How to Run a Generator Safely During a Power Outage
Carbon monoxide is a colorless, odorless gas that can kill quickly. CDC and CPSC say never to run a generator, pressure washer, or gasoline engine inside a home, basement, or garage, or less than 20 feet from any window, door, or vent. Use a battery carbon monoxide alarm near sleeping areas. If someone may have CO poisoning, get to fresh air and call 911. Poison Help is 1-800-222-1222.
Every year, people who are only trying to keep a freezer running or a room warm are killed by carbon monoxide. This page restates official placement rules from CDC, CPSC, and Ready.gov. It is not a substitute for your generator's manual or a licensed electrician.
The 20-foot outdoor rule
Outdoors means more than 20 feet from openings, with exhaust pointed away from the house. A garage with the door open is still an indoor generator.
CDC's power-outage guidance and CPSC generator-safety materials agree on the distance. Ready.gov repeats that generators and fuel should be used outdoors and at least 20 feet away from windows, doors, and attached garages. Use a heavy extension cord that can reach that far rather than pulling the machine closer to the house.
Keep the generator dry. CPSC and Ready.gov warn that touching a wet generator or devices connected to one can cause electrical shock. Let the engine cool before you refuel; fuel spilled on hot parts can ignite.
Never back-feed a generator by plugging it into a wall outlet. That can kill utility workers and start fires. Use cords to individual appliances, or a transfer switch installed by a qualified electrician.
What never becomes a heater
Never heat a room with a charcoal grill, patio grill, camp stove, or kitchen oven.
Ready.gov: never use a gas stovetop or oven to heat your home. CDC: never use a charcoal grill or camp stove indoors. Those devices produce carbon monoxide even when they look like ordinary household tools.
Install battery-powered or battery-backup carbon monoxide detectors near sleeping areas (CDC) and in central locations on every level (Ready.gov). Test them before you ever start a generator. A plug-in-only alarm goes dark when the house goes dark.
Power stations and when a generator is the wrong first purchase
Light, phone charging, and a radio often come before a gasoline generator, especially for renters.
A portable power station cannot create carbon monoxide. It has limits measured in watt-hours: watts times hours. The book walks through that math so you do not buy a box that dies before sunrise.
If you do own a generator, sketch the 20-foot placement on paper, store fuel as local fire code allows, and watch the CPSC generator-safety video linked from the book's Watch and Learn boxes. Official rules beat a neighbor's setup story.
Return to the long-outage plan or see the book.
Why carbon monoxide is different from a power problem
A dark house is uncomfortable. Carbon monoxide can make people unconscious before they understand they are being poisoned. That is why placement rules are not optional tips.
Carbon monoxide is produced whenever carbon-based fuel burns incompletely. Generators, gasoline tools, charcoal, propane camp stoves, and car engines all can produce it. You cannot see it or smell it. CDC describes symptoms that can look like flu: headache, dizziness, weakness, nausea, vomiting, chest pain, and confusion. High levels can cause loss of consciousness and death. If you suspect CO poisoning, get to fresh air immediately and call 911. For questions about exposures, the Poison Help line is 1-800-222-1222.
CPSC has spent years warning that people move generators into garages when rain starts, or place them just outside a window so an extension cord will reach. The agency’s public safety information, along with CDC’s power-outage page, is the source of the more-than-20-feet rule used in 90 Days Without Power. Ready.gov repeats the distance and adds the electrical warnings: keep the generator dry, use heavy-duty outdoor-rated cords, and never back-feed the house wiring by plugging a generator into a wall outlet.
A licensed electrician can install a transfer switch so a portable generator can power selected circuits without sending current into utility lines. That is a home-improvement project to finish before storm season, not a rainy-night experiment. If you do not have a transfer switch, run cords to individual appliances and respect the generator’s watt rating, including the higher starting watts of motors.
Refueling is a fire problem as well as a CO problem. Shut the generator down and let it cool. Store fuel in approved containers, away from living spaces and ignition sources, and only in amounts your local fire code allows. Do not store gasoline in a stairwell or beside a water heater.
Test battery carbon monoxide alarms when you change clocks or when you rotate the rest of the kit, and after any guest resets breakers. Place them near sleeping areas (CDC) and in central locations on every level (Ready.gov). Replace units that have reached the manufacturer’s end-of-life date. A chirping detector is information, not an annoyance to silence and forget.
Indoor-looking alternatives that are still dangerous, and quieter options that are not
Grills, camp stoves, and ovens are not indoor heaters. Portable power stations and battery lights cannot produce carbon monoxide, which is why they often belong earlier in a renter’s plan than a gasoline generator.
Ready.gov states plainly not to use a gas stovetop or oven to heat your home. CDC says never to use a charcoal grill or camp stove indoors. Those sentences are short because the deaths they prevent are not theoretical. A fireplace is only as safe as its flue and its intended fuel. A decorative gas fireplace has its own manufacturer rules.
If your reason for wanting a generator is “I need the phones and a radio to work,” measure that need in watt-hours and look at a power station first. If your reason is “I must run a refrigerator after the USDA four-hour window,” do the watt math and the placement sketch before you buy anything. If your reason is “I must run medical equipment,” talk to the device maker and your clinician about a labeled backup; a store generator and a household extension cord may not be an approved solution.
Watch the official CPSC generator-safety video linked from the book’s Watch and Learn boxes rather than a random social-media setup tour. Then walk your own yard and mark a spot that is more than 20 feet from openings, on a dry surface, with exhaust pointed away from the house and away from a neighbor’s window. If you cannot meet that geometry, you do not have a safe generator site.
Pair this page with staying warm without electricity and staying cool without power, because the urge to drag a machine indoors is usually a heat or cold problem in disguise. The book’s power chapter includes a placement diagram and the same official distances.
Questions people ask
Can I run a generator in the garage with the door open?
No. CDC and CPSC say never to run a generator in a garage, even with the door open, and to keep it more than 20 feet from windows, doors, and vents.
Who do I call if I think someone has carbon monoxide poisoning?
Get to fresh air and call 911. Poison Help is 1-800-222-1222.