°F, the minimum our winter guide gives for an empty house.

Space heaters, once the power is back: keep all sides at least 3 feet from anything that can burn, plug the heater straight into a wall outlet (never an extension cord or power strip), and turn it off when you leave the room or go to sleep, per the CPSC. A battery power station is the wrong tool for heat: a 1,500-watt heater would drain even a 2,048 Wh station in under an hour and a half.

In summer heat, Baltimore's emergency management office suggests moving to the lowest level of the house, wearing lightweight, light-colored clothing, and drinking plenty of water. If the heat is intense and the outage may be long, go to a cooling center or another place with power.

Protect the House

• Pipes. In a winter storm the CDC says to let taps drip, and opening cabinet doors under sinks on outside walls lets remaining warmth reach the pipes. If a faucet slows to a trickle, follow our frozen pipes guide. A tankless water heater's freeze protection needs power, and Rinnai gives a draining procedure for prolonged outages; follow your unit's manual.
• Sump pump. It stops when the power does, often in the same storm that fills the pit. A battery backup takes over on its own; a generator helps only if someone is home to plug the pump in. Our sump pump guide compares backups.
• Electronics. Turn off or unplug the electronics and appliances you were using; Ready.gov warns that power may return with surges or spikes that can damage them. Leave one light switched on so you know when the power is back, as SCE, Baltimore, and Cook County all suggest.

When the Power Comes Back

1. Wait a few minutes, then turn things on one at a time, as Safe Electricity advises, so the circuits don't overload.
2. If part of the house is still dark, look for a tripped breaker. The Red Cross's advice is the most cautious: have an electrician inspect any tripped breakers before you turn them back on. If you reset one yourself, SCE's steps are to turn off the lights and unplug the appliances in the rooms that lost power, then switch the breaker fully off and back on once; if it trips again, leave it off and call an electrician. Don't touch the panel at all if you smell burning, see scorch marks or sparks, hear buzzing, feel heat, or see water, or if the panel or wiring got wet in the storm. Our breaker guide has the details.
3. If the furnace doesn't restart, check the thermostat, the furnace's service switch, and its breaker, then see furnace not turning on. If you smell or hear gas, leave right away without switching lights or using your phone inside, and call the gas utility from outside, as the CPSC advises.
4. Check the food with the thermometer and the rules above.
5. Test the sump pump with the bucket method in how to test a sump pump, and test the smoke and CO alarms.

Get Ready for the Next One

• List what needs power. Ready.gov says to inventory the items you rely on that need electricity and plan for batteries and other power sources.
• A flashlight for every person, spare batteries, a battery or hand-crank radio, and phone chargers or battery packs.
• Food and water: the Red Cross suggests at least two weeks of non-perishable food and water. Keep appliance thermometers and a cooler on hand, and the CDC suggests freezing containers of water and gel packs ahead.
• CO alarms with battery power on every level, tested monthly (CPSC).
• Surge protectors for electronics, and a car gas tank at least half full (Red Cross).
• Know how to release the garage door by hand (Cook County); the opener's manual shows how. Chamberlain, maker of LiftMaster openers, says to use the emergency release only when the door is fully closed, if possible, because a door with weak or broken springs can fall rapidly and without warning.

Backup power. A portable generator runs a fridge, a sump pump, and lights as long as you keep it fueled, but only outdoors, 20 feet from the house, and never backfed; a hardwired furnace or well pump needs an electrician-installed transfer switch or interlock. A battery power station burns nothing, so it can sit indoors beside the fridge or a CPAP, but a fridge alone can use most of a large one's charge in a day. Our generator guide and power station guide compare the options.

Frequently Asked Questions

How long is food safe in the fridge when the power goes out?

About 4 hours with the door closed, per the CDC and the FDA; a full freezer holds about 48 hours, a half-full one about 24. After 4 hours without power or ice, the CDC says to throw out perishables such as meat, fish, eggs, milk, and leftovers.

Can I run a generator in the garage with the door open?

No. The CDC and the CPSC say never to run one in a home or garage, even with the doors and windows open. Run it outdoors only, at least 20 feet from the house, with the exhaust pointed away from windows, doors, and vents.

Can I plug my generator into a wall outlet to power the house?

No. That is backfeeding, which the CPSC warns can electrocute utility workers and neighbors. Plug appliances directly into the generator with outdoor-rated cords, or have a licensed electrician install a transfer switch or interlock kit.

The Bottom Line

Flashlights, not candles. Generators, grills, and camp stoves stay outside, with the generator at least 20 feet from the house and never plugged into a wall outlet. Never heat with the oven, and keep battery-powered CO alarms on every level. Keep the fridge shut, unplug the electronics, and turn things back on one at a time. If the house gets too cold or too hot, or medical equipment needs power, go somewhere that has it.

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