Is it safe to run a generator in the garage?
Short answer
No. Never run a portable generator in a garage, even with the garage door fully open. Generators produce large amounts of carbon monoxide, an odorless gas that builds up quickly in enclosed and partly enclosed spaces and seeps into the house. The U.S. Consumer Product Safety Commission advises running generators outdoors only, at least 20 feet from the home, with the exhaust pointed away from doors, windows and vents.
Why an open door is not enough
A gasoline generator's exhaust contains carbon monoxide (CO). In open air it disperses. In a garage, a carport against the house, a shed, a basement or under a porch, it collects faster than an open door or a fan can clear it. The CPSC has repeatedly found that opening doors or windows does not provide enough ventilation to prevent dangerous CO buildup.
Attached garages share walls, doors and often air pathways with the house. CO can move from the garage into living spaces, including bedrooms above or next to it, while people are asleep.
Carbon monoxide is fast and silent
CO has no color, smell or taste. Early symptoms such as headache, dizziness, nausea and weakness are easy to mistake for tiredness or the flu, and high levels can cause unconsciousness before people realize what is happening. The CPSC estimates that dozens of people in the US die every year from CO poisoning linked to portable generators, many of them during storm-related outages.
If a CO alarm sounds, or anyone feels dizzy, sick or confused while a generator is running, get everyone outside to fresh air immediately and call 911. Do not go back inside until emergency responders say it is safe.
Where to put a generator instead
- Outdoors, at least 20 feet from the house, on a dry, level surface.
- Exhaust pointed away from your home and your neighbors' homes, and away from doors, windows, vents and air intakes.
- Not under a carport, porch roof or awning attached to the house, and not in a shed or crawl space.
- Protected from rain with a generator tent or cover designed for running use, never by moving it indoors. Water and electricity are a shock hazard.
Twenty feet means you need heavy-duty outdoor extension cords long enough to reach. For larger loads, an electrician-installed inlet box and transfer switch or interlock lets the generator stay outside while feeding your panel safely.
Protect yourself inside
- Install battery-powered or battery-backup CO alarms on every level of the home and outside sleeping areas.
- Test them before storm season and replace batteries.
- When buying a generator, look for models with an automatic CO shut-off, which stops the engine if carbon monoxide builds up around it.
Storing a generator in the garage
Storing a generator in a garage is common, but storing is not running. Let it cool completely before moving it inside, and store fuel in approved containers away from heat sources and appliances with pilot lights.
A battery alternative
Portable power stations produce no exhaust, so they can be used indoors. They cannot replace a large generator for whole-home loads, but they handle a fridge, CPAP, lights and electronics well. See power station vs. generator.
Frequently asked questions
Can I run a generator in my garage with the door open?
No. An open garage door does not provide enough ventilation, and carbon monoxide can still build up and enter the house. Run generators outdoors only, at least 20 feet from the home.
How far should a generator be from the house?
The U.S. Consumer Product Safety Commission advises at least 20 feet, with the exhaust pointed away from doors, windows and vents.
Can I run a generator on my porch or under a carport?
No. Porches, carports and covered areas next to the house can trap exhaust that then drifts indoors. Place the generator in the open, away from the home.
Is it safe to use a power station indoors?
Yes. Battery power stations produce no exhaust or carbon monoxide, so they are safe to use indoors, away from water and heat sources.
Sources and method
Runtime figures assume 85% of battery capacity reaches AC appliances and typical US appliance ratings. See exactly how we calculate. Found a mistake? Tell us and we will fix it.