At least 20 feet from the house, outdoors, with the exhaust directed away from windows, doors, and vents. That distance is U.S. Consumer Product Safety Commission guidance, the same figure used on this site’s carbon-monoxide placement page, and it applies to windows as much as to doors. Carbon monoxide can enter through a window that is only slightly open, through a dryer vent, or through a garage that “doesn’t count” because the door is up. Indoor, basement, crawl-space, and enclosed-porch use is unsafe even with a window open.
CPSC has repeated this guidance in its portable-generator safety materials and in 2026 winter-weather safety tips. If the current CPSC page or the label on the machine differs from memory, follow the current text. A 20-foot cord or inlet run is an electrical and a safety decision together: put the inlet where the generator can sit in that open area, not where the shortest cord lands the muffler under a bedroom window.
Install CO alarms as CPSC also advises, and never backfeed the house through a window well or a dryer outlet. The electrical hookup should be a listed inlet and an interlock or transfer switch.
This is not a permit calculation, a utility approval, or a substitute for a licensed electrician, HVAC contractor, or the authority having jurisdiction. Panel Headroom is an independent educational site. It is not a utility, a certification body, or a contractor. Electrical and generator work that is done incorrectly can cause fire, shock, or carbon monoxide poisoning. Use the adopted electrical code and manufacturer instructions; pull permits where required.