Here’s the thing about carbon monoxide — you can’t see it, smell it, or taste it. And according to the CDC, you should never run your car or truck inside a garage that’s attached to your house, even with the garage door wide open. That open door is not enough to protect you.
The EPA puts it plainly: fumes can build up very quickly in both the garage and the living areas of your home. That means the bedroom, the kitchen, the couch where you’re watching TV — all of it. The gas doesn’t stay in the garage just because there’s a wall between them.
Generators are just as dangerous. The EPA warns that deadly levels of carbon monoxide can quickly build up inside garages, homes, crawlspaces, and sheds — and that those levels can linger for hours even after the generator has been turned off. That last part matters: even after you shut it off, the air can still be dangerous. Stay out and let it clear before going back in.
The same goes for charcoal grills and portable camping stoves — the Texas Department of Insurance specifically says never to use those inside, and never to run any gas-powered engine in your home or garage, even with doors and windows open.
One more thing: if your garage is detached (not connected to your house), the CDC says you can run a car inside with the garage door open to bring in fresh air — but that exception only applies to a fully detached garage. When in doubt, just take it outside.
The bottom line: if it has an engine or burns fuel, keep it outside and well away from any doors or windows. And if your home doesn’t already have a carbon monoxide detector, that’s worth bringing up with the adults in your household — it’s one of the simplest ways to catch a problem before it becomes a tragedy.