How far should a generator be from the house?

How far should a generator be from the house?

A portable generator should sit outdoors at least 20 feet (6 m) from the house, with the exhaust pointing away from it. Both the U.S. Consumer Product Safety Commission (CPSC) and the CDC give this figure. It protects against carbon monoxide (CO), a gas you cannot see or smell. If you have the room, NIST goes further and says 25 feet (7.6 m).

CPSC measures the 20 feet from the house. The CDC says at least 20 feet from doors, windows and vents. Use the longer of the two: 20 feet from every door, window and vent, including your neighbour’s.

Point the exhaust away from your home and from any other building people could enter. CPSC also says to keep windows and other openings closed in the exhaust path.

Can you run a generator in a garage?

No. CPSC says never to run a portable generator in a home, garage, basement, crawlspace, shed or on a porch, and never to leave a car running in an attached garage. The CDC adds carports to the list.

Opening the door does not change that rule. The next section covers why. Wondering about rain? The generator in rain guide covers covers and canopies that keep the exhaust clear.

Is a generator in a garage with the door open safe?

An open garage door does not make a generator safe to run in the garage. The CPSC danger label reads: “NEVER use inside a home or garage, EVEN IF doors and windows are open.”

Manufacturers say the same. Honda’s EU2200i manual says not to operate the generator in an enclosed or partly enclosed area “such as a garage (even if the door is open)”. A garage with one open door is a partly enclosed space. Honda’s manual says the exhaust gas can collect rapidly in such areas.

Most generator CO deaths (81%) occurred in residential locations, according to CPSC’s 2022 report.

What does each source say? Distance rules compared

CPSC and the CDC give 20 feet for carbon monoxide. NIST asks for 25 feet. Honda’s 3 feet is a fire clearance, not a CO distance. The table lists each rule and what it protects against. Checked on 2026-10-26.

Source	Rule	What it addresses
CPSC (2022 leaflet, 2024 releases)	Outdoors only, at least 20 ft (6 m) from the house; exhaust pointed away; never in a garage, even with doors open	Carbon monoxide
CDC PSA toolkit	At least 20 ft from doors, windows and vents; never in a garage or carport	Carbon monoxide
NIST generator safety	At least 25 ft (7.6 m) from your home	Carbon monoxide
Honda EU2200i manual (2020)	Run outside, away from windows, doors and vents; not in a garage even with the door open; 3 ft (1 m) from walls and vehicles	CO and fire/overheating clearance
UL 2201	Generator has a lower CO emission rate and shuts off when CO builds up around it	Built-in protection, no distance
PGMA G300	Generator shuts off when CO builds up around it	Built-in protection, no distance

The 3 ft (1 m) in the Honda manual is a clearance to prevent fire and overheating. It is not a CO distance. Honda’s manual also says to keep the generator outside and away from doors, windows and vents.

Treat 20 feet as the minimum and 25 feet as the better spot when your yard allows it. Where a local fire code or utility gives a longer distance, follow the longer one.

Does a CO shut-off mean I can run it closer?

No. A CO shut-off is a backup and does not replace distance. Honda’s manual says its CO-MINDER system “cannot prevent all danger” from carbon monoxide.

CPSC ran more than 140,000 simulations based on 511 portable generator deaths. It found that a generator meeting UL 2201 would avert nearly 100% of those deaths and one meeting PGMA G300 nearly 87%. CPSC also found UL 2201 conformance “appears to be minimal” and G300 conformance lacking on most models (February 23, 2022).

CPSC advises asking retailers for a generator with CO shut-off. A mandatory federal CO rule is still in the works: CPSC published a supplemental proposal on April 20, 2023, and the August 14, 2026 regulatory agenda lists the portable generator standard at the Final Rule Stage. Until it takes effect, a generator on a shelf may have no shut-off, so check the box and manual. Our generator size guide helps you pick a model.

How many people die from generator carbon monoxide?

CPSC estimates about 85 people a year die from CO poisoning from gasoline-powered portable generators. That is the 2017 to 2019 average in a report covering 2011 to 2021 (CPSC, August 4, 2022). A January 2024 CPSC release cites its latest report as nearly 100 deaths a year.

The two numbers come from different report years, so they are not a trend. CPSC counts non-fire CO deaths only.

Where do CO alarms go when you use a generator?

Put battery-operated CO alarms, or plug-in alarms with battery backup, on every level of the home and outside each separate sleeping area. CPSC gives this advice, and says to test them monthly and replace batteries as needed. It adds that interconnected alarms are best.

The battery matters during an outage. A plug-in alarm with no backup goes quiet when the power does. Check the label on each alarm to see whether it has a battery.

If an alarm sounds, get outside immediately and call emergency services (911 in the US and Canada, 999 in the UK, 000 in Australia). CPSC lists the symptoms as headache, dizziness, weakness, nausea, vomiting, sleepiness and confusion. Anyone with those symptoms near a running generator needs fresh air and a medical check.

Worked example: finding a 20 foot spot

A yard layout shows how the rule works in practice. Say your back door is on the rear wall and your generator cord is 25 feet (7.6 m).

1. Measure 20 feet (6.1 m) out from the nearest door, window or vent.
2. Measure the full cord route to the appliance or inlet, including bends and slack. A 25 foot cord gives only 5 feet (1.5 m) beyond a 20 foot direct distance, and the run from the door to the appliance uses that up fast.
3. If the cord is too short, buy a longer rated cord. Do not move the generator closer.
4. Face the exhaust away from the house and your neighbour’s windows.

The conversion is 20 ft × 0.3048 = 6.1 m. For the cord, 25 ft − 20 ft = 5 ft of slack.

Checklist before you start the generator

• Is the generator outside, at least 20 feet (6 m) from the house, with the exhaust pointing away?
• Is it clear of garages, carports, porches, sheds and crawlspaces?
• Are doors, windows and vents near it closed?
• Do you have working CO alarms with battery power on every level and outside sleeping areas?
• Did you read the generator’s label and manual, which may add rules of its own?

Planning to power the house through a panel? Read interlock kit vs transfer switch. For runtime, see how long a generator can run. For the rest of an outage plan, see the power outage emergency kit guide. More topics are under all guides.