How far should a generator be from the house?

The rule: 20 feet, exhaust pointed away

• At least 20 feet from your home and any building. CPSC's 2026 hurricane-season warning says to run generators "outdoors only, at least 20 feet from homes and buildings, with exhaust directed away from windows, doors and vents."
• Measure from the generator to the building. NFPA says to measure the 20-foot distance "from the generator to the building," and to keep it 20 feet from all doors, windows and vent openings.
• That includes an attached garage. Ready.gov says generators and fuel should be at least 20 feet "from windows, doors and attached garages."
• Exhaust away from the house. NFPA says the exhaust "must be directed away from the building."

Twenty feet is a minimum, not a target. If you have the room, farther is better, as long as the generator stays dry and on level ground.

Why "3 feet" and "5 feet" in your manual don't mean you're safe

Owner's manuals give much shorter distances. They're answering a different question.

Distance	Who says it	What it's for
3 ft (1 m)	Honda	Keeping the generator from overheating, and the exhaust from igniting nearby materials
3–4 ft	OSHA	Clear space on all sides and above, for ventilation
5 ft (1.5 m)	Champion	Clearance from anything that can burn
20 ft	CPSC, NFPA, Ready.gov	Keeping carbon monoxide out of your home

Honda's manual, for example, says to keep the generator "at least 3 feet (1 meter) away from buildings" to prevent a fire. But on carbon monoxide, the same manual says to run it "OUTSIDE, far away from windows, doors, and vents," and "never operate a generator near open doors or windows."

So use both rules. Leave 3–5 feet of open space right around the generator, and keep the whole thing 20+ feet from the house.

What the CPSC death data shows

People die with the generator outside, not just inside. CPSC staff studied every generator CO death they found from 2011 through 2021.

• 22 deaths in 14 incidents happened in homes where the generator was outside, but near a window, door, AC unit or other opening. CO got in anyway.
• A three-person death involved a generator with a CO shut-off. It was outside, with the exhaust pointed toward an exterior door. CPSC says there probably wasn't enough CO near the generator to trigger the shut-off. It ran until the tank was empty.

That second case matters. A CO shut-off reacts to the air around the generator, not inside your house. Distance and exhaust direction are what keep CO out.

How to pick the spot

1. Walk 20 feet out from the nearest wall, door or window, including your neighbor's.
2. Check the wind. Champion's manual says to "carefully consider wind and air currents" when you position a generator. Don't put it upwind of an open window or a bedroom.
3. Point the exhaust away from the house and from any opening.
4. Keep 3–5 feet of clear space around it. No fences, bushes, woodpiles or fuel cans pressed up against it.
5. Use flat, dry, level ground. Not a slope, not a puddle.
6. Not under anything. No porch, deck, carport, awning or overhang.
7. Mind the vents. Keep it away from AC units, dryer vents, crawlspace vents and soffit vents, which can draw air inside.

Worked example: how long a cord do you need?

Say your generator sits 20 feet from the back wall. Your cord has to go from there, along the ground and around obstacles, to where you plug in.

• Straight-line distance: 20 ft
• Around a deck corner and along the wall: about 10 ft more
• Slack, so it isn't stretched tight: about 5 ft

Total: about 35 ft, so a 50-foot cord. Then check the cord's gauge is heavy enough for that length and your load. Our 30 amp vs 50 amp generator cord guide covers wire gauge.

Never shorten the distance to fit the cord you happen to own. Buy a longer one.

"How far can a generator be from the house?"

There's no CO limit on farther. The limits are practical:

• Cord length and voltage drop. WEN's manual warns that "long or thin cords" can drain the power reaching your device. Use a heavier gauge for a long run.
• Fuel and theft. You'll want to reach it to refuel, and you may want to lock it down.
• Neighbors. Their windows and doors need the same 20 feet.

What about a standby generator?

Permanent standby generators are a different product. They're installed to the maker's instructions and local codes by a dealer or electrician, and the clearances come from those documents. Don't apply the portable 20-foot rule to them, and don't copy a standby unit's spacing for a portable.

The rest of the safety basics

• Never run it in a garage, basement, shed or porch, even with doors open. See can you run a generator in a garage.
• Put CO alarms on every level of your home, Ready.gov says. Use battery or battery-backup alarms.
• In rain, keep it dry outdoors. Don't pull it closer to the house to shelter it. See running a generator in the rain.
• To power house circuits, use a transfer switch or interlock installed by a licensed electrician. See how to connect a generator to your house.

Run it outdoors only, 20+ feet from the house, away from windows and doors: generator carbon monoxide safety.