Carbon Monoxide Safety and the 20-Foot Rule
Last verified: September 2026
Where you set the generator down is the most important safety decision of the whole install. Here's the rule that can save a life — and exactly how to follow it at your home. Rather talk it through? My number is (330) 200-8042.
Generator CO Safety and the 20-Foot Rule, at a Glance
Carbon monoxide from a running generator is invisible, odorless, and can kill in minutes — and it's also completely preventable. The single rule that matters most is where the generator runs: outdoors only, at least 20 feet from the house, exhaust pointed away from every window, door, and vent, with battery-backup CO alarms inside. There's a printable page-by-page version up top.
Common Questions
1 Why is carbon monoxide from a generator so dangerous?
It's invisible and odorless, so there's no natural warning, and it can build to dangerous levels within minutes in an enclosed or partly enclosed space. It crowds oxygen out of your blood, and early symptoms — headache, drowsiness — are easy to mistake for being tired.
2 How far from the house does the generator need to be?
The safety agencies advise at least 20 feet, measured to the nearest wall, with the exhaust pointed away from every window, door, and vent — yours and the neighbor's. When in doubt, more distance is always better.
3 Is it safe to run a generator in the garage with the door open?
No. An open garage door does not clear carbon monoxide fast enough, and it drifts into the attached house. The same is true of a shed, carport, or covered porch — run it fully outdoors only.
4 What are the symptoms of carbon monoxide poisoning?
Headache, dizziness, weakness, nausea, confusion, and sleepiness. If you suspect it, get everyone into fresh air immediately, call 911, and don't go back inside until responders say it's safe.
5 What does the automatic CO shutoff feature do?
It's a sensor, found on newer models and meeting the standard known as PGMA G300 or UL 2201, that shuts the engine off if carbon monoxide nearby climbs to a dangerous level. It's a valuable backstop — not a reason to run the generator any closer to the house.
6 Does the 20-foot rule change for a propane generator?
No. Propane makes less carbon monoxide than gasoline, but still makes real CO. The same outdoor placement and the same 20 feet apply no matter which fuel the generator burns.
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No shame in it — plenty of folks would rather hand it off, and that's what I'm here for. I'll come to your home, set it up right, and make sure it's working before I leave. Flat $99 per visit — no jargon, no upsell, and every visit is 30-day come-back-free.
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