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Generator safety: carbon monoxide, placement and fuel

Portable generators cause preventable deaths every storm season. These are the rules that matter most.

By Wattstanding Editorial · Updated 30 Sep 2026

The short answer

Never run a generator inside a home, garage, basement or shed, or near doors, windows and vents. Exhaust contains carbon monoxide, which can kill in minutes and gives little warning. Use battery-powered CO alarms indoors and a licensed electrician for any house connection.

Carbon monoxide

SafetyCarbon monoxide (CO) is odorless and colorless. Running a generator in a garage, even with the door open, can let it build up and enter the home. Place the generator outdoors, far from the house, with the exhaust pointed away. Federal safety agencies, including the U.S. Consumer Product Safety Commission, publish detailed placement guidance — follow it and your manual.
  • Install battery-powered or battery-backup CO alarms on every level and near sleeping areas before the storm, and test them.
  • If an alarm sounds or anyone feels dizzy, nauseated or has a headache while a generator runs, get to fresh air and call emergency services.
  • A generator's built-in CO shutoff is a backup, not permission to run it near the house.

Placement and weather

  • Keep the generator on a flat, dry surface outdoors and clear of anything flammable.
  • Do not run it in the rain without a canopy or enclosure designed for generators; water and electricity do not mix.
  • Leave room around it for cooling and so exhaust is not drawn toward windows or air intakes.
  • Secure it against theft and flooding; storm surge and flood water can reach outdoor equipment.

Fuel handling

  • Turn the generator off and let it cool before refuelling.
  • Store gasoline in approved containers, outdoors or in a detached space, away from living areas and ignition sources, within local limits.
  • Gasoline degrades with time; fuel stabilizer and rotating stock help. Propane does not age the way gasoline does.
  • Do not store fuel near a water heater, furnace or other flame.

Backfeeding and home connections

SafetyNever connect a generator to a house by plugging it into a wall outlet with a male-to-male cord. This "backfeeding" can energize utility lines and kill line workers, and can start fires. A transfer switch or interlock, with an inlet box, installed by a licensed electrician, is the proper way; Wattstanding gives no wiring instructions.

See transfer switch vs. interlock kit and the compatibility matrix.

Battery power stations are different, not risk-free

A battery power station has no exhaust, so it avoids carbon monoxide, and makers specify indoor use within temperature and ventilation limits. Large lithium batteries still have fire and shock risks: use the maker's cables, keep ventilation clear, avoid heat and damaged units, and follow the manual.

Questions readers ask

Can I run a generator in my garage with the door open?
No. Carbon monoxide can still build up and enter the home. Place it outdoors, away from the house.
How far from the house should a generator be?
Safety agencies recommend placing it well away from the house with the exhaust pointed away from doors, windows and vents; follow your manual and current agency guidance for the distance.

Figures marked as Wattstanding calculations show their working; product figures come from the sources on each product page. How we work